By Kent · Lock Depot Staff Writer

One maglock on one door is a simple power job: a supply, a battery, done. A building with eight fail-safe locks that all have to drop the instant the fire panel trips is a different job entirely, and it's the one where integrators end up stacking a power supply, a handful of separate relay boards, and a fire alarm interface module into a cabinet that was never sized for all three. The Altronix AL600ULACM exists to collapse that stack into one box.

What's actually inside the box

The AL600ULACM converts a 115VAC 60Hz line into eight independently controlled 12VDC or 24VDC outputs, each fuse-protected and each individually selectable as fail-safe or fail-secure. Total continuous supply current is 6 amps, with a maximum battery charge current of 0.7 amp for backup. That's the power supply and charger half of the name. The "ACM" half is an integrated access power controller: each of the eight outputs is triggered independently by a signal from an access control system, card reader, keypad, push button, or PIR, so the same box that's feeding the locks is also the thing switching them on and off per door.

What earns this unit a spot in a multi-door fail-safe job specifically is the built-in fire alarm disconnect. It's individually selectable per output, and when the fire alarm system activates, every output wired into that disconnect drops power and releases its lock for emergency egress, without a separate interface module translating the fire panel's signal into something the lock power understands. AC and DC status are supervised with dedicated LED indicators, and both AC fail and low-battery conditions report through Form C dry contacts rated at 1 amp, 28VDC, so the panel monitoring the room knows the difference between "locked" and "silently dead."

When you don't need the whole box

Not every job needs a new power supply. If the building already has adequate 12 or 24VDC power on hand and the actual gap is the switching and fire-alarm-disconnect logic, the standalone Altronix ACM8CB does that half alone. It takes one 12 to 24 volt AC or DC input and converts it into eight independently controlled, Class 2-rated, PTC-protected outputs, each triggered the same way, by an open-collector sink or a dry contact from an access control system, card reader, keypad, or PIR, and routes power out to maglocks, electric strikes, or other locking hardware. Spec the ACM8CB when the power already exists and only the control logic is missing; spec the AL600ULACM when both the power and the control logic need to be sourced together.

Sizing the job, not just the box

Eight outputs sounds like eight doors, but the real constraint is current draw, not output count. Add up the actual amperage every lock, reader, and auxiliary device on the circuit will draw, including inrush on a maglock at startup, against the unit's 6-amp continuous rating before assuming all eight outputs can run at full load simultaneously. A building with eight lightly-loaded strikes fits comfortably; eight high-draw maglocks running at once on one AL600ULACM will not. Where the load runs close to the limit, splitting the doors across two units, or pairing the AL600ULACM with a separate Altronix supply for the heavier loads, is the fix that doesn't show up as a brownout six months after the inspection sign-off.

Battery backup sizing follows the same logic. The 0.7-amp charge rate is enough to maintain a reasonably sized battery bank through normal cycling, but it isn't a fast-charge circuit, so if the building's outage pattern is frequent short interruptions rather than rare long ones, confirm the battery has time to recover between events rather than slowly draining across a string of short outages.

Where the box actually lives

The AL600ULACM is a panel-mount unit meant for a locked electrical or telecom closet, not an open equipment rack in a public corridor. Plan for a cabinet with enough depth for the battery it's charging, since most jobs pair it with a sealed lead-acid backup battery sized to carry the connected load through a code-required outage window, commonly 4 to 24 hours depending on the occupancy and local AHJ requirements. Label every output at the terminal block the day it's wired, not months later during a service call. On an eight-output box feeding eight different doors, an unlabeled terminal is the single most common reason a maintenance tech disconnects the wrong lock while troubleshooting an unrelated one.

Grounding and surge protection matter more here than on a single-door supply, precisely because a fault on this unit takes down every door wired into it at once rather than just one opening. Follow Altronix's grounding guidance for the enclosure and incoming AC, and don't share the circuit with equipment prone to electrical noise if the building's access control panel is sensitive to it.

Common questions

Can the AL600ULACM power both fail-safe and fail-secure locks at the same time?

Yes. Each of the eight outputs is independently selectable, so a building with a mix of fail-safe maglocks on egress doors and fail-secure strikes elsewhere can run both from the same unit without cross-wiring workarounds.

Do I still need a separate fire alarm interface module?

No, not for the outputs wired into the AL600ULACM's built-in fire alarm disconnect. That's the point of the integrated feature: it reads the fire alarm trip and drops the selected outputs directly, without a translator module in between.

What's the real difference between the AL600ULACM and the ACM8CB?

The AL600ULACM includes its own power supply and battery charger built in; the ACM8CB is the access-control switching logic alone and needs an external DC power source already in place. Pick based on whether the job needs new power, new switching, or both.

How do I know if 6 amps is enough for my building?

Add the rated current draw of every device that will run on the unit's outputs at once, including a margin for inrush current on maglocks at power-up, and compare that total against the 6-amp continuous rating. If it's close, split the load across two units rather than running at the edge of the rating daily.

Does this unit work with an existing third-party access control panel?

Yes, since each output is triggered by a generic dry contact or open-collector signal rather than a proprietary protocol, which is what makes it compatible with most access control panels, card readers, and standalone keypads already in the field.

For sizing a single-door power supply rather than a multi-door controller, see Altronix LPS3C24X: Power Supply for a Maglock Door. The rest of Altronix's power and access-control line is on the Altronix hub.