Access Control Systems

An electric door strike is used to regulate the function of securely locking doors. The use of an electric door strike provides access control for a door, which can be configured to either fail-secure or fail-safe settings. Meaning, should there not be power, the strike can be set to either be open (to allow egress) or closed (to secure the facility). It is this type of functionality that has made electric door strikes the single best seller among access control devices.

AC versus DC electric door strike

The main distinction in an electric door strike is whether a door will use alternating current (AC) or direct current (DC). The two types are not interchangeable when wiring them into a building, so knowing the difference is very important.

Perhaps the most telling difference between the two is when the strike is in the open position. In AC doors there is a buzz while DC strikes will remain silent. The buzzing sound is caused by the pushing and pulling of the locking mechanism to create a mechanical buzzing noise.

If a DC strike is powered by an AC power supply, it could cause problems. A typical malfunction resulting from using an AC power supply with a DC lock is the lock failing to open properly. Direct current strikes reply on having constant power for opening and closing, not the on again, off again power associated with SC supplies. Conversely, using an AC strike with a DC power supply might seem to work at first, but this will not last. The locking mechanism in an AC strike has lower resistance, thus heat buildup is not dissipated quickly enough. This could cause the metal within the lock to heat up and eventually fail.

To prevent any breakdowns in your security locking system, make sure that you know what type of current you are using before setting up a door strike. In some cases, a manufacturer will make a strike that works with both AC and DC currents for better compatibility. These units are by far, more flexible, but also more expensive.

The price of a door strike is reflective of its quality. Prices can range from as little as $20-$350, depending upon the strength, voltage, and security features of the lock. If a lock is going to be used often, it is best to invest in a more expensive strike for a longer lifespan. Replacing a $20 lock every six months for several years is more expensive than buying a $300 lock from the onset, and there is the added deficit associated with not having a working lock between replacements.

To help you further refine your search, here are a few characteristics of AC and DC strikes.

AC strike

• Trine 12V AC Fail Safe Strike: $330.22
• Adams Rite 24 V AC Strike: $149.39

DC strike

• HES Heavy Duty Strike - $239.00
• CRL Adams Rite Aluminum 24 V DC Strike - $180.00

AC/DC strike

• Rutherford Controls L65U AC/DC Strike - $101.00
• Dyna-Lock 1661-24 24 V AC/DC Strike - $143.00

Professional installation is always advised when dealing with electricity and electrical components. Another aspect of installing new electric strikes is underwriter regulations governing insurance. In some cases, commercial, industrial, and even residential insurance might require an electric strike be installed by a certified professional. Check with your insurance company before you attempt to install the strike yourself.