When it comes to multi-family buildings, whether constructing a new structure or renovating an old one, some units must be made accessible for people with hearing and/or visual disabilities. These HVI communication units have extra features that electricians need to be aware of.
Two features that communication units have, not included in adaptable (non-ADA) units are visual fire alarm notification devices and visual doorbells.
In this post I will go over the visual doorbell, you’ll see they are not much different from non-visual doorbells.
Let’s start with the transformer, the HVI doorbell uses 24V, we need a location to install one. Fortunately, there are a few locations with framed ceilings in the units of the building I am presently working on. I was able to utilize one of these locations to install a transformer in the knockout of a four square box.
From the secondary side of this transformer I installed a two conductor cable to the doorbell button location at the front door, and to the first bedroom. From the first bedroom I installed another two conductor cable to the second bedroom.
The objective of the visual doorbell is to alert a hearing impaired resident that he has a visitor at the front door.
When a visitor presses the front door doorbell button an annoying audible sound and flashing light alerts the resident.
Electrician’s must also include a means of disabling the HVI doorbell so the resident can be undisturbed if he chooses. This is just an SPST toggle switch installed below the HVI device.
Here are two wiring methods for HVI doorbells.
I prefer method #2 because there are less wires at the button.
Hope this helps you the next time you’re installing an HVI doorbell.
Buddy, your San Francisco Electrician