Electrical – How to make the electrical box dustproof


I have a 1-gang box that I'm installing a switch in, for my wood shop. I need to make it dust-resistant, if not absolutely dustproof. I can't use a waterproof box because I don't think they're made for the depth I need (3.5") to fit the switch. Do they sell covers for the screw holes of j boxes, like they sell knockout covers? If so, what are these things called? If not, what are some other possible approaches?

Best Answer

Use a weatherproof box and a weatherproof extension ring (or rings if you need a lot of depth) if you cannot find a weatherproof box to suit.

Or, just seal up the box with duct seal (non-hardening electrical putty for sealing up conduits.)

Unless you use a weatherproof switch enclosure (which may not be compatible with whatever absurdly deep switch you have chosen if it's not like a normal toggle switch at the mounting end) the switch itself will be an entry for dust into exactly the places you most don't want it.

Depending on the nature/purpose of the switch, enclosing the entire switch behind a gasketed door might be appropriate - but not if it's something that requires immediate access, like an emergency stop (though most of those are dust-resistant and/or waterproof, or available that way, anyhow.)

Addressing dust collection/control is another approach. It's not good to breathe that stuff, so getting it out of the air ASAP is good for you AND your electrical items.