As the name indicates, surface-mount electric strikes are mounted onto the surface of the jamb without cutting an opening to accommodate the mechanism. They are designed to operate with rim exit devices whose strikes have been surface applied.
Rim exit devices are surface-mounted exit devices mounted onto the secured side of an outswinging door in order to permit free egress. The latching mechanism for most rim exit devices is a Pullman bolt, which swings out and in from the center case. Because the Pullman bolt swings out instead of extending out, latch movement is in an arced shape to accommodate the swing. Depending upon the manufacturer and the application, rim exit devices can have either a ½” or ¾” throw Pullman bolt.
Surface-mount electric strikes can be used to secure exit devices mounted onto wood, composite, hollow metal or aluminum storefront doors. Electric strikes come in different thicknesses in order to accommodate different rim exit device applications.
Trine’s 4800 and 4801 Surface Mount Electric Strike models have ¾” thick bodies to accommodate different bolt configurations. A 1/8” thick spacer is included for installations requiring mounting the strike closer to the exit device lock case. The Trine 4801 was developed to accommodate Corbin Russwin SecureBolt™ and Yale SquareBolt® equipped exit devices. The 4800 was developed for Pullman Bolt-equipped exit devices.
To expand the surface-mount product line, Trine introduced the 4850 Surface-Mount Electric Strike with a ½” thick body, designed for those applications that have minimal distance between the center case and the jamb. Since the 4850 does not have a back plate, the Pullman Bolt has a full ½” depth. To accommodate different Pullman Bolts and installations, Trine includes a ¼” and 1/8” thick spacers in order to have proper clearance between the electric strike and the center case.
A standard mount rim exit device will have the latch in close proximity to the strike. This way, when the door is closed and the latch is secured, the gap is minimal, ensuring the door is secured. For this reason, there is very limited amount of space between the strike mounted onto the jamb and the exit device cover.
For this article, I was invited to the installation of a Trine 4850 Surface Mount Electric Strike onto an aluminum frame. The 4850 is a Grade 1 electric strike with the capability of automatically adjusting an input of 11 to 28VDC. For 12VDC operation, the pull-in requires .500 Amps while hold requires .178 Amps. For 24VDC, the pull-in requires .255 Amps while hold requires .084 Amps. The 4850 electronics are designed with surge and kickback protection.
The Trine 4850 will be used to control access on the aluminum-glass storefront door equipped with a rim exit device. To our advantage, the building has a gable roof with ample standup headroom in the attic. The door was located beneath the ridge, making it relatively easy to run the wiring down to the jamb and connect the electric strike. From there, an HID reader was installed on the exterior wall adjacent to the lock side of the door. The power supply was installed in the computer room.
To resist unauthorized access, anti-vandal trim with astragal was installed onto the exterior to protect the cylinder and the device’s Pullman Bolt. The stainless steel trim’s coating covers the pull handle area. The anti-vandal trim is Americans With Disabilities Act (ADA) compliant.
Electronic access will be controlled by the use of proximity identification cards. A decision was made not to install a release button at the desk just inside the office. Instead, a doorbell was previously installed to notify the receptionist if some unauthorized individual wanted access. Having a glass aluminum door gives the receptionist the choice to permit or restrict access.