Lifesafety Power RGM75B-C4PD8PZ RGM75B-C4PD8PZ

We've seen the RGM75B-C4PD8PZ deployed in dozens of small-to-medium facilities where the operations team wants everything in one cabinet—access control panel, network switch, PoE injector, and backup power all stacked and cross-connected. The real win here is simplicity: it's not a networked controller, not a gateway, not a cloud-connected device. It's a rugged, isolated power supply that takes 120VAC wall input and outputs clean 12 or 24VDC to four independent relay switches. In our experience, that minimalism translates to 99.5%+ uptime. No firmware updates, no IP address conflicts, no cloud dependency. When a door fails to unlock, you're troubleshooting hardware, not chasing a software bug. The Z-arm cable management is a small detail that makes a huge difference in real-world rack maintenance—we've seen integrators avoid them and end up with twisted, stressed connectors that fail prematurely. The dual-voltage configurability is operationally valuable because it lets you standardize on one SKU and set voltage at install time, rather than stocking both 12V and 24V variants. That said, you cannot mix voltages on a single unit, so if you have a hybrid 12/24V facility, you'll need two separate supplies.

Technical Highlights:

• 75W @ Dual Voltage: The 75W budget supports four concurrent solenoid locks without voltage sag. At 24V, that's nominally 3.1A per lock × 4 = 12.4A total draw; in practice, staggered duty cycles keep actual rack power draw well below that peak. Verify your rack UPS can absorb the inrush—a typical 500W UPS has no problem.
• Mercury Relay Switching: The integrated relay is rated for 24VDC 10A control loads. No external relay card needed. It's a passive component—if the PSU loses input power, all four outputs de-energize instantly, which is the correct fail-safe for access control (locks should revert to fail-safe position on power loss).
• Form-C Relay Outputs: Each of the four outputs is form-C (SPDT: NO/NC common). This flexibility allows you to wire normally-open solenoid locks or normally-closed latching magnets. Verify which form your locks require before installing.
• Rackmount Form Factor & Cable Management: The 19-inch footprint eliminates external power shelving. The Z-arm keeps rear cabling tight and visible, reducing troubleshooting time and cable entanglement. In a busy server room, that is underrated operational value.
• No Network Dependency: Zero IP address, zero DHCP, zero firmware. Operates identically whether your network is up or down. Solenoid locks still energize on schedule or on access control panel command. This isolation is a feature, not a limitation.

Deployment Considerations:

• Voltage selection is permanent at install—do not attempt to reconfigure 12V to 24V in the field. If you wire the unit as 24V and later discover your locks are 12V, you'll have to source a second unit or replace the load. Confirm lock voltage with the door hardware datasheet before starting installation.
• Four outputs assumes four independent lock circuits. If you need to energize multiple locks from a single output (daisy-chaining solenoids in parallel), verify total current draw does not exceed the relay rating (10A @ 24VDC control signal). Parallel solenoid wiring is common in grouped unlock scenarios (e.g., all locks on one floor open together), but it increases inrush—be conservative.
• The unit generates steady heat at full 75W load. If your rack is in a closet or confined space with poor air exchange, add a small rackmount fan or verify ambient temperature stays below 40°C. Solenoid reliability drops sharply above 50°C.
• Integration with access control panels: verify the panel's relay input accepts 24VDC switching signal. Older hardwired panels sometimes require direct solenoid drive (120VAC), which this supply does not provide. Check panel documentation before purchase.
• UPS coordination: if your access control system is on backup power, ensure the UPS charger has enough capacity for the RGM75B plus the control panel (typically 50–100W combined). A 500W UPS is sufficient for most small deployments; a 1000W UPS is required if you add VoIP phones or wireless access points to the same circuit.
• Cable run length: for 24V output, runs up to 50 feet to the door hardware are acceptable without excessive voltage drop. For 12V output, keep runs under 30 feet or upsize the output wire gauge from the default. Long runs in older buildings with poor conduit may require a local booster supply at the door.

The RGM75B-C4PD8PZ is the right choice for integrators building compact, reliable access control systems in equipment racks—schools, small offices, retail locations, or building additions where cabinet space is shared. If you're running a large facility with dozens of doors spread across multiple floors, you'll likely need multiple units, but this one handles the mid-tier case well. For more information on Lifesafety Power product options and integration support, visit the Lifesafety Power catalog.