Camden CM-400 Series Single Gang 1-5/8" Mushroom Pushbutton with 'PUSH TO LOCK', Black Text

Yes. The CM-400 is built on a single gang stainless steel faceplate measuring 4-1/2"H x 2-3/4"W x 1-3/4"D (114mm x 70mm x 44mm). That 1-3/4 inch depth is behind the plate, so you need a box deep enough to take the switch body. If your opening has a narrow mullion or hollow metal frame instead, Camden builds the same button on a narrow plate at 4-1/2" x 1-3/4" x 1-3/4", and a wide 4-1/2" x 4-1/2" plate for a two gang cover.

Momentary. The contact closes only while the mushroom button is held in, then springs back. That makes it right for signalling an access control panel, maglock controller, or electric strike to lock or release, and wrong for anything that needs a latched-on state. Contact rating is 6 A at 30 VDC, so it switches low voltage DC control circuits directly rather than line voltage.

The nearest match is the Dortronics 5210 Series exit release, which uses a 1-9/16 inch diameter red mushroom push button mounted on a single gang plate. The Camden CM-400 uses a 1-5/8 inch (40mm) diameter mushroom button, also single gang, with an 18 gauge stainless steel faceplate and a momentary switch rated 6 A @ 30 VDC. Button diameters are within a sixteenth of an inch of each other, so both drop into a standard single gang box in the same way. The difference is text: the Camden plate is marked PUSH TO LOCK in black, while the Dortronics is marked Push to Exit / Emergency Release.

The Camden CM-400 button is 1-5/8 inch (40mm) in diameter. If you want a larger target, the SDC 440 Series is a large mushroom button emergency exit switch with a 2-5/8 inch diameter heavy duty design, and the SDC 420 Series uses 2 inch buttons and is described as code compliant. Those are the ones to quote when the drawing calls out an oversized emergency release head.

Check the legend before you swap. The Camden CM-400 covered here carries PUSH TO LOCK text in black on the faceplate, which is used to secure an opening on demand. The SDC 410, 420 and 440 Series are exit switches - the 440 is specifically a large mushroom button emergency exit switch. Electrically a momentary dry contact button is a momentary dry contact button, but a plate labeled for exit or emergency release in place of a lock button will mislead occupants and may not satisfy an inspector.

It stops someone jamming or twisting the button to defeat it. The 1-5/8 inch (40mm) mushroom head spins freely in the plate, so torque applied to the cap doesn't transfer to the switch stem or the mounting. Combined with the 18 gauge stainless faceplate, it is built for corridors, lobbies, and other public-side locations where a plastic button gets abused.

The CM-400 Series mushroom button comes in red, blue, or green, with other colors available on request. The 'PUSH TO LOCK' legend is printed in black text on the stainless plate, so the finish of the plate itself stays US32 / C32D stainless regardless of which button color you pick.

Hard wired. There is no wireless communication in the CM-400 mushroom button. It is a dry contact switch that you run low voltage cable from, back to your access control panel, relay, or power supply, switching up to 6 A at 30 VDC.

Both are built for abuse in different ways. The Camden CM-400 protects against vandalism with a free-spinning button and a heavy duty 18 gauge stainless steel faceplate. The SDC 430 Series is a heavy duty industrial mushroom button switch with a 1-1/2 inch round button, so it is the smaller head of the two. If the concern is people twisting or prying at the button in a public corridor, the free-spinning head on the CM-400 is the feature that addresses it; if the concern is industrial-duty switching, the 430 is the one specified for that use.

No, the CM-400 mushroom button is not illuminated. If you need a lit button so staff can find it in a dim corridor or see a status indication, the SDC 410 Series is an illuminated exit switch on a narrow frame mount, and the SDC 420 Series is an illuminated switch with 2 inch buttons.

Commercial. The CM-400 is an electronic access control device with an industrial grade 18 gauge stainless steel faceplate in US32 / C32D, built for the traffic you get in office buildings, schools, and healthcare corridors rather than a home install.