Power sources can be AC (alternating current) or DC (direct current). In the context of electrified hardware, AC power is intended for intermittent duty (like momentary unlocking for an apartment main entry) while DC power is used for continuous duty (like an access control system for an office building’s main entry doors.) Most applications in today’s access control systems are DC supply.
However, it is important to consider if the device requires a 12-voltage or 24-voltage power source. Depending on the manufacturer and model, they can be:
- 12-volt only
- 24-volt only
- 12-volt OR 24-volt
- 12-volt TO 24-volt
Let’s take an example. An HES 9600 electric strike can draw power from either a 12-volt or a 24-volt power source. It draws current equal to 0.45 amps at 12-volt, but only 0.25 amps at 24-volt. These numbers indicate a requirement of about half an amp at 12-volt but just one-quarter of an amp at 24-volt. How is this useful? If you start adding multiple devices, it stands to reason that if you are able to run them all on 24-volt, you can run more devices off of a power supply that supplies 24-volt than one that supplies 12-volt.
In our listed example, let’s say we want to run two HES 9600 electric strikes off of a 1-amp power supply. If you run them at 12-volt, you would use 0.90 amps – almost all of it – but if you run them at 24-volt, you would only be using 0.50 amps, which would allow you to add a third strike, if desired. Please note that it is not recommended to exceed 75-80% of the total current of the power supply; so in this example, don’t add a fourth strike.
Special thanks to Tony Warren, Security Integration Project Manager at LaForce, for contributing this useful answer! More information about our electrified hardware products – a growing necessity! – can be found here: LaForce Inc. Electrified Hardware.