Altronix T2428100CP220 Open-Frame AC Transformer in Wall-Mount Enclosure
Overview
The Altronix T2428100CP220 is a 100VA open-frame transformer designed to power electronic security, access control, and surveillance equipment from a 220VAC mains source. It delivers either 24VAC at 4A or 28VAC at 3.5A — the two voltage rails most commonly required by commercial-grade access control panels, door strike power supplies, and ancillary security devices. If your installation runs on 220V mains (international sites, industrial facilities, or regions outside North America's 120V standard), this is the transformer spec to evaluate before you size anything else in the power stack. Browse the full Altronix power products catalog for the broader transformer and power supply lineup.
The T2428100CP220 ships pre-mounted inside Altronix's BC100 wall-mount enclosure — a steel indoor cabinet measuring 7.5"W × 8.5"H × 3.5"D with combination knockouts for 1/2" and 3/4" conduit entry. This means you're not sourcing a separate enclosure or field-fabricating a mounting solution; the unit arrives ready to wall-hang and wire.
Key Features
- Dual Output Voltage Selection (24VAC / 28VAC): Wiring for 24VAC delivers 4A of supply current; wiring for 28VAC delivers 3.5A. The 28VAC tap is particularly useful for longer wire runs to electric strikes or mag-locks where a slightly elevated voltage compensates for line drop — you get device-level voltage closer to 24V at the load end without running heavier gauge wire.
- 220VAC Input with Fused Protection: The input accepts 220VAC at 50 or 60Hz, drawing 0.5A. An inline fuse rated 3.5A/250V provides fused input protection — if a fault condition drives excess current through the primary, the fuse interrupts before the transformer or downstream equipment is damaged. On a panel powering access hardware, that's the difference between a fuse replacement and replacing a door controller.
- 110VA System Requirement: The unit's system AC input VA requirement is 110VA. When you're sizing the circuit breaker or UPS feeding this transformer, budget at least 110VA of capacity at the panel — underspecifying the upstream circuit is one of the more common field mistakes on multi-transformer installations.
- BC100 Wall-Mount Enclosure Included: The steel BC100 enclosure is rated for indoor wall mounting. Combination knockouts accept both 1/2" and 3/4" conduit, giving you flexibility on conduit sizing without field drilling. The enclosure dimensions (7.5"W × 8.5"H × 3.5"D) fit comfortably in a utility closet or IDF room without requiring dedicated rack space.
- Green Grounding Lead: A dedicated green grounding lead is included. On a transformer feeding security hardware, a proper chassis ground is not optional — it's both a safety requirement and a noise-reduction measure that matters when the transformer is co-located with low-voltage signal wiring.
- Commercial Operating Temperature Range: Rated 0°C to 49°C (32°F to 120°F) operating, -20°C to 70°C storage. The 49°C ceiling covers most mechanical room and IDF environments. If your enclosure is in an unconditioned space that regularly exceeds 49°C (desert climates, outdoor mechanical rooms), this unit is not the right fit — look for a higher-rated alternative in the power supply category.
- Compact Footprint, Known Weight: At 6.5 lbs product weight (7.1 lbs shipping), the T2428100CP220 is manageable for a single-person installation on a wall stud or backing plate. No lift equipment or second installer required for the mounting phase.
Integration & Compatibility
The T2428100CP220 is intended as a primary AC power source for electronic power supplies and end-point security devices — not as a standalone power supply with regulated DC output. Downstream devices should include their own AC-to-DC rectification and regulation if DC power is required. This transformer is a natural upstream component for access control power supplies and panel installations that accept 24VAC input, common in legacy and commercial-grade Altronix power supply modules.
Conduit entry via 1/2" or 3/4" knockouts supports both EMT and flexible conduit runs. The enclosure is not rated for outdoor use — installations must be in a conditioned or semi-conditioned interior space within the 0–49°C operating window. For outdoor or harsh-environment transformer needs, consult the Altronix product line for appropriately rated alternatives.
When planning the installation, pair this transformer with an appropriate UPS or battery backup solution upstream if the downstream access control system requires holdover during a mains outage — the T2428100CP220 itself provides no battery or backup capability.
Frequently Asked Questions
Q: What input voltage does the T2428100CP220 require?
A: The T2428100CP220 requires 220VAC input at 50 or 60Hz, drawing 0.5A. It is not designed for 120VAC North American standard circuits — verify your mains voltage before installation.
Q: Can I select between 24VAC and 28VAC output on the T2428100CP220?
A: Yes. The transformer offers two output options: 24VAC at 4A or 28VAC at 3.5A. The output voltage is determined by which secondary winding tap you wire to — consult the Altronix installation instructions for wiring details.
Q: Is the enclosure included with the T2428100CP220, or does it need to be purchased separately?
A: The BC100 wall-mount indoor enclosure is included with the T2428100CP220. The enclosure measures 7.5"W × 8.5"H × 3.5"D and includes combination knockouts for 1/2" and 3/4" conduit entry.
Q: What is the fuse rating on the T2428100CP220?
A: The inline input fuse is rated 3.5A at 250V. It provides fused input protection on the primary side of the transformer.
Q: Is the T2428100CP220 suitable for outdoor installations?
A: No. The BC100 enclosure is rated for indoor wall-mount use only. The operating temperature range is 0°C to 49°C. Outdoor or harsh-environment applications require a different enclosure solution.
Q: What upstream circuit capacity does the T2428100CP220 require?
A: The system AC input VA requirement is 110VA. Size your upstream circuit breaker or UPS accordingly — a circuit that cannot sustain 110VA will cause nuisance trips or undervoltage conditions.
The T2428100CP220 fills a specific gap in 220V-mains access control installations: you need a transformer that speaks 220VAC on the primary and outputs the 24VAC or 28VAC that commercial security panels and power supplies expect, all within a ready-to-mount enclosure. The 100VA rating at 4A on the 24V tap is enough headroom for a mid-size access control power supply plus a few ancillary loads — not a large multi-door rack, but a solid single-panel or zone-level power source.
Technical Highlights:
- Dual Output Taps: 24VAC at 4A or 28VAC at 3.5A — the 28V tap gives you a voltage cushion for wire-run voltage drop; by the time you reach the load, you're delivering closer to 24V on longer runs without upsizing wire gauge.
- Inline Fuse (3.5A/250V): Primary-side fused input protection means a fault on the primary side opens the fuse rather than stressing the transformer windings — a straightforward fault-protection mechanism that keeps the repair cost to a fuse replacement.
- BC100 Enclosure Included: The 7.5" × 8.5" × 3.5" steel enclosure with 1/2" and 3/4" combo knockouts eliminates the need to source a separate housing — a real time saver when you're commissioning a closet installation on a tight schedule.
Deployment Considerations:
- Confirm your mains is 220VAC (50 or 60Hz) before ordering — this transformer has no primary tap for 120VAC; installing it on a 120V circuit will result in half-voltage output and underperformance of all downstream devices.
- The 49°C (120°F) operating ceiling is the spec to watch in mechanical rooms or server closets with poor airflow — transformer heat dissipation is approximately 50 BTU/hr, which adds to room thermal load in tight spaces.
The T2428100CP220 is the right specification for international facility deployments — European offices, Middle Eastern data centers, or Latin American commercial buildings — where the local mains is 220V and the access control hardware downstream expects standard 24VAC Altronix-ecosystem power. It is not a fit for domestic US 120V panels or for high-door-count systems requiring multi-ampere capacity beyond the 4A output ceiling.
