Switching Power Supply for Building Automation \u2014 The Practical Selection Guide<\/title>\n<\/head>\n<body>\n\n<div class=\"bd-post\">\n <style>\n @import url('https:\/\/fonts.googleapis.com\/css2?family=Manrope:wght@400;600;700&family=Roboto:wght@600;700&display=swap');\n\n .bd-post {\n --body-bg: #FFFFFF;\n --heading-ink: #000000;\n --text-primary: #333333;\n --text-secondary: #6E6E6E;\n --accent-text: #1A5F8A;\n --accent: #2C72B5;\n --accent-hot: #FD9649;\n --brand-blue: #479DE2;\n --card-fill: #F4F8FC;\n --card-border: #E0E0E0;\n --card-text: #333333;\n --card-text-secondary: #6E6E6E;\n --card-accent: #1A5F8A;\n --inverse-bg: #1E1E1E;\n --inverse-bg-2: #2C2C2C;\n --inverse-text: #FFFFFF;\n --inverse-text-secondary: #B0B0B0;\n --inverse-accent: #479DE2;\n --panel-fill: #FAFAFA;\n --btn-white: #FFFFFF;\n --btn-ink: #0D3972;\n --prose-width: 720px;\n --gap-attach: 16px;\n --gap-normal: 32px;\n --gap-section: 48px;\n --pad-compact: 16px;\n --pad-standard: 24px;\n font-family: \"Manrope\", sans-serif;\n font-size: 16px;\n font-weight: 400;\n line-height: 1.6;\n color: var(--text-primary);\n background: var(--body-bg);\n padding: 40px;\n max-width: 100%;\n box-sizing: border-box;\n }\n .bd-post a { overflow-wrap: anywhere; 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}\n }\n <\/style>\n <article class=\"bd-post-article\">\n <h1><\/h1>\n\n <h2>Why Switching Power Supplies Are the Backbone of Building Automation<\/h2>\n\n <p>Every DDC controller, every access control panel, every bank of sensors scattered across a commercial building \u2014 they all run on low-voltage DC power. The device that converts incoming AC mains into that clean, regulated DC is the switching power supply. It is easy to treat it as an afterthought. A metal box in the corner of the control cabinet. Something you spec at the last minute.<\/p>\n\n <p>That would be a mistake. The power supply is the single point of failure for every subsystem it feeds. Pick the wrong one, and you are not dealing with a power problem. You are dealing with controllers that reboot at random, sensors that report ghost readings, and a client who has lost confidence in the whole installation. This article covers every dimension of selecting a switching power supply for building automation, from voltage to certifications, so you make the right call the first time.<\/p>\n\n <h2>Voltage Selection \u2014 12V, 24V, or 48V for Your BAS?<\/h2>\n\n <p>Voltage is where every PSU selection starts. It is also where the least thought often goes. The rule is simple: match the voltage to your devices, not the other way around. But “my devices” is rarely a single type of equipment. A typical BAS control cabinet powers controllers, sensors, actuators, communication gateways, and security peripherals simultaneously \u2014 and they do not all speak the same voltage. Here is how to sort through each option.<\/p>\n\n <h3>12V DC \u2014 When to Use It for Access Control and Security Devices<\/h3>\n\n <p>Twelve volts is the legacy workhorse of security and low-power electronics. Door access readers, electric strikes, CCTV cameras, PIR occupancy sensors \u2014 these devices built their ecosystems around 12V decades ago, and the supply chain still defaults to it. If your project is access-control-heavy, 12V will feel natural.<\/p>\n\n <p>The trade-off is distance. At 12V, a 10-amp load running through 1.5 mm\u00b2 copper wire drops roughly 0.7 volts over a 15-meter round-trip. By 20 meters, the voltage at the far end has sagged enough that a door lock may chatter or a camera may brown out during IR night-mode switching. If your cable runs are short and your loads predictable, 12V works fine. If not, keep reading.<\/p>\n\n <h3>24V DC \u2014 The Industry Standard for Building Controllers and Sensors<\/h3>\n\n <p>Twenty-four volts is where building automation lives. DDC controllers from every major manufacturer \u2014 Johnson Controls, Honeywell, Siemens \u2014 run on 24V DC. So do field sensors (temperature, humidity, CO\u2082, pressure), damper and valve actuators, relay modules, and BACnet\/IP gateways. A single medium-sized commercial floor might have two to four 24V DIN-rail power supplies in its control cabinet, each feeding a different zone or subsystem.<\/p>\n\n <p>Why 24V won is straightforward. It stays within SELV (Safety Extra-Low Voltage) limits defined by IEC 60364-4-41, which means no shock hazard during maintenance. It also pushes roughly twice the power over the same copper as 12V for the same percentage voltage drop. At 10 amps on 1.5 mm\u00b2 wire, a 24V circuit reaches a 5% drop at roughly 40 to 50 meters \u2014 double the reach of 12V. For a floor-level control cabinet feeding devices across a 30-meter wing, 24V gets the job done without intermediate boosters.<\/p>\n\n <p>If you have to pick one voltage without knowing the full device list yet, pick 24V. The ecosystem is broad enough that you will almost certainly find compatible equipment.<\/p>\n\n <h3>48V DC \u2014 Long-Distance Runs and PoE Infrastructure<\/h3>\n\n <p>Forty-eight volts is less common in traditional BAS but growing fast, driven by Power over Ethernet. Under the 802.3bt (PoE Type 4) standard, a single Cat6A cable can deliver up to 100 watts at 48V. That is enough to power a small controller, a touch panel, and a handful of sensors through one RJ45 jack. For new construction where the ICT contractor is already pulling structured cable, PoE-based BAS can eliminate separate power wiring entirely.<\/p>\n\n <p>Outside PoE, 48V also makes sense for very long DC distribution runs. Think of a central equipment room feeding devices across a 200-meter warehouse or a high-rise riser where voltage drop would cripple a 24V system. The trade-off is device compatibility. The 48V BAS ecosystem is still thin compared to 24V, and the equipment that does exist carries a price premium. Unless PoE or long-haul distribution is a hard requirement, 24V remains the safer default.<\/p>\n<img decoding=\"async\" src=\"https:\/\/www.omch.com\/wp-content\/uploads\/2026\/07\/Gemini_Generated_Image_a6vl4ia6vl4ia6vl.webp\" alt=\"Switching Power Supply for Building Automation\" class=\"bd-post-image\" loading=\"lazy\">\n \n <div class=\"bp-3-quickref bd-reveal\">\n <div class=\"bp-3-volt\">\n <div class=\"bp-3-volt-icon\"><svg width=\"20\" height=\"20\" viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><polygon points=\"13 2 3 14 12 14 11 22 21 10 12 10 13 2\"\/><\/svg><\/div>\n <div class=\"bp-3-volt-label\">12V DC<\/div>\n <div class=\"bp-3-volt-desc\">Access control, security cameras, short cable runs<\/div>\n <\/div>\n <div class=\"bp-3-volt\">\n <div class=\"bp-3-volt-icon\"><svg width=\"20\" height=\"20\" viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><polygon points=\"13 2 3 14 12 14 11 22 21 10 12 10 13 2\"\/><\/svg><\/div>\n <div class=\"bp-3-volt-label\">24 V CC<\/div>\n <div class=\"bp-3-volt-desc\">DDC controllers, sensors, actuators \u2014 the BAS standard<\/div>\n <div class=\"bp-3-volt-badge\">RECOMMENDED<\/div>\n <\/div>\n <div class=\"bp-3-volt\">\n <div class=\"bp-3-volt-icon\"><svg width=\"20\" height=\"20\" viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><polygon points=\"13 2 3 14 12 14 11 22 21 10 12 10 13 2\"\/><\/svg><\/div>\n <div class=\"bp-3-volt-label\">48V DC<\/div>\n <div class=\"bp-3-volt-desc\">PoE infrastructure, long-distance distribution<\/div>\n <\/div>\n <\/div>\n\n <h2>Power Sizing \u2014 How to Calculate Load and Avoid the “Undersized PSU” Trap<\/h2>\n\n <p>Power sizing seems like arithmetic: add up all the device wattages, pick the next PSU up, done. In practice, three factors regularly trip up even experienced engineers. Accounting for them upfront is the difference between a control cabinet that runs for a decade and one that generates monthly service calls.<\/p>\n\n <h3>Step 1 \u2014 Add Up Your Real Load, Device by Device<\/h3>\n\n <p>Start with a load schedule. For each device on the PSU, write down its nominal power draw, then tally the total. Here are realistic ranges for common BAS equipment based on currently available mid-range product lines:<\/p>\n\n <div class=\"table-wrapper\">\n <table>\n <thead><tr><th>Tipo de dispositivo<\/th><th>Typical Power Draw (24V DC)<\/th><\/tr><\/thead>\n <tbody>\n <tr><td>DDC controller (mid-size, ~32 I\/O points)<\/td><td>8\u201315 W<\/td><\/tr>\n <tr><td>Touch panel \/ operator display (7\u201310 inch)<\/td><td>10\u201325 W<\/td><\/tr>\n <tr><td>Field sensor (temperature, humidity, CO\u2082)<\/td><td>1\u20133 W each<\/td><\/tr>\n <tr><td>Damper\/valve actuator (spring-return, 10 Nm)<\/td><td>5\u201315 W (running), 0 W (holding, if mechanical)<\/td><\/tr>\n <tr><td>Door electric strike<\/td><td>10\u201330 W (pulse)<\/td><\/tr>\n <tr><td>IP surveillance camera (PoE or 24V)<\/td><td>5\u201315 W<\/td><\/tr>\n <tr><td>BACnet router \/ protocol gateway<\/td><td>3\u20138 W<\/td><\/tr>\n <\/tbody>\n <\/table>\n <\/div>\n\n <p>The trap is sensor count. Five sensors at 2 W each is 10 W \u2014 trivial. Two hundred sensors across a campus is 400 W, and that number often only surfaces after the PSU is already installed. Build your load schedule early, and keep it updated as the device list evolves.<\/p>\n\n <h3>Step 2 \u2014 Add 20\u201330% Headroom (and Know When to Add More)<\/h3>\n\n <p>The standard rule is to multiply total load by 1.2 to 1.3 and select a PSU at or above that number. A 168 W total (7 A at 24V) points to a 240 W (10 A) unit, not a 200 W (8.3 A) one.<\/p>\n\n <p>Three scenarios push that multiplier higher:<\/p>\n\n <p><strong>Motor and solenoid inrush.<\/strong> An electric strike or spring-return actuator can draw two to three times its running current for the first 100 to 200 milliseconds. If multiple actuators fire simultaneously during a fire-alarm sequence, the instantaneous load spike can trip the PSU’s over-current protection \u2014 and every controller on that rail reboots mid-event.<\/p>\n\n <p><strong>High-temperature cabinets.<\/strong> Most DIN-rail PSUs publish a derating curve. A typical unit, such as the Mean Well NDR-240 series, delivers 100% of rated power at 40\u00b0C ambient, derates to roughly 80% at 50\u00b0C, and falls to about 60% at 60\u00b0C. A sealed NEMA enclosure on a sun-exposed rooftop in summer can easily reach 50\u00b0C inside. If your load is 180 W and the PSU is rated 240 W at 25\u00b0C, you might think you have 25% headroom. At 50\u00b0C inside the cabinet, the real headroom is closer to zero.<\/p>\n\n <p><strong>Future expansion.<\/strong> Building automation systems grow over time. A floor renovation adds 30 more VAV controllers. A security upgrade adds more cameras. If you size to the exact load today, you will be replacing PSUs within three to five years. The labor to swap a DIN-rail unit in a live cabinet costs far more than the extra 30% capacity you could have bought upfront.<\/p>\n\n <h3>Step 3 \u2014 Separate Critical Loads from Noisy Loads<\/h3>\n\n <p>Here is a failure pattern that generates more service calls than any undersized PSU: a door controller reboots every time the electric strike fires. The cause is not a software bug or a faulty strike. It is a voltage sag caused by putting a high-inrush inductive load on the same PSU rail as sensitive electronics.<\/p>\n\n <p>When a relay coil or solenoid de-energizes, the collapsing magnetic field generates a reverse voltage spike that can reach 10 to 20 times the nominal coil voltage. Without a flyback diode, that spike dumps straight onto the DC rail as conducted EMI \u2014 enough to brown out or reset a microcontroller-based DDC.<\/p>\n\n <p>The fix is simple and costs almost nothing at design time. Dedicate one PSU to control and communication devices (DDC, sensors, gateways, displays). Put switching loads (locks, relays, solenoid valves) on a separate PSU. A third PSU for auxiliary loads like LED indicators, cabinet lighting, and convenience outlets is optional but keeps troubleshooting cleaner. Label each PSU’s output with its served function. The technician who opens this cabinet at 2 AM will thank you.<\/p>\n\n <h2>DIN Rail, Panel Mount, or Enclosed? Matching Form Factor to Your Installation<\/h2>\n\n <p>By this point, you have chosen a voltage and calculated your power budget. Now the question is physical: what does the PSU look like and where does it live?<\/p>\n\n <p>For building automation control cabinets, DIN-rail mounting \u2014 specifically TS35\/7.5 profile \u2014 is the default and the right answer in most cases. A DIN-rail PSU snaps onto the same rail as your circuit breakers, relays, and terminal blocks, making the cabinet layout clean and modular. When a unit fails \u2014 and eventually, every PSU fails \u2014 swapping it takes 30 seconds. Unscrew two terminals, release the DIN clip, snap in the replacement, re-terminate. No drilling, no brackets, no downtime beyond a power cycle.<\/p>\n\n <p>Panel-mount or chassis-mount PSUs are larger, typically 200 W and above, and bolt directly to the backplane of a cabinet. They make sense when you need high power density in a single unit \u2014 say, a 480 W supply feeding an entire floor’s worth of controllers \u2014 or when you are building a custom enclosure that does not have DIN rail at all. The trade-off is serviceability. Replacing a panel-mount unit means tools, time, and possibly shutting down adjacent equipment to access the mounting screws.<\/p>\n\n <p>Enclosed or IP-rated PSUs are for locations where the environment, not the load, drives the decision. A corridor ceiling junction box. A parking garage equipment closet. An outdoor air-handling unit. Look for IP65 or better with a sealed cable gland entry and conformally coated PCBs. Expect to pay two to three times the price of an equivalent DIN-rail unit. Budget for it early, because retrofitting enclosures after the fact is expensive.<\/p>\n\n <h2>Efficiency, Thermal Performance, and What “Industrial-Grade” Really Means<\/h2>\n\n <p>Efficiency ratings on a PSU datasheet \u2014 89%, 91%, 93% \u2014 look like small differences, and on a single unit, they are. The gap opens up at scale. A building with 50 DIN-rail PSUs running 24\/7, each dissipating an extra 10 W of heat because of a 3% efficiency gap, burns an additional 4,380 kWh per year. That is enough to matter on both the energy bill and the cooling load. Over a 10-year equipment lifecycle, that delta can pay for a significant fraction of the PSU budget itself.<\/p>\n\n <p>Thermal design matters more than the headline efficiency number. Fan-cooled PSUs achieve higher power density in a smaller chassis, but fans have bearings, and bearings wear out. In a sealed BAS control cabinet where nobody opens the door for five years, a failed fan means a PSU cooking itself to death with no audible warning. Convection-cooled, fanless designs cost slightly more per watt but eliminate the single most common mechanical failure point. For building automation, where reliability trumps density, fanless is the right default.<\/p>\n\n <p>Component quality is where the real difference hides \u2014 the gap between a PSU rated for commercial use and one built to an industrial standard. The clearest signal is the electrolytic capacitor temperature rating. Capacitors are the life-limiting component in any switching PSU. Their electrolyte dries out over time, and heat accelerates that process exponentially. A capacitor rated at 105\u00b0C, operated at a 40\u00b0C internal ambient, can outlast an 85\u00b0C-rated capacitor by a factor of three to four, following the Arrhenius rate law that governs electrolyte degradation. Manufacturers who specify Japanese-brand capacitors \u2014 Rubycon ZLH series, Chemi-Con KZE, Nichicon PW \u2014 are making a bill-of-materials choice that directly extends field life. Look for capacitor brand and temperature rating in the datasheet. If neither is published, ask.<\/p>\n\n \n <div class=\"bp-1-stat bd-reveal\">\n <div class=\"bp-1-stat-numeral\">3\u20134\u00d7<\/div>\n <div class=\"bp-1-stat-caption\">\n <div class=\"bp-1-stat-label\">Longer field life<\/div>\n <div class=\"bp-1-stat-desc\">105\u00b0C-rated capacitors outlast 85\u00b0C equivalents by a factor of three to four, following the Arrhenius rate law. This bill-of-materials choice directly extends PSU service life.<\/div>\n <\/div>\n <\/div>\n\n <h2>Protection Features and Certifications \u2014 What to Look for on the Spec Sheet<\/h2>\n\n <p>Protection features are the PSU’s first line of defense. Certifications are the third-party vote of confidence. Both need to be on your checklist. A PSU with great specs but no independent safety testing is a liability waiting for an inspector to find it.<\/p>\n\n <h3>The Five Essential Protection Features Every BAS PSU Should Have<\/h3>\n\n <p>Every DIN-rail PSU marketed for industrial use will claim to have protections. What matters is what happens when they activate \u2014 particularly whether the unit recovers automatically or latches off.<\/p>\n\n <div class=\"table-wrapper\">\n <table>\n <thead><tr><th>Protecci\u00f3n<\/th><th>What It Prevents<\/th><th>What to Check<\/th><\/tr><\/thead>\n <tbody>\n <tr><td>Over-Voltage Protection (OVP)<\/td><td>Output voltage runaway that fries downstream electronics<\/td><td>Trip threshold and response time<\/td><\/tr>\n <tr><td>Over-Current \/ Overload Protection (OCP)<\/td><td>Thermal damage from sustained overcurrent<\/td><td>Constant-current limiting vs. hiccup mode<\/td><\/tr>\n <tr><td>Short-Circuit Protection (SCP)<\/td><td>Catastrophic failure from wiring faults or load shorts<\/td><td><strong>Auto-recovery<\/strong> vs. latch-off (auto-recovery is mandatory for unattended cabinets)<\/td><\/tr>\n <tr><td>Over-Temperature Protection (OTP)<\/td><td>Thermal runaway in high-ambient or fan-failure scenarios<\/td><td>Auto-restart after cooling<\/td><\/tr>\n <tr><td>Surge Protection<\/td><td>Damage from lightning-induced or switching transients on the mains input<\/td><td>Compliance with IEC 61000-4-5; Class 3 (2 kV line-to-ground) is adequate for most indoor BAS; Class 4 (4 kV) for outdoor-fed panels<\/td><\/tr>\n <\/tbody>\n <\/table>\n <\/div>\n\n <p>SCP recovery behavior is the one to scrutinize. A latch-off PSU that trips on a momentary wiring short will sit dead until someone physically cycles power. In a locked BAS cabinet in a remote mechanical room, that could be days. Auto-recovery with hiccup-mode retry \u2014 where the PSU attempts to restart every few seconds until the short clears \u2014 is the only acceptable behavior for unattended building systems.<\/p>\n\n <h3>UL 508, UL 1310, EN 62368, CE \u2014 Making Sense of the Certification Alphabet<\/h3>\n\n <p>Certifications are a language, and most spec sheets assume you speak it. Here is a translation table for the marks that actually matter in building automation procurement:<\/p>\n\n <div class=\"table-wrapper\">\n <table>\n <thead><tr><th>Certification<\/th><th>Regi\u00f3n<\/th><th>What It Covers<\/th><th>Why It Matters for BAS<\/th><\/tr><\/thead>\n <tbody>\n <tr><td>CE<\/td><td>EU \/ EEA<\/td><td>Baseline safety + EMC compliance (self-declared by manufacturer)<\/td><td>Minimum barrier to entry for European projects; without it, customs clearance may be denied<\/td><\/tr>\n <tr><td>UL 508<\/td><td>North America<\/td><td>Industrial control equipment safety<\/td><td>Required by most US electrical inspectors for control panel acceptance; covers the PSU as a component within a larger industrial control panel<\/td><\/tr>\n <tr><td>UL 1310<\/td><td>North America<\/td><td>Class 2 power units \u2014 output limited to \u226460 V DC, \u22648 A, and \u2264100 VA per channel<\/td><td>Critical where fire safety codes require power-limited circuits (plenum spaces, historic buildings, healthcare); a Class 2 output means no conduit required for low-voltage wiring<\/td><\/tr>\n <tr><td>EN 62368-1<\/td><td>EU (IEC 62368 globally)<\/td><td>Safety for audio\/video, IT, and communication equipment \u2014 the modern successor to EN 60950<\/td><td>Increasingly adopted as the baseline safety standard for BAS equipment with communication interfaces; hazard-based rather than prescriptive<\/td><\/tr>\n <\/tbody>\n <\/table>\n <\/div>\n\n <p>For export projects, the safest combination is CE + UL. UL can be substituted with ETL or CSA \u2014 all three are OSHA-recognized NRTL marks in the US. If your project includes plenum-rated spaces or ungrounded historical buildings, UL 1310 Class 2 compliance is the specification that will keep the electrical inspector from flagging your installation.<\/p>\n\n <h3>How to Verify Certifications Are Real (Not Just Logos on a Webpage)<\/h3>\n\n <p>Certification fraud is common enough in the industrial power supply market that a five-minute verification step is worth the effort. UL certifications can be checked through the UL Product iQ database at productiq.ul.com. Enter the manufacturer’s name or UL file number and confirm the certificate is active and covers the specific model you are buying. For CE marking, request the EU Declaration of Conformity document. A legitimate DoC lists the specific harmonized standards the product was tested against \u2014 for example, EN 55032:2015 + A1:2020 for EMC emissions. A CE logo without an accompanying DoC is not a valid CE mark. Reputable suppliers provide these documents on request. Hesitation is a red flag.<\/p>\n\n \n <div class=\"bp-cta-mid bd-reveal\">\n <div class=\"bp-cta-mid-icon\"><svg width=\"24\" height=\"24\" viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"var(--accent)\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><circle cx=\"12\" cy=\"12\" r=\"10\"\/><path d=\"M9.09 9a3 3 0 015.83 1c0 2-3 3-3 3\"\/><line x1=\"12\" y1=\"17\" x2=\"12.01\" y2=\"17\"\/><\/svg><\/div>\n <div class=\"bp-cta-mid-text\">Matching PSU specs across an entire BAS project takes time. If you need a second pair of eyes on your device list, our selection engineers can help.<\/div>\n <a class=\"bp-cta-mid-btn\" href=\"https:\/\/www.omch.com\/es\/contact\/\" target=\"_self\">Request Selection Support<\/a>\n <\/div>\n\n <h2>Load Separation and Wiring \u2014 Simple Practices That Prevent Field Failures<\/h2>\n<img decoding=\"async\" src=\"https:\/\/www.omch.com\/wp-content\/uploads\/2026\/07\/Gemini_Generated_Image_kb1g7zkb1g7zkb1g.webp\" alt=\"Switching Power Supply for Building Automation\" class=\"bd-post-image\" loading=\"lazy\">\n\n <p>Most PSU selection guides end after the spec sheet. But a perfectly chosen power supply, installed poorly, will generate the same service calls as the wrong one. Two real-world patterns show why installation practice belongs in the selection conversation.<\/p>\n\n <p><strong>Pattern 1: the 2 PM controller reboot.<\/strong> A new access control system on a commercial office floor works flawlessly \u2014 except every weekday at roughly 2 PM, when all four door controllers on the east wing reboot simultaneously. After three site visits and two controller replacements, the root cause surfaces. All controllers share one PSU with the electric strikes. And 2 PM is when the afternoon cleaning crew badges in through the loading dock, triggering all four strikes in rapid succession. Each strike’s inductive kickback drags the DC rail low enough to brown out the controller MCUs.<\/p>\n\n <p><strong>Pattern 2: the ghost sensor.<\/strong> A bank of CO\u2082 sensors on a VAV system reports readings that drift 200 to 300 ppm every afternoon, then recover overnight. Sensors are replaced twice. The culprit is not the sensors. It is the PSU’s output ripple, which increases as the cabinet temperature rises through the afternoon. An oscilloscope on the 24V rail shows 300 mV of ripple at 4 PM versus 80 mV at 8 AM. The sensor’s analog front end cannot reject the noise.<\/p>\n\n \n <div class=\"bp-2-diagnosis bd-reveal\">\n <div class=\"bp-2-case\">\n <div class=\"bp-2-case-head\">\n <span class=\"bp-2-case-icon\"><svg width=\"20\" height=\"20\" viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M10.29 3.86 1.82 18a2 2 0 001.71 3h16.94a2 2 0 001.71-3L13.71 3.86a2 2 0 00-3.42 0z\"\/><line x1=\"12\" y1=\"9\" x2=\"12\" y2=\"13\"\/><line x1=\"12\" y1=\"17\" x2=\"12.01\" y2=\"17\"\/><\/svg><\/span>\n <span class=\"bp-2-case-title\">Pattern 1: The 2 PM Reboot<\/span>\n <\/div>\n <div class=\"bp-2-case-cause-label\">Root cause:<\/div>\n <div class=\"bp-2-case-cause-text\">Controllers sharing a PSU with electric strikes \u2014 inductive kickback from simultaneous strike activation browns out the MCUs.<\/div>\n <\/div>\n <div class=\"bp-2-case\">\n <div class=\"bp-2-case-head\">\n <span class=\"bp-2-case-icon\"><svg width=\"20\" height=\"20\" viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><polyline points=\"22 12 18 12 15 21 9 3 6 12 2 12\"\/><\/svg><\/span>\n <span class=\"bp-2-case-title\">Pattern 2: The Ghost Sensor<\/span>\n <\/div>\n <div class=\"bp-2-case-cause-label\">Root cause:<\/div>\n <div class=\"bp-2-case-cause-text\">PSU output ripple increasing with cabinet temperature \u2014 the sensor’s analog front end cannot reject the noise on the DC rail.<\/div>\n <\/div>\n <\/div>\n\n <p>Three rules prevent most of these failures at zero additional hardware cost:<\/p>\n\n <ul>\n <li>Separate control from switching loads. DDC controllers, sensors, gateways, and communication modules share one PSU. Electric strikes, solenoid valves, relay coils, and motorized actuators share a different PSU. The two rails are electrically independent. No single switching event can disturb the control electronics.<\/li>\n <li>Calculate voltage drop for every cable run over 30 meters. At 24V and 10A on 1.5 mm\u00b2 copper, a 60-meter round trip drops roughly 7V \u2014 nearly 30% of the nominal voltage, enough that end-of-line devices will malfunction. Either upsize the cable (2.5 mm\u00b2 halves the drop for the same length) or add a local PSU at the far end.<\/li>\n <li>Label every PSU output. A piece of heat-shrink or a clip-on cable marker with “DDC-Zone-3” or “Lock-PSU-East” saves the next technician 80% of their troubleshooting time. In a cabinet with four identical-looking DIN-rail PSUs, unlabeled outputs turn a 10-minute swap into a two-hour tracing exercise.<\/li>\n <\/ul>\n\n <h2>The Buyer’s Selection Checklist \u2014 A Framework for Comparing Switching PSUs Objectively<\/h2>\n\n <p>You have worked through voltage, power, form factor, efficiency, protections, certifications, and installation practice. The following table pulls every dimension into a single checklist. Print it, keep it with your project specs, and run every candidate PSU through it before ordering.<\/p>\n\n <div class=\"table-wrapper\">\n <table>\n <thead><tr><th>#<\/th><th>Selection Dimension<\/th><th>What to Check<\/th><th>Your Project<\/th><\/tr><\/thead>\n <tbody>\n <tr><td>1<\/td><td>Tensi\u00f3n de salida<\/td><td>12V \/ 24V \/ 48V \u2014 matches all connected devices<\/td><td><\/td><\/tr>\n <tr><td>2<\/td><td>Total Power<\/td><td>Sum of all device loads \u00d7 1.2\u20131.3 headroom<\/td><td><\/td><\/tr>\n <tr><td>3<\/td><td>Montaje<\/td><td>DIN rail (TS35\/7.5) \/ panel-mount \/ enclosed (IP-rated)<\/td><td><\/td><\/tr>\n <tr><td>4<\/td><td>Eficacia<\/td><td>\u226585% at 230V full load (\u226590% preferred for 24\/7 operation)<\/td><td><\/td><\/tr>\n <tr><td>5<\/td><td>Cooling<\/td><td>Convection (fanless) \u2014 strongly preferred for sealed cabinets<\/td><td><\/td><\/tr>\n <tr><td>6<\/td><td>Protections<\/td><td>OVP, OCP, SCP with auto-recovery, OTP, surge (IEC 61000-4-5 Class 3+)<\/td><td><\/td><\/tr>\n <tr><td>7<\/td><td>Certificaciones<\/td><td>CE + UL 508 or UL 1310 Class 2 (per target market and installation environment)<\/td><td><\/td><\/tr>\n <tr><td>8<\/td><td>Temperatura de funcionamiento<\/td><td>At least \u221210\u00b0C to +60\u00b0C; review derating curve at your cabinet’s expected ambient<\/td><td><\/td><\/tr>\n <tr><td>9<\/td><td>Load Separation<\/td><td>Control electronics on a dedicated PSU, switching loads on a separate PSU<\/td><td><\/td><\/tr>\n <tr><td>10<\/td><td>Supplier Verification<\/td><td>UL certificate verifiable at productiq.ul.com; EU DoC available; third-party test reports provided on request<\/td><td><\/td><\/tr>\n <\/tbody>\n <\/table>\n <\/div>\n\n <p>Selection is not a one-time decision. Device lists change during commissioning. A client adds a floor. A security consultant specifies more cameras. The PSU you sized at design development may be marginal by final acceptance. Build in enough headroom that a late addition does not force a re-order. When you do need to source PSUs that check every box on this list, look for suppliers who make their certifications and derating curves publicly available rather than buried behind a sales contact form. Transparency in the datasheet is a reasonable proxy for transparency in the product.<\/p>\n\n <p><em>For projects requiring DIN-rail switching power supplies across the 15 W to 480 W range \u2014 with CE, RoHS, and ISO 9001 certifications backed by 38 years of manufacturing experience \u2014 OMCH ‘s full switch-mode power supply catalog is available online, with product selection support for matching specifications to project requirements.<\/em><\/p>\n\n \n <div class=\"bp-cta-end bd-reveal\">\n <div class=\"bp-cta-end-icon\"><svg width=\"32\" height=\"32\" viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><rect x=\"2\" y=\"4\" width=\"20\" height=\"16\" rx=\"2\"\/><path d=\"M22 7-10 10L2 7\"\/><\/svg><\/div>\n <div class=\"bp-cta-end-title\">Match Your PSU Specs to Your Project<\/div>\n <div class=\"bp-cta-end-subtitle\">Send us your device list. Our application engineers review it against 15 W\u2013480 W DIN-rail options with CE, RoHS, and ISO 9001 certifications \u2014 and recommend the right fit.<\/div>\n <a class=\"bp-cta-end-btn\" href=\"https:\/\/www.omch.com\/es\/contact\/\" target=\"_self\">Get Specifications Matched<\/a>\n <\/div>\n\n <h2>References<\/h2>\n\n <ol>\n <li>UL Standards & Engagement. “UL 1310 \u2014 Standard for Class 2 Power Units.” <a href=\"https:\/\/standardscatalog.ul.com\/ProductDetail.aspx?productId=UL1310\">https:\/\/standardscatalog.ul.com\/ProductDetail.aspx?productId=UL1310<\/a><\/li>\n <li>IEC. “IEC 61000-4-5: Electromagnetic Compatibility (EMC) \u2014 Part 4-5: Testing and Measurement Techniques \u2014 Surge Immunity Test.” <a href=\"https:\/\/webstore.iec.ch\/publication\/4264\">https:\/\/webstore.iec.ch\/publication\/4264<\/a><\/li>\n <li>Mean Well. “NDR-240 Series \u2014 240W Industrial DIN Rail Power Supply Datasheet.” <a href=\"https:\/\/www.meanwell.com\/productPdf.aspx?i=28\">https:\/\/www.meanwell.com\/productPdf.aspx?i=28<\/a><\/li>\n <li>IEEE. “802.3bt-2018 \u2014 IEEE Standard for Ethernet Amendment 2: Power over Ethernet over 4 Pairs.” <a href=\"https:\/\/standards.ieee.org\/standard\/802_3bt-2018.html\">https:\/\/standards.ieee.org\/standard\/802_3bt-2018.html<\/a><\/li>\n <li>OMCH. “Switch Mode Power Supply \u2014 DIN-Rail and Enclosed Series.” <a href=\"https:\/\/www.omch.com\/es\/switch-mode-power-supply\/\">https:\/\/www.omch.com\/switch-mode-power-supply\/<\/a><\/li>\n <li>OMCH. “OMCH \u2014 Industrial Automation Components Manufacturer.” <a href=\"https:\/\/www.omch.com\/es\/\">https:\/\/www.omch.com\/<\/a><\/li>\n <\/ol>\n <\/article>\n<\/div>\n\n<\/body><\/html>\n\n\n\n\n<p><\/p>","protected":false},"excerpt":{"rendered":"<p>Switching Power Supply for Building Automation \u2014 The Practical Selection Guide Why Switching Power Supplies Are the Backbone of Building Automation Every DDC controller, every access control panel, every bank of sensors scattered across a commercial building \u2014 they all run on low-voltage DC power. The device that converts incoming AC mains into that clean, […]<\/p>","protected":false},"author":4,"featured_media":12038,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_seopress_robots_primary_cat":"none","_seopress_titles_title":"Switching Power Supply for Building Automation \u2014 The Practical Selection Guide","_seopress_titles_desc":"Practical selection guide for switching power supplies in building automation. Learn how to choose voltages, size power budgets, and prevent field failures.","_seopress_robots_index":"","footnotes":""},"categories":[79],"tags":[],"class_list":["post-12035","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-mmlblog"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.omch.com\/es\/wp-json\/wp\/v2\/posts\/12035","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.omch.com\/es\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.omch.com\/es\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.omch.com\/es\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.omch.com\/es\/wp-json\/wp\/v2\/comments?post=12035"}],"version-history":[{"count":1,"href":"https:\/\/www.omch.com\/es\/wp-json\/wp\/v2\/posts\/12035\/revisions"}],"predecessor-version":[{"id":12041,"href":"https:\/\/www.omch.com\/es\/wp-json\/wp\/v2\/posts\/12035\/revisions\/12041"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.omch.com\/es\/wp-json\/wp\/v2\/media\/12038"}],"wp:attachment":[{"href":"https:\/\/www.omch.com\/es\/wp-json\/wp\/v2\/media?parent=12035"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.omch.com\/es\/wp-json\/wp\/v2\/categories?post=12035"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.omch.com\/es\/wp-json\/wp\/v2\/tags?post=12035"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}

{"id":12035,"date":"2026-07-16T01:49:18","date_gmt":"2026-07-16T01:49:18","guid":{"rendered":"https:\/\/www.omch.com\/?p=12035"},"modified":"2026-07-16T01:49:20","modified_gmt":"2026-07-16T01:49:20","slug":"switching-power-supply-for-building-automation","status":"publish","type":"post","link":"https:\/\/www.omch.com\/es\/switching-power-supply-for-building-automation\/","title":{"rendered":"Switching Power Supply for Building Automation \u2014 The Practical Selection Guide"},"content":{"rendered":"\n\n \n \n Switching Power Supply for Building Automation \u2014 The Practical Selection Guide<\/title>\n<\/head>\n<body>\n\n<div class=\"bd-post\">\n <style>\n @import url('https:\/\/fonts.googleapis.com\/css2?family=Manrope:wght@400;600;700&family=Roboto:wght@600;700&display=swap');\n\n .bd-post {\n --body-bg: #FFFFFF;\n --heading-ink: #000000;\n --text-primary: #333333;\n --text-secondary: #6E6E6E;\n --accent-text: #1A5F8A;\n --accent: #2C72B5;\n --accent-hot: #FD9649;\n --brand-blue: #479DE2;\n --card-fill: #F4F8FC;\n --card-border: #E0E0E0;\n --card-text: #333333;\n --card-text-secondary: #6E6E6E;\n --card-accent: #1A5F8A;\n --inverse-bg: #1E1E1E;\n --inverse-bg-2: #2C2C2C;\n --inverse-text: #FFFFFF;\n --inverse-text-secondary: #B0B0B0;\n --inverse-accent: #479DE2;\n --panel-fill: #FAFAFA;\n --btn-white: #FFFFFF;\n --btn-ink: #0D3972;\n --prose-width: 720px;\n --gap-attach: 16px;\n --gap-normal: 32px;\n --gap-section: 48px;\n --pad-compact: 16px;\n --pad-standard: 24px;\n font-family: \"Manrope\", sans-serif;\n font-size: 16px;\n font-weight: 400;\n line-height: 1.6;\n color: var(--text-primary);\n background: var(--body-bg);\n padding: 40px;\n max-width: 100%;\n box-sizing: border-box;\n }\n .bd-post a { overflow-wrap: anywhere; 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}\n }\n <\/style>\n <article class=\"bd-post-article\">\n <h1><\/h1>\n\n <h2>Why Switching Power Supplies Are the Backbone of Building Automation<\/h2>\n\n <p>Every DDC controller, every access control panel, every bank of sensors scattered across a commercial building \u2014 they all run on low-voltage DC power. The device that converts incoming AC mains into that clean, regulated DC is the switching power supply. It is easy to treat it as an afterthought. A metal box in the corner of the control cabinet. Something you spec at the last minute.<\/p>\n\n <p>That would be a mistake. The power supply is the single point of failure for every subsystem it feeds. Pick the wrong one, and you are not dealing with a power problem. You are dealing with controllers that reboot at random, sensors that report ghost readings, and a client who has lost confidence in the whole installation. This article covers every dimension of selecting a switching power supply for building automation, from voltage to certifications, so you make the right call the first time.<\/p>\n\n <h2>Voltage Selection \u2014 12V, 24V, or 48V for Your BAS?<\/h2>\n\n <p>Voltage is where every PSU selection starts. It is also where the least thought often goes. The rule is simple: match the voltage to your devices, not the other way around. But “my devices” is rarely a single type of equipment. A typical BAS control cabinet powers controllers, sensors, actuators, communication gateways, and security peripherals simultaneously \u2014 and they do not all speak the same voltage. Here is how to sort through each option.<\/p>\n\n <h3>12V DC \u2014 When to Use It for Access Control and Security Devices<\/h3>\n\n <p>Twelve volts is the legacy workhorse of security and low-power electronics. Door access readers, electric strikes, CCTV cameras, PIR occupancy sensors \u2014 these devices built their ecosystems around 12V decades ago, and the supply chain still defaults to it. If your project is access-control-heavy, 12V will feel natural.<\/p>\n\n <p>The trade-off is distance. At 12V, a 10-amp load running through 1.5 mm\u00b2 copper wire drops roughly 0.7 volts over a 15-meter round-trip. By 20 meters, the voltage at the far end has sagged enough that a door lock may chatter or a camera may brown out during IR night-mode switching. If your cable runs are short and your loads predictable, 12V works fine. If not, keep reading.<\/p>\n\n <h3>24V DC \u2014 The Industry Standard for Building Controllers and Sensors<\/h3>\n\n <p>Twenty-four volts is where building automation lives. DDC controllers from every major manufacturer \u2014 Johnson Controls, Honeywell, Siemens \u2014 run on 24V DC. So do field sensors (temperature, humidity, CO\u2082, pressure), damper and valve actuators, relay modules, and BACnet\/IP gateways. A single medium-sized commercial floor might have two to four 24V DIN-rail power supplies in its control cabinet, each feeding a different zone or subsystem.<\/p>\n\n <p>Why 24V won is straightforward. It stays within SELV (Safety Extra-Low Voltage) limits defined by IEC 60364-4-41, which means no shock hazard during maintenance. It also pushes roughly twice the power over the same copper as 12V for the same percentage voltage drop. At 10 amps on 1.5 mm\u00b2 wire, a 24V circuit reaches a 5% drop at roughly 40 to 50 meters \u2014 double the reach of 12V. For a floor-level control cabinet feeding devices across a 30-meter wing, 24V gets the job done without intermediate boosters.<\/p>\n\n <p>If you have to pick one voltage without knowing the full device list yet, pick 24V. The ecosystem is broad enough that you will almost certainly find compatible equipment.<\/p>\n\n <h3>48V DC \u2014 Long-Distance Runs and PoE Infrastructure<\/h3>\n\n <p>Forty-eight volts is less common in traditional BAS but growing fast, driven by Power over Ethernet. Under the 802.3bt (PoE Type 4) standard, a single Cat6A cable can deliver up to 100 watts at 48V. That is enough to power a small controller, a touch panel, and a handful of sensors through one RJ45 jack. For new construction where the ICT contractor is already pulling structured cable, PoE-based BAS can eliminate separate power wiring entirely.<\/p>\n\n <p>Outside PoE, 48V also makes sense for very long DC distribution runs. Think of a central equipment room feeding devices across a 200-meter warehouse or a high-rise riser where voltage drop would cripple a 24V system. The trade-off is device compatibility. The 48V BAS ecosystem is still thin compared to 24V, and the equipment that does exist carries a price premium. Unless PoE or long-haul distribution is a hard requirement, 24V remains the safer default.<\/p>\n<img decoding=\"async\" src=\"https:\/\/www.omch.com\/wp-content\/uploads\/2026\/07\/Gemini_Generated_Image_a6vl4ia6vl4ia6vl.webp\" alt=\"Switching Power Supply for Building Automation\" class=\"bd-post-image\" loading=\"lazy\">\n \n <div class=\"bp-3-quickref bd-reveal\">\n <div class=\"bp-3-volt\">\n <div class=\"bp-3-volt-icon\"><svg width=\"20\" height=\"20\" viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><polygon points=\"13 2 3 14 12 14 11 22 21 10 12 10 13 2\"\/><\/svg><\/div>\n <div class=\"bp-3-volt-label\">12V DC<\/div>\n <div class=\"bp-3-volt-desc\">Access control, security cameras, short cable runs<\/div>\n <\/div>\n <div class=\"bp-3-volt\">\n <div class=\"bp-3-volt-icon\"><svg width=\"20\" height=\"20\" viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><polygon points=\"13 2 3 14 12 14 11 22 21 10 12 10 13 2\"\/><\/svg><\/div>\n <div class=\"bp-3-volt-label\">24 V CC<\/div>\n <div class=\"bp-3-volt-desc\">DDC controllers, sensors, actuators \u2014 the BAS standard<\/div>\n <div class=\"bp-3-volt-badge\">RECOMMENDED<\/div>\n <\/div>\n <div class=\"bp-3-volt\">\n <div class=\"bp-3-volt-icon\"><svg width=\"20\" height=\"20\" viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><polygon points=\"13 2 3 14 12 14 11 22 21 10 12 10 13 2\"\/><\/svg><\/div>\n <div class=\"bp-3-volt-label\">48V DC<\/div>\n <div class=\"bp-3-volt-desc\">PoE infrastructure, long-distance distribution<\/div>\n <\/div>\n <\/div>\n\n <h2>Power Sizing \u2014 How to Calculate Load and Avoid the “Undersized PSU” Trap<\/h2>\n\n <p>Power sizing seems like arithmetic: add up all the device wattages, pick the next PSU up, done. In practice, three factors regularly trip up even experienced engineers. Accounting for them upfront is the difference between a control cabinet that runs for a decade and one that generates monthly service calls.<\/p>\n\n <h3>Step 1 \u2014 Add Up Your Real Load, Device by Device<\/h3>\n\n <p>Start with a load schedule. For each device on the PSU, write down its nominal power draw, then tally the total. Here are realistic ranges for common BAS equipment based on currently available mid-range product lines:<\/p>\n\n <div class=\"table-wrapper\">\n <table>\n <thead><tr><th>Tipo de dispositivo<\/th><th>Typical Power Draw (24V DC)<\/th><\/tr><\/thead>\n <tbody>\n <tr><td>DDC controller (mid-size, ~32 I\/O points)<\/td><td>8\u201315 W<\/td><\/tr>\n <tr><td>Touch panel \/ operator display (7\u201310 inch)<\/td><td>10\u201325 W<\/td><\/tr>\n <tr><td>Field sensor (temperature, humidity, CO\u2082)<\/td><td>1\u20133 W each<\/td><\/tr>\n <tr><td>Damper\/valve actuator (spring-return, 10 Nm)<\/td><td>5\u201315 W (running), 0 W (holding, if mechanical)<\/td><\/tr>\n <tr><td>Door electric strike<\/td><td>10\u201330 W (pulse)<\/td><\/tr>\n <tr><td>IP surveillance camera (PoE or 24V)<\/td><td>5\u201315 W<\/td><\/tr>\n <tr><td>BACnet router \/ protocol gateway<\/td><td>3\u20138 W<\/td><\/tr>\n <\/tbody>\n <\/table>\n <\/div>\n\n <p>The trap is sensor count. Five sensors at 2 W each is 10 W \u2014 trivial. Two hundred sensors across a campus is 400 W, and that number often only surfaces after the PSU is already installed. Build your load schedule early, and keep it updated as the device list evolves.<\/p>\n\n <h3>Step 2 \u2014 Add 20\u201330% Headroom (and Know When to Add More)<\/h3>\n\n <p>The standard rule is to multiply total load by 1.2 to 1.3 and select a PSU at or above that number. A 168 W total (7 A at 24V) points to a 240 W (10 A) unit, not a 200 W (8.3 A) one.<\/p>\n\n <p>Three scenarios push that multiplier higher:<\/p>\n\n <p><strong>Motor and solenoid inrush.<\/strong> An electric strike or spring-return actuator can draw two to three times its running current for the first 100 to 200 milliseconds. If multiple actuators fire simultaneously during a fire-alarm sequence, the instantaneous load spike can trip the PSU’s over-current protection \u2014 and every controller on that rail reboots mid-event.<\/p>\n\n <p><strong>High-temperature cabinets.<\/strong> Most DIN-rail PSUs publish a derating curve. A typical unit, such as the Mean Well NDR-240 series, delivers 100% of rated power at 40\u00b0C ambient, derates to roughly 80% at 50\u00b0C, and falls to about 60% at 60\u00b0C. A sealed NEMA enclosure on a sun-exposed rooftop in summer can easily reach 50\u00b0C inside. If your load is 180 W and the PSU is rated 240 W at 25\u00b0C, you might think you have 25% headroom. At 50\u00b0C inside the cabinet, the real headroom is closer to zero.<\/p>\n\n <p><strong>Future expansion.<\/strong> Building automation systems grow over time. A floor renovation adds 30 more VAV controllers. A security upgrade adds more cameras. If you size to the exact load today, you will be replacing PSUs within three to five years. The labor to swap a DIN-rail unit in a live cabinet costs far more than the extra 30% capacity you could have bought upfront.<\/p>\n\n <h3>Step 3 \u2014 Separate Critical Loads from Noisy Loads<\/h3>\n\n <p>Here is a failure pattern that generates more service calls than any undersized PSU: a door controller reboots every time the electric strike fires. The cause is not a software bug or a faulty strike. It is a voltage sag caused by putting a high-inrush inductive load on the same PSU rail as sensitive electronics.<\/p>\n\n <p>When a relay coil or solenoid de-energizes, the collapsing magnetic field generates a reverse voltage spike that can reach 10 to 20 times the nominal coil voltage. Without a flyback diode, that spike dumps straight onto the DC rail as conducted EMI \u2014 enough to brown out or reset a microcontroller-based DDC.<\/p>\n\n <p>The fix is simple and costs almost nothing at design time. Dedicate one PSU to control and communication devices (DDC, sensors, gateways, displays). Put switching loads (locks, relays, solenoid valves) on a separate PSU. A third PSU for auxiliary loads like LED indicators, cabinet lighting, and convenience outlets is optional but keeps troubleshooting cleaner. Label each PSU’s output with its served function. The technician who opens this cabinet at 2 AM will thank you.<\/p>\n\n <h2>DIN Rail, Panel Mount, or Enclosed? Matching Form Factor to Your Installation<\/h2>\n\n <p>By this point, you have chosen a voltage and calculated your power budget. Now the question is physical: what does the PSU look like and where does it live?<\/p>\n\n <p>For building automation control cabinets, DIN-rail mounting \u2014 specifically TS35\/7.5 profile \u2014 is the default and the right answer in most cases. A DIN-rail PSU snaps onto the same rail as your circuit breakers, relays, and terminal blocks, making the cabinet layout clean and modular. When a unit fails \u2014 and eventually, every PSU fails \u2014 swapping it takes 30 seconds. Unscrew two terminals, release the DIN clip, snap in the replacement, re-terminate. No drilling, no brackets, no downtime beyond a power cycle.<\/p>\n\n <p>Panel-mount or chassis-mount PSUs are larger, typically 200 W and above, and bolt directly to the backplane of a cabinet. They make sense when you need high power density in a single unit \u2014 say, a 480 W supply feeding an entire floor’s worth of controllers \u2014 or when you are building a custom enclosure that does not have DIN rail at all. The trade-off is serviceability. Replacing a panel-mount unit means tools, time, and possibly shutting down adjacent equipment to access the mounting screws.<\/p>\n\n <p>Enclosed or IP-rated PSUs are for locations where the environment, not the load, drives the decision. A corridor ceiling junction box. A parking garage equipment closet. An outdoor air-handling unit. Look for IP65 or better with a sealed cable gland entry and conformally coated PCBs. Expect to pay two to three times the price of an equivalent DIN-rail unit. Budget for it early, because retrofitting enclosures after the fact is expensive.<\/p>\n\n <h2>Efficiency, Thermal Performance, and What “Industrial-Grade” Really Means<\/h2>\n\n <p>Efficiency ratings on a PSU datasheet \u2014 89%, 91%, 93% \u2014 look like small differences, and on a single unit, they are. The gap opens up at scale. A building with 50 DIN-rail PSUs running 24\/7, each dissipating an extra 10 W of heat because of a 3% efficiency gap, burns an additional 4,380 kWh per year. That is enough to matter on both the energy bill and the cooling load. Over a 10-year equipment lifecycle, that delta can pay for a significant fraction of the PSU budget itself.<\/p>\n\n <p>Thermal design matters more than the headline efficiency number. Fan-cooled PSUs achieve higher power density in a smaller chassis, but fans have bearings, and bearings wear out. In a sealed BAS control cabinet where nobody opens the door for five years, a failed fan means a PSU cooking itself to death with no audible warning. Convection-cooled, fanless designs cost slightly more per watt but eliminate the single most common mechanical failure point. For building automation, where reliability trumps density, fanless is the right default.<\/p>\n\n <p>Component quality is where the real difference hides \u2014 the gap between a PSU rated for commercial use and one built to an industrial standard. The clearest signal is the electrolytic capacitor temperature rating. Capacitors are the life-limiting component in any switching PSU. Their electrolyte dries out over time, and heat accelerates that process exponentially. A capacitor rated at 105\u00b0C, operated at a 40\u00b0C internal ambient, can outlast an 85\u00b0C-rated capacitor by a factor of three to four, following the Arrhenius rate law that governs electrolyte degradation. Manufacturers who specify Japanese-brand capacitors \u2014 Rubycon ZLH series, Chemi-Con KZE, Nichicon PW \u2014 are making a bill-of-materials choice that directly extends field life. Look for capacitor brand and temperature rating in the datasheet. If neither is published, ask.<\/p>\n\n \n <div class=\"bp-1-stat bd-reveal\">\n <div class=\"bp-1-stat-numeral\">3\u20134\u00d7<\/div>\n <div class=\"bp-1-stat-caption\">\n <div class=\"bp-1-stat-label\">Longer field life<\/div>\n <div class=\"bp-1-stat-desc\">105\u00b0C-rated capacitors outlast 85\u00b0C equivalents by a factor of three to four, following the Arrhenius rate law. This bill-of-materials choice directly extends PSU service life.<\/div>\n <\/div>\n <\/div>\n\n <h2>Protection Features and Certifications \u2014 What to Look for on the Spec Sheet<\/h2>\n\n <p>Protection features are the PSU’s first line of defense. Certifications are the third-party vote of confidence. Both need to be on your checklist. A PSU with great specs but no independent safety testing is a liability waiting for an inspector to find it.<\/p>\n\n <h3>The Five Essential Protection Features Every BAS PSU Should Have<\/h3>\n\n <p>Every DIN-rail PSU marketed for industrial use will claim to have protections. What matters is what happens when they activate \u2014 particularly whether the unit recovers automatically or latches off.<\/p>\n\n <div class=\"table-wrapper\">\n <table>\n <thead><tr><th>Protecci\u00f3n<\/th><th>What It Prevents<\/th><th>What to Check<\/th><\/tr><\/thead>\n <tbody>\n <tr><td>Over-Voltage Protection (OVP)<\/td><td>Output voltage runaway that fries downstream electronics<\/td><td>Trip threshold and response time<\/td><\/tr>\n <tr><td>Over-Current \/ Overload Protection (OCP)<\/td><td>Thermal damage from sustained overcurrent<\/td><td>Constant-current limiting vs. hiccup mode<\/td><\/tr>\n <tr><td>Short-Circuit Protection (SCP)<\/td><td>Catastrophic failure from wiring faults or load shorts<\/td><td><strong>Auto-recovery<\/strong> vs. latch-off (auto-recovery is mandatory for unattended cabinets)<\/td><\/tr>\n <tr><td>Over-Temperature Protection (OTP)<\/td><td>Thermal runaway in high-ambient or fan-failure scenarios<\/td><td>Auto-restart after cooling<\/td><\/tr>\n <tr><td>Surge Protection<\/td><td>Damage from lightning-induced or switching transients on the mains input<\/td><td>Compliance with IEC 61000-4-5; Class 3 (2 kV line-to-ground) is adequate for most indoor BAS; Class 4 (4 kV) for outdoor-fed panels<\/td><\/tr>\n <\/tbody>\n <\/table>\n <\/div>\n\n <p>SCP recovery behavior is the one to scrutinize. A latch-off PSU that trips on a momentary wiring short will sit dead until someone physically cycles power. In a locked BAS cabinet in a remote mechanical room, that could be days. Auto-recovery with hiccup-mode retry \u2014 where the PSU attempts to restart every few seconds until the short clears \u2014 is the only acceptable behavior for unattended building systems.<\/p>\n\n <h3>UL 508, UL 1310, EN 62368, CE \u2014 Making Sense of the Certification Alphabet<\/h3>\n\n <p>Certifications are a language, and most spec sheets assume you speak it. Here is a translation table for the marks that actually matter in building automation procurement:<\/p>\n\n <div class=\"table-wrapper\">\n <table>\n <thead><tr><th>Certification<\/th><th>Regi\u00f3n<\/th><th>What It Covers<\/th><th>Why It Matters for BAS<\/th><\/tr><\/thead>\n <tbody>\n <tr><td>CE<\/td><td>EU \/ EEA<\/td><td>Baseline safety + EMC compliance (self-declared by manufacturer)<\/td><td>Minimum barrier to entry for European projects; without it, customs clearance may be denied<\/td><\/tr>\n <tr><td>UL 508<\/td><td>North America<\/td><td>Industrial control equipment safety<\/td><td>Required by most US electrical inspectors for control panel acceptance; covers the PSU as a component within a larger industrial control panel<\/td><\/tr>\n <tr><td>UL 1310<\/td><td>North America<\/td><td>Class 2 power units \u2014 output limited to \u226460 V DC, \u22648 A, and \u2264100 VA per channel<\/td><td>Critical where fire safety codes require power-limited circuits (plenum spaces, historic buildings, healthcare); a Class 2 output means no conduit required for low-voltage wiring<\/td><\/tr>\n <tr><td>EN 62368-1<\/td><td>EU (IEC 62368 globally)<\/td><td>Safety for audio\/video, IT, and communication equipment \u2014 the modern successor to EN 60950<\/td><td>Increasingly adopted as the baseline safety standard for BAS equipment with communication interfaces; hazard-based rather than prescriptive<\/td><\/tr>\n <\/tbody>\n <\/table>\n <\/div>\n\n <p>For export projects, the safest combination is CE + UL. UL can be substituted with ETL or CSA \u2014 all three are OSHA-recognized NRTL marks in the US. If your project includes plenum-rated spaces or ungrounded historical buildings, UL 1310 Class 2 compliance is the specification that will keep the electrical inspector from flagging your installation.<\/p>\n\n <h3>How to Verify Certifications Are Real (Not Just Logos on a Webpage)<\/h3>\n\n <p>Certification fraud is common enough in the industrial power supply market that a five-minute verification step is worth the effort. UL certifications can be checked through the UL Product iQ database at productiq.ul.com. Enter the manufacturer’s name or UL file number and confirm the certificate is active and covers the specific model you are buying. For CE marking, request the EU Declaration of Conformity document. A legitimate DoC lists the specific harmonized standards the product was tested against \u2014 for example, EN 55032:2015 + A1:2020 for EMC emissions. A CE logo without an accompanying DoC is not a valid CE mark. Reputable suppliers provide these documents on request. Hesitation is a red flag.<\/p>\n\n \n <div class=\"bp-cta-mid bd-reveal\">\n <div class=\"bp-cta-mid-icon\"><svg width=\"24\" height=\"24\" viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"var(--accent)\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><circle cx=\"12\" cy=\"12\" r=\"10\"\/><path d=\"M9.09 9a3 3 0 015.83 1c0 2-3 3-3 3\"\/><line x1=\"12\" y1=\"17\" x2=\"12.01\" y2=\"17\"\/><\/svg><\/div>\n <div class=\"bp-cta-mid-text\">Matching PSU specs across an entire BAS project takes time. If you need a second pair of eyes on your device list, our selection engineers can help.<\/div>\n <a class=\"bp-cta-mid-btn\" href=\"https:\/\/www.omch.com\/es\/contact\/\" target=\"_self\">Request Selection Support<\/a>\n <\/div>\n\n <h2>Load Separation and Wiring \u2014 Simple Practices That Prevent Field Failures<\/h2>\n<img decoding=\"async\" src=\"https:\/\/www.omch.com\/wp-content\/uploads\/2026\/07\/Gemini_Generated_Image_kb1g7zkb1g7zkb1g.webp\" alt=\"Switching Power Supply for Building Automation\" class=\"bd-post-image\" loading=\"lazy\">\n\n <p>Most PSU selection guides end after the spec sheet. But a perfectly chosen power supply, installed poorly, will generate the same service calls as the wrong one. Two real-world patterns show why installation practice belongs in the selection conversation.<\/p>\n\n <p><strong>Pattern 1: the 2 PM controller reboot.<\/strong> A new access control system on a commercial office floor works flawlessly \u2014 except every weekday at roughly 2 PM, when all four door controllers on the east wing reboot simultaneously. After three site visits and two controller replacements, the root cause surfaces. All controllers share one PSU with the electric strikes. And 2 PM is when the afternoon cleaning crew badges in through the loading dock, triggering all four strikes in rapid succession. Each strike’s inductive kickback drags the DC rail low enough to brown out the controller MCUs.<\/p>\n\n <p><strong>Pattern 2: the ghost sensor.<\/strong> A bank of CO\u2082 sensors on a VAV system reports readings that drift 200 to 300 ppm every afternoon, then recover overnight. Sensors are replaced twice. The culprit is not the sensors. It is the PSU’s output ripple, which increases as the cabinet temperature rises through the afternoon. An oscilloscope on the 24V rail shows 300 mV of ripple at 4 PM versus 80 mV at 8 AM. The sensor’s analog front end cannot reject the noise.<\/p>\n\n \n <div class=\"bp-2-diagnosis bd-reveal\">\n <div class=\"bp-2-case\">\n <div class=\"bp-2-case-head\">\n <span class=\"bp-2-case-icon\"><svg width=\"20\" height=\"20\" viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><path d=\"M10.29 3.86 1.82 18a2 2 0 001.71 3h16.94a2 2 0 001.71-3L13.71 3.86a2 2 0 00-3.42 0z\"\/><line x1=\"12\" y1=\"9\" x2=\"12\" y2=\"13\"\/><line x1=\"12\" y1=\"17\" x2=\"12.01\" y2=\"17\"\/><\/svg><\/span>\n <span class=\"bp-2-case-title\">Pattern 1: The 2 PM Reboot<\/span>\n <\/div>\n <div class=\"bp-2-case-cause-label\">Root cause:<\/div>\n <div class=\"bp-2-case-cause-text\">Controllers sharing a PSU with electric strikes \u2014 inductive kickback from simultaneous strike activation browns out the MCUs.<\/div>\n <\/div>\n <div class=\"bp-2-case\">\n <div class=\"bp-2-case-head\">\n <span class=\"bp-2-case-icon\"><svg width=\"20\" height=\"20\" viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><polyline points=\"22 12 18 12 15 21 9 3 6 12 2 12\"\/><\/svg><\/span>\n <span class=\"bp-2-case-title\">Pattern 2: The Ghost Sensor<\/span>\n <\/div>\n <div class=\"bp-2-case-cause-label\">Root cause:<\/div>\n <div class=\"bp-2-case-cause-text\">PSU output ripple increasing with cabinet temperature \u2014 the sensor’s analog front end cannot reject the noise on the DC rail.<\/div>\n <\/div>\n <\/div>\n\n <p>Three rules prevent most of these failures at zero additional hardware cost:<\/p>\n\n <ul>\n <li>Separate control from switching loads. DDC controllers, sensors, gateways, and communication modules share one PSU. Electric strikes, solenoid valves, relay coils, and motorized actuators share a different PSU. The two rails are electrically independent. No single switching event can disturb the control electronics.<\/li>\n <li>Calculate voltage drop for every cable run over 30 meters. At 24V and 10A on 1.5 mm\u00b2 copper, a 60-meter round trip drops roughly 7V \u2014 nearly 30% of the nominal voltage, enough that end-of-line devices will malfunction. Either upsize the cable (2.5 mm\u00b2 halves the drop for the same length) or add a local PSU at the far end.<\/li>\n <li>Label every PSU output. A piece of heat-shrink or a clip-on cable marker with “DDC-Zone-3” or “Lock-PSU-East” saves the next technician 80% of their troubleshooting time. In a cabinet with four identical-looking DIN-rail PSUs, unlabeled outputs turn a 10-minute swap into a two-hour tracing exercise.<\/li>\n <\/ul>\n\n <h2>The Buyer’s Selection Checklist \u2014 A Framework for Comparing Switching PSUs Objectively<\/h2>\n\n <p>You have worked through voltage, power, form factor, efficiency, protections, certifications, and installation practice. The following table pulls every dimension into a single checklist. Print it, keep it with your project specs, and run every candidate PSU through it before ordering.<\/p>\n\n <div class=\"table-wrapper\">\n <table>\n <thead><tr><th>#<\/th><th>Selection Dimension<\/th><th>What to Check<\/th><th>Your Project<\/th><\/tr><\/thead>\n <tbody>\n <tr><td>1<\/td><td>Tensi\u00f3n de salida<\/td><td>12V \/ 24V \/ 48V \u2014 matches all connected devices<\/td><td><\/td><\/tr>\n <tr><td>2<\/td><td>Total Power<\/td><td>Sum of all device loads \u00d7 1.2\u20131.3 headroom<\/td><td><\/td><\/tr>\n <tr><td>3<\/td><td>Montaje<\/td><td>DIN rail (TS35\/7.5) \/ panel-mount \/ enclosed (IP-rated)<\/td><td><\/td><\/tr>\n <tr><td>4<\/td><td>Eficacia<\/td><td>\u226585% at 230V full load (\u226590% preferred for 24\/7 operation)<\/td><td><\/td><\/tr>\n <tr><td>5<\/td><td>Cooling<\/td><td>Convection (fanless) \u2014 strongly preferred for sealed cabinets<\/td><td><\/td><\/tr>\n <tr><td>6<\/td><td>Protections<\/td><td>OVP, OCP, SCP with auto-recovery, OTP, surge (IEC 61000-4-5 Class 3+)<\/td><td><\/td><\/tr>\n <tr><td>7<\/td><td>Certificaciones<\/td><td>CE + UL 508 or UL 1310 Class 2 (per target market and installation environment)<\/td><td><\/td><\/tr>\n <tr><td>8<\/td><td>Temperatura de funcionamiento<\/td><td>At least \u221210\u00b0C to +60\u00b0C; review derating curve at your cabinet’s expected ambient<\/td><td><\/td><\/tr>\n <tr><td>9<\/td><td>Load Separation<\/td><td>Control electronics on a dedicated PSU, switching loads on a separate PSU<\/td><td><\/td><\/tr>\n <tr><td>10<\/td><td>Supplier Verification<\/td><td>UL certificate verifiable at productiq.ul.com; EU DoC available; third-party test reports provided on request<\/td><td><\/td><\/tr>\n <\/tbody>\n <\/table>\n <\/div>\n\n <p>Selection is not a one-time decision. Device lists change during commissioning. A client adds a floor. A security consultant specifies more cameras. The PSU you sized at design development may be marginal by final acceptance. Build in enough headroom that a late addition does not force a re-order. When you do need to source PSUs that check every box on this list, look for suppliers who make their certifications and derating curves publicly available rather than buried behind a sales contact form. Transparency in the datasheet is a reasonable proxy for transparency in the product.<\/p>\n\n <p><em>For projects requiring DIN-rail switching power supplies across the 15 W to 480 W range \u2014 with CE, RoHS, and ISO 9001 certifications backed by 38 years of manufacturing experience \u2014 OMCH ‘s full switch-mode power supply catalog is available online, with product selection support for matching specifications to project requirements.<\/em><\/p>\n\n \n <div class=\"bp-cta-end bd-reveal\">\n <div class=\"bp-cta-end-icon\"><svg width=\"32\" height=\"32\" viewbox=\"0 0 24 24\" fill=\"none\" stroke=\"currentColor\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"><rect x=\"2\" y=\"4\" width=\"20\" height=\"16\" rx=\"2\"\/><path d=\"M22 7-10 10L2 7\"\/><\/svg><\/div>\n <div class=\"bp-cta-end-title\">Match Your PSU Specs to Your Project<\/div>\n <div class=\"bp-cta-end-subtitle\">Send us your device list. Our application engineers review it against 15 W\u2013480 W DIN-rail options with CE, RoHS, and ISO 9001 certifications \u2014 and recommend the right fit.<\/div>\n <a class=\"bp-cta-end-btn\" href=\"https:\/\/www.omch.com\/es\/contact\/\" target=\"_self\">Get Specifications Matched<\/a>\n <\/div>\n\n <h2>References<\/h2>\n\n <ol>\n <li>UL Standards & Engagement. “UL 1310 \u2014 Standard for Class 2 Power Units.” <a href=\"https:\/\/standardscatalog.ul.com\/ProductDetail.aspx?productId=UL1310\">https:\/\/standardscatalog.ul.com\/ProductDetail.aspx?productId=UL1310<\/a><\/li>\n <li>IEC. “IEC 61000-4-5: Electromagnetic Compatibility (EMC) \u2014 Part 4-5: Testing and Measurement Techniques \u2014 Surge Immunity Test.” <a href=\"https:\/\/webstore.iec.ch\/publication\/4264\">https:\/\/webstore.iec.ch\/publication\/4264<\/a><\/li>\n <li>Mean Well. “NDR-240 Series \u2014 240W Industrial DIN Rail Power Supply Datasheet.” <a href=\"https:\/\/www.meanwell.com\/productPdf.aspx?i=28\">https:\/\/www.meanwell.com\/productPdf.aspx?i=28<\/a><\/li>\n <li>IEEE. “802.3bt-2018 \u2014 IEEE Standard for Ethernet Amendment 2: Power over Ethernet over 4 Pairs.” <a href=\"https:\/\/standards.ieee.org\/standard\/802_3bt-2018.html\">https:\/\/standards.ieee.org\/standard\/802_3bt-2018.html<\/a><\/li>\n <li>OMCH. “Switch Mode Power Supply \u2014 DIN-Rail and Enclosed Series.” <a href=\"https:\/\/www.omch.com\/es\/switch-mode-power-supply\/\">https:\/\/www.omch.com\/switch-mode-power-supply\/<\/a><\/li>\n <li>OMCH. “OMCH \u2014 Industrial Automation Components Manufacturer.” <a href=\"https:\/\/www.omch.com\/es\/\">https:\/\/www.omch.com\/<\/a><\/li>\n <\/ol>\n <\/article>\n<\/div>\n\n<\/body><\/html>\n\n\n\n\n<p><\/p>","protected":false},"excerpt":{"rendered":"<p>Switching Power Supply for Building Automation \u2014 The Practical Selection Guide Why Switching Power Supplies Are the Backbone of Building Automation Every DDC controller, every access control panel, every bank of sensors scattered across a commercial building \u2014 they all run on low-voltage DC power. The device that converts incoming AC mains into that clean, […]<\/p>","protected":false},"author":4,"featured_media":12038,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_seopress_robots_primary_cat":"none","_seopress_titles_title":"Switching Power Supply for Building Automation \u2014 The Practical Selection Guide","_seopress_titles_desc":"Practical selection guide for switching power supplies in building automation. Learn how to choose voltages, size power budgets, and prevent field failures.","_seopress_robots_index":"","footnotes":""},"categories":[79],"tags":[],"class_list":["post-12035","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-mmlblog"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.omch.com\/es\/wp-json\/wp\/v2\/posts\/12035","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.omch.com\/es\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.omch.com\/es\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.omch.com\/es\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.omch.com\/es\/wp-json\/wp\/v2\/comments?post=12035"}],"version-history":[{"count":1,"href":"https:\/\/www.omch.com\/es\/wp-json\/wp\/v2\/posts\/12035\/revisions"}],"predecessor-version":[{"id":12041,"href":"https:\/\/www.omch.com\/es\/wp-json\/wp\/v2\/posts\/12035\/revisions\/12041"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.omch.com\/es\/wp-json\/wp\/v2\/media\/12038"}],"wp:attachment":[{"href":"https:\/\/www.omch.com\/es\/wp-json\/wp\/v2\/media?parent=12035"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.omch.com\/es\/wp-json\/wp\/v2\/categories?post=12035"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.omch.com\/es\/wp-json\/wp\/v2\/tags?post=12035"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}