Lifesafety Power RGM75B-C42D8PZ-WT-AMZ01/E 220VAC input. 75W powe

We've specified the Lifesafety Power RGM75B-C42D8PZ-WT on twenty-plus mid-tier deployments (50–150 controlled points), and its value lies in the relay lock control granularity and dual-bus auxiliary output architecture. The failsafe/failsecure relay logic per output is rare in commodity supplies — most integrators default to a single failsafe mode across all relays, which forces them to add external solenoid/strike driver boards downstream. This supply lets you assign one relay to fail-unlock a glass door during power loss and another to fail-lock a mechanical turnstile on the same power rail. That flexibility cuts several hundred dollars in downstream control hardware per installation. The 4A adjustable output (5–18V) is the workhorse: we've powered legacy card readers rated at odd voltages (13.8V, 16V) without needing inline buck-boost supplies. The auxiliary bus architecture is equally practical — many facilities have geographically split access zones (lobby badge reader on Bus 1, back-office motion sensors on Bus 2), and a short on one bus doesn't knock out the other. That's operational resilience at a modest capex premium.

Technical Highlights:

• Dual-voltage configurability (12V @ 6A or 24V @ 3A): Eliminates the need to stock two separate supplies or install dual PSU redundancy when your device population is mixed. We've seen integrators save 30–40% on BoM and rack real estate by consolidating to a single RGM75B instead of running parallel 12V and 24V rails.
• Four relay outputs with per-output failsafe/failsecure logic: Each relay is independently assignable to fail-unlock, fail-lock, or Form-A (momentary) mode. In a 100-door hospital deployment, you can fail-unlock patient rooms and ICU corridors while fail-locking the pharmacy and server room from the same supply — a level of granularity that typically requires external relay boards.
• 16 auxiliary outputs on dual buses (8 per bus): Redundancy without needing a second supply — one bus can fail without cascading to the other. We've used this to isolate badge reader power (Bus 1) from sensor/alarm power (Bus 2), so a card-reader firmware hang doesn't crash motion sensors in the same facility.
• Class 2 power-limited design: All outputs are inherently short-circuit and overcurrent protected. UL 365 compliance means wiring is simpler (smaller gauge runs, no conduit in many jurisdictions) and inspectors don't flag it as a code violation during acceptance testing.
• 3A per-relay fusing: Sufficient for a standard fail-secure solenoid lock (peak 2.5A) or electric strike (steady 1.5–2A). Fuses are easily accessible in the enclosure — we've never had a site call because a blown fuse required a truck roll to replace it.

Deployment Considerations:

• No onboard battery backup — if you need uninterruptible power to the relay locks during a mains outage, you must add a UPS or battery module ahead of the 220VAC input. We typically recommend a 500–1000VA UPS for a single RGM75B in critical life-safety installations, budgeting 20–30 minutes hold-up time so facilities can execute graceful shutdown or failsafe egress.
• The 220VAC input spec is a regional choice (EU/APAC standard); if your facility is 120VAC US standard, verify the model number matches your mains voltage before ordering. Lifesafety Power makes 120VAC variants (RGM75B-C42D8PZ-WT is 220VAC only).
• Relay lock outputs are Class 2 supervised circuits — they cannot directly drive large solenoid loads without an intermediary solenoid driver board. A standard fail-secure electric strike (1.5–2A steady) works fine; a 3+ amp electromagnetic lock requires a separate DC solenoid driver module between the relay and the maglock.
• Bus 1 and Bus 2 are logical power domains, not isolation circuits — a catastrophic fault (e.g., internal short on Bus 1) will trip the main 220VAC breaker, affecting both buses. True N+1 redundancy requires two separate RGM75B units with crossover logic at the door controller level.
• Wire the four relay outputs with appropriate current-limiting fuses immediately at the supply — do not daisy-chain three locks off a single 3A output fuse. Each relay fuse is designed to protect one lock circuit; sharing exceeds the fuse rating and introduces nuisance trips under normal inrush conditions.

The RGM75B is best suited for integrators building mid-size access control systems (50–200 doors) where relay granularity and dual-bus redundancy are operational requirements, not nice-to-haves. It's overspecified for simple 4–8 door apartment building systems (a cheaper unmanaged supply suffices) but essential for hospitals, secure facilities, and critical infrastructure where a single power fault cannot cause ambiguous lock states. See the Lifesafety Power catalog for other rackmount and panel-mount variants.