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Integrate External Power with the AC41 in EMEA
Integrate External Power with the AC41 in EMEA

Learn how to use external devices to power maglocks and crash bars in EMEA

Updated over a week ago

The Verkada AC41 access controller can provide power to specific locks, as long as their inrush current does not exceed 350mA at 24V or 700mA at 12V.

Note: The inrush current used to initially magnetize the lock can exceed the operating current and is sometimes not listed in the data sheets. If the requirements exceed the power that the AC41 can provide, the door is unable to lock and the AC41 could become damaged.


  • Use an external access power controller (APC) dry setup when you wire a crash bar.

  • Use an external APC dry setup when you wire up an electromagnetic lock(maglock).

  • Ensure that power is disconnected from the AC41 and lock hardware before wiring readers and other devices. Failure to do so can damage the AC41.

How the integration works

Use an APC

This option uses an external APC, such as the Altronix AL600ULACM (widely available in the US) or the Hfeng Access Control Power Supply Control Switch (available in EMEA, as shown below).

The AC41 runs dry (the toggle on the left side of the cassette is configured to None), and connects the NO and COM ports to IN and GND, respectively. (The IN port is sometimes labeled as PUSH, as shown above). The APC then uses its NC and COM ports to connect to the maglock.

Create a manual release in case of an emergency

Because maglocks are constantly powered, fault tolerance needs to be built into the system. This process permits an exit in case of any emergency, without relying solely on the system.

  1. Install a Glass Break button, in the vicinity of the request to exit (REX), that you can smash in case of an emergency; effectively breaking the circuit and allowing for an exit.

    Required: You need to install this button in series with the APC and maglock.

  2. Depending on local regulations, you might need to set up the fire alarm system to automatically drop power to the maglocks. To do this, wire the Fire Alarm Control Panel (FACP) Trigger Input in parallel with the AC41's connections to the APC.

  3. In the event of the FACP detecting a fire, you can configure it to set off the auxiliary relay (or series of relays) and instruct the APC to drop power.

Note: The Verkada AC41 does not have a dedicated FACP input. This needs to be wired into the APC. The location of the FACP Trigger Input might vary depending on the APC used. It is the responsibility of the installer to read the appropriate documentation and understand the proper wiring configuration.

Use a regular power supply

In case APC is not available, you can use a regular power supply unit (PSU), such as the Fortessa DC Boxed Switch Mode PSU, and an additional 12V/24V relay module (as shown below).

The required wiring is shown below (note the Glass Break required for manual egress in case of emergency, if the system is not responsive):

AC42 and AC62 Considerations

Most of the recommendations listed in this article also apply to the second-generation controllers. However, the new AC42 and AC62 controllers come with terminal blocks (as opposed to cassettes), resulting in a much higher resistive load (2A at 24V or 4A at 12V). This means that you can use a regular PSU to power a lock up to 2A (at 24V), with an APC only needed over that limit. This is because it has a separate power relay that does not touch (thus damage) the access controller.

With this in mind, here are the 3 ways to power a lock using AC42 or AC62:

Lock Criteria

Power Lock Method

Locks under 350mA @ 24V

The controller powers them wet. No third-party device is required.

Locks between 350mA and 2A @ 24V

Use a regular PSU in series with the lock and AC unit (Glass Break recommended for NC circuits; see diagram below), or just a regular APC (as per the previous diagrams).

Locks over 2A @ 24V

Use an APC (just as you would for an AC41 running a lock dry).

Related resources

Need help? Contact Verkada Support

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