Altronix SMP5PMCTX220 Supervised Power Supply with Large Cabinet
Overview
The Altronix SMP5PMCTX220 is a supervised power supply designed for commercial security power supplies installations where accountability matters as much as raw output. Running on either 115VAC or 230VAC input, it delivers a selectable 12VDC or 24VDC output at up to 4A continuous — enough to drive a meaningful load of access control readers, door hardware, or ancillary camera power in a single enclosure. The supervision contacts set it apart from unsupervised alternatives: separate Form C relays for both AC failure and low battery give your monitoring system discrete, actionable fault signals rather than a silent failure.
The large steel cabinet (13.5" × 13" × 3.25") has room to house one or two 7AH/12VDC batteries, so you're not hunting for a separate battery enclosure or compromising on standby time. At 8.2 lb. product weight, it's wall-mountable by a single installer without needing a second set of hands.
Key Features
- Universal AC Input (115VAC / 230VAC): A single SKU works across North American 115VAC/60Hz panels and international 230VAC/50-60Hz installations — no separate transformer or voltage variant required. Input current draw is 2.5A at 115VAC and 1A at 230VAC, so budget your circuit load accordingly before sizing breakers.
- Selectable 12VDC or 24VDC Output: Field-configurable output voltage means you can match the supply to your downstream hardware at installation time rather than stocking two SKUs. Select 12VDC for most IP cameras and legacy readers, or 24VDC for door strikes, maglocks, and controllers that require it.
- 4A Continuous Output: Four amps continuous is a real working budget — not a peak rating. Size your load at 80% of that (3.2A) for thermal headroom and you have plenty of margin for a mixed reader-plus-door-hardware zone.
- Form C AC Failure Contact: The dedicated Form C relay for AC failure lets your monitoring panel or access control system detect a mains loss event as a discrete digital input — not just infer it from voltage sag. This is the difference between a supervised and an unsupervised supply in practice: you know when the grid is down, not just when the battery runs out.
- Form C Low Battery Contact: A separate Form C low-battery relay provides early warning before the supply drops output, giving monitoring systems time to dispatch a response before access control goes offline. Two independent supervision contacts — not one shared relay — mean you can distinguish AC loss from battery degradation in your panel programming.
- 1 or 2 × 7AH Battery Support: The enclosure accommodates one or two 7AH/12VDC batteries. Doubling battery capacity extends standby time proportionally — useful in facilities where code or policy requires 4- or 8-hour backup durations. Batteries are not included; source standard 7AH/12V sealed lead-acid units locally.
- Large Steel Cabinet (13.5" × 13" × 3.25"): The oversized enclosure provides real wiring room for field terminations — a practical detail that speeds commissioning and simplifies future service calls. Adequate internal space also accommodates cable management and avoids the cramped, heat-retaining installations common with compact enclosures.
- 0°C to 49°C Operating Range: Covers normal indoor mechanical room, IDF closet, and above-ceiling installations without derating. Storage temperature extends from -20°C to 70°C, so units can be warehoused in unconditioned space without concern.
- 85% RH Humidity Tolerance: Suitable for damp utility rooms and parking garage interiors where condensation is a periodic risk, provided the enclosure stays closed during high-humidity events.
Integration & Compatibility
The SMP5PMCTX220 fits cleanly into broader Altronix power distribution architectures. Its Form C supervision contacts wire directly to standard access control panel inputs — most major platforms accept Form C dry contacts for supervisory zones, so integration requires no additional interface modules. If you're designing a multi-door system, pair this supply with a compatible Altronix multi-output relay board to distribute the 4A budget across individual door circuits with per-circuit overcurrent protection. For camera-specific power distribution, consult the PoE switch selection for IP cameras that draw power over Ethernet rather than from a centralized low-voltage supply. Where low-voltage centralized power is the architecture — common in retrofit access control in older buildings — this supply's voltage selectability and cabinet capacity make it a practical single-enclosure solution.
Frequently Asked Questions
Q: Can the SMP5PMCTX220 supply both 12VDC and 24VDC simultaneously?
A: No. The output voltage is selectable — 12VDC or 24VDC — but only one voltage is available at a time. Configure it at installation to match the voltage requirement of your downstream devices.
Q: How many batteries does the SMP5PMCTX220 support, and what size?
A: The enclosure supports one or two 7AH/12VDC sealed lead-acid batteries. Batteries are not included with the unit and must be sourced separately. Using two batteries doubles available standby capacity.
Q: Does the SMP5PMCTX220 work on 230VAC international power?
A: Yes. The supply accepts either 115VAC/60Hz or 230VAC/50-60Hz input, making it suitable for both domestic and international installations without any hardware modification.
Q: What do the Form C supervision contacts signal?
A: There are two separate Form C relay contacts: one signals AC mains failure, and one signals a low battery condition. These wire to monitoring panel inputs to provide discrete fault annunciation for each condition independently.
Q: What is the maximum continuous output current of the SMP5PMCTX220?
A: The unit is rated for 4A continuous maximum output. For thermal reliability in sustained-load installations, plan your load budget at approximately 80% of that — around 3.2A.
Q: What are the enclosure dimensions of the SMP5PMCTX220?
A: The enclosure measures 13.5" × 13" × 3.25". Shipping dimensions are 15" × 13.875" × 4.75", and the product weighs 8.2 lb.
The SMP5PMCTX220 is the unit I spec when an integrator needs real supervision accountability in a single enclosure — specifically, the dual Form C contacts for AC failure and low battery as separate discrete signals. That distinction matters at commissioning time when you're programming panel inputs: you want the monitoring system to know the difference between a grid outage and a battery that's degrading, not just that something is wrong with power.
Technical Highlights:
- Dual Form C Supervision: Two independent relay contacts — one for AC mains loss, one for low battery — allow panel programming to distinguish fault types without adding an external supervision module. Most access control panels accept these as standard normally-closed supervisory loops.
- Dual Battery Capacity: Supporting one or two 7AH/12VDC batteries in the same cabinet is a genuine design advantage. For installations requiring extended standby under UL or local AHJ requirements, doubling to two batteries is a same-enclosure upgrade rather than a second housing and conduit run.
- Universal Input Voltage: The 115VAC/230VAC dual-input design at 2.5A and 1.0A respectively means the same SKU ships to a domestic commercial job or an international facility — a minor detail that matters when you're managing a mixed portfolio of domestic and export projects from the same inventory.
Deployment Considerations:
- The 4A continuous rating is the actual working ceiling — not a marketing peak. Wire your load budget at 3.2A (80%) and factor in inrush from any magnetic locks or relay coils on the circuit; inrush can briefly exceed steady-state draw by 3–5× and should be verified against the output stage's transient tolerance in the full Altronix datasheet.
- Batteries are not included. Source 7AH/12VDC sealed lead-acid units separately, and verify physical dimensions will fit the cabinet — some aftermarket 7AH cells run slightly taller than nominal and will bind against the enclosure lid.
This supply is well-suited to small-to-midsize access control installations — four-to-eight door systems in commercial office, light industrial, or multi-tenant buildings — where a single supervised supply per riser closet keeps the BOM clean and the monitoring panel inputs unambiguous.
