Electrical boxes -- screw size?

[Percival P. Cassidy]

I have mislaid the screws that originally held one of those old ceramic light sockets in place on a hard plastic ("Bakelite"? Or is that a British name?) box.

What size and thread are those screws?

Perce

[RBM]

Not sure what your asking for, but there are ceramic lampholders that screw to 3 and 4 inch round boxes, which use 8/32 machine screws

[Nate Nagel]

Octagon (ceiling) box screws are 8-32. Wall box screws are 6-32. Fan support box screws and ground connection screws are 10-32.

Both ceiling and wall box screws are typically about 1-1/4" long, combo head. But if you're like me and you use the old antique pressed brass switch/receptacle cover plates, you'll need to buy a pack of 6-32 *flat* head screws to hold in your switches and receps.

Oddly enough I was just in the Orange Colored Store last night because I'd used the last of my stash of ceiling box screws, and they *didn't sell them.* When I asked the electrical guy, he said "huh, that's a good idea, wonder why we don't carry those." I bet Dominion sells 'em but I won't be able to get over there until next Saturday.

nate

[Percival P. Cassidy]

8-32 was my guess, but it just pushed through the first hole. Worked fine in the second hole, so I used a sheet-metal screw in the first hole, which I assume had a stripped thread.

Perce

[Tyler]

replying to Percival P. Cassidy, Tyler wrote: I?m so confused by this and have never gotten to the bottom of it. I have run into needing a longer screw than included with ceiling boxes/junction boxes.

6-32 is too small (threads in but is wiggly) and 8-32 is too large. I have found in my miscellaneous screws some sort of perfect in between size that I?m wondering if is a metric. Anytime I look into it, people just say 6-32 for wall stuff and 8-32 for ceiling stuff and that?s that. But this simply isn?t the case in my experience. There is a metric that must be similar to what a 7-32 screw would be.

[gfretwell]

Standard device boxes use 6-32, ceiling boxes (octagons) intended for luminaires use 8-32 and fan boxes use 10-32. There are no metric screws in current US boxes. Some day maybe and if you are in Canada, who knows?

[rbowman]

My guess is RaCo or whoever makes boxes these days is using taps that should have been replaced sometime last year.

[gfretwell]

There are also speed nuts and even T nuts that will clip over the ears of a box but usually you can just thread it to the next bigger size. That is why Klein sells that screwdriver style tap that starts 6-32 and ends up 10-32. Keep screwing it in until it bites ;-)

[Churchx]

Same problem...6-32 too small, 8-32 too big. I found a pair that did fit in my "variety" jar. Not 6, not 8.....right here in Pennsylvania.....box installed in 1995.

[Mark]

My octagon ceiling fan box has a label that says to use 8-24 3/4 screws.

[Clare Snyder]

The 2 common sizes are 6-32 and 8-32 - the screws that attach devices like switches or fuplex recepticles are commonly 6-32. SOME ground screws and cable retainer screws are 10-24 (here in Canada where those screws are most often Roberson (aka squarehead) screws)

[TimR]

And down here some will be ECX, that weird hybrid nobody has a screwdriver for.

I just looked at a few random boxes around my house and shed and almost all were straight slot, though.