Altronix T2428175C220 175VA 24/28VAC Transformer
The Altronix T2428175C220 is a 175VA transformer designed for 220VAC input with selectable 24VAC or 28VAC output, housed in a compact CAB4 wall-mount enclosure. Built for security installations in regions where 220VAC primary power is standard, this unit delivers regulated low-voltage AC power to access control panels, electric locks, CCTV auxiliary supplies, and alarm system components. The dual-output configuration eliminates the need to stock two SKUs, and the enclosed form factor integrates cleanly into cabinet-mounted or wall-adjacent power distribution schemes without exposing high-voltage or transformer components to site traffic.
Key Features
- 175VA Capacity: Handles combined loads across multiple access points and CCTV cameras without voltage sag or thermal stress during peak demand cycles.
- 220VAC Input: Direct compatibility with standard European, Asian, and Middle Eastern utility power (no step-down or buck transformer required).
- Selectable 24/28VAC Output: Single unit accommodates both 24VAC legacy devices and 28VAC high-current lock applications; jumper-based selection at installation.
- CAB4 Enclosure: Compact wall or cabinet-mount form factor (approximately 4″ × 4″ footprint) fits retrofit installations and equipment closets without occupying floor or rack space.
- Lifetime Limited Warranty: Factory coverage against defects ensures long-term reliability in unattended outdoor and indoor security applications.
- UL Listed & CE Marked: Meets North American and European safety standards; acceptable to integrators and facility managers for mission-critical power distribution.
The T2428175C220 bridges the gap between high-voltage utility power and low-voltage security device requirements without the bulk or cost of industrial-grade isolation transformers. At 175VA, the unit is sized for small-to-mid-scale deployments: a typical door-entry system with two electric strikes (48-60W combined), plus a 4-channel PoE midspan injector drawing 90W, consumes ~140VA at peak, leaving headroom for future expansion or short transient spikes. Unlike switching power supplies, this transformer provides inherent isolation and surge protection through magnetic coupling; the secondary side is galvanically isolated from the primary 220VAC, reducing risk of ground-loop noise on analog camera feeds or access-control signaling lines.
Installation flexibility is a key operational benefit. The selectable output voltage (24/28VAC) means integrators can standardize on a single transformer SKU and configure it on-site based on existing lock hardware or client preference. In mixed-equipment environments—where older 24VAC mag-locks coexist with newer 28VAC fail-safe strikes—this eliminates the need to source and manage two separate transformer models. The CAB4 enclosure is DIN-compatible in many security rack systems, and its wall-mount bracket allows flush installation in equipment rooms or utility closets adjacent to cable runs, reducing wire run length and associated voltage drop over long cable distances.
Total cost of ownership is favorable for long-term deployments. Unlike high-efficiency switching supplies that may require replacement every 7-10 years if exposed to temperature extremes or power transients, transformer-based designs have no electrolytic capacitors to degrade and no switch-mode circuitry to fail. Altronix transformers are rated for 20+ years in typical HVAC-controlled environments and even longer in benign climates. When paired with a UPS battery backup (common in access-control system architectures), the transformer's low switching noise and stable waveform ensure cleaner battery charging and longer cell lifespan versus noisey switching supplies.
The T2428175C220 complies with UL 2089 (Power Supplies) and EN 60950-1 (IEC safety standards), making it acceptable for specifying into enterprise access-control and CCTV integrations across regulated industries (healthcare, financial, education). If your deployment includes ONVIF-compliant cameras or access-control systems requiring Altronix power distribution, this transformer works seamlessly with Altronix battery backup modules (AL24, AL24E) and DIN-rail power-distribution blocks (PoE4C, D4C, etc.), creating a unified, tested power architecture that most NVR vendors and panel manufacturers already integrate.
Marty AllisonPerspective based on aggregated IP Security Depot and affiliated engineering team experience.
We've installed hundreds of Altronix transformers across European, Middle Eastern, and African sites where 220VAC is the norm. The T2428175C220 is a reliable workhorse for small-to-mid access-control systems and mixed CCTV/intercom deployments. What sets it apart from generic industrial transformers is the combination of compact CAB4 form factor, dual-output flexibility, and proven compatibility with Altronix backup power modules and DIN-rail distribution systems. Unlike switching supplies that can introduce high-frequency noise on video or data lines, this transformer provides true galvanic isolation and a clean, low-noise secondary waveform — something that matters more than it should on analog camera circuits or older access-panel serial lines. The lifetime warranty is genuine (not marketing; Altronix honors out-of-warranty repairs on decade-old units if failure is manufacturing defect), and the enclosure design keeps moisture and dust off the transformer core without requiring active cooling or forced ventilation.
Technical Highlights:
- 175VA at Full Load: Delivers approximately 7.3A at 24VAC or 6.3A at 28VAC. On a typical access-control panel drawing 4-5A continuous plus 2-3A transient for lock strike, you stay well within the safe operating margin. Transformers run cooler at 70% loading than at 95%; this unit is sized to avoid thermal stress on 24/7 deployments.
- Galvanic Isolation: The secondary is completely isolated from mains ground, eliminating ground-loop hum (50Hz mains harmonic) that can appear as a visible 50Hz bar pattern on analog camera feeds or RF interference on access-control keypads. This is why transformer-based supplies are still preferred over switching units in video-heavy or RF-sensitive sites.
- Selectable Output (24/28VAC): Configured via internal jumper at time of installation. Most modern electric strikes prefer 28VAC (holds more reliably under transient load spikes); older mag-locks spec 24VAC. The single-SKU approach reduces purchasing overhead and on-site inventory for integrators managing multiple customer types.
- CAB4 Wall or DIN Mount: The compact form factor fits into existing 4-inch wall boxes or DIN-rail clips without retrofitting cable trays or utility boxes. We've retrofit dozens of sites where floor or rack space was at a premium, and the transformer mounts flush without causing cable strain or heat-dissipation issues.
- UL 2089 & EN 60950-1 Compliance: Meets North American and European safety requirements, which means it's acceptable in most jurisdictional electrical codes without special permitting. Switching supplies often require additional UPS or surge protection; this transformer's isolation stage is inherent protection.
Deployment Considerations:
- 175VA is the practical ceiling for a single access point with two heavy-duty mag-locks plus auxiliary loads. If your site has more than two simultaneous strike events (e.g., turnstile + door lock + emergency exit unlock), calculate peak load carefully or consider a larger 24VA unit (e.g., Altronix T2428250C). We've seen sites pull 200+ VA on emergency unlock, which would cause secondary sag and delayed lock release on this unit.
- Cable run distance from transformer to the furthest load matters. If your access panel is 150+ feet away, voltage drop on the 24VAC secondary can be noticeable (0.5-1V per 100 feet depending on wire gauge). Size your secondary wiring at 12 AWG or larger for long runs; this is not a switching supply where tight wiring is forgiving.
- The dual output (24/28VAC selection) is a one-time decision at installation. You cannot switch between 24 and 28 on the fly without opening the enclosure. Label the configuration clearly on the transformer or in your as-built documentation so future technicians don't accidentally reconfigure it and cause lock failures.
- 220VAC input is non-negotiable. If your site has 110/120VAC utility (North America) or 240VAC (Australia), this transformer will not function. Verify primary voltage against your site electrical plan before shipment.
- Heat dissipation is passive (no cooling fan). In poorly ventilated electrical closets or outdoor junction boxes, transformer temperature can rise 10-20°C above ambient. If your enclosure location exceeds 40°C ambient, verify thermal margins with Altronix technical support or consider adding ventilation slats to the CAB4 enclosure.
The T2428175C220 is the right choice for international sites (220VAC regions) deploying small-to-mid access-control systems, intercom backups, or CCTV auxiliary power where clean isolation and dual-output flexibility matter more than compact switching-supply economics. For integrators supporting multi-site portfolios with mixed 24/28VAC device inventories, the single-SKU approach simplifies project logistics. Explore more Altronix transformers and power distribution products to round out your security power architecture.
