Max No. Of Wires Allowed Per Code For A 4" x 2" Elect. Switch/Gang Box ?

[Ken]

Depends on how many cubic inches the box is, the boxes come in different depths. Cubic inch capacity should be stamped on the box by the manufacturer.

Here is how you figure the size of the box you need:

Ken

[Ken]

Gee, I just noticed that I gave the exact same answer that was given in another post for basically the same question.

Ken

[Robert11]

Hello:

Relative to the standard 4 inch x 2 inch electrical gang (switch) box that is sized to hold one room on-off wall switch nicely, have the following question:

Per the Code, what is the maximum number of wires allowed inside ?

Or, is it (also) based on the maximum number of wire nuts allowed ?

Or,... ?

Would like to use it correctly; not much room in it for anything.

Thanks, B.

[Robert11]

Hi Ken,

Just a quick thanks.

Appreciate your help and opinion, as always.

Thanks, Bob

[John Grabowski]

Article 314 and table 314.16(A) address this issue.

A 4" square x 21/8"deep box is allowed to have 15- #14 wires or 13-#12 wires. Adding a device ring or surface cover will give you additional cubic inches thereby permitting additional conductors. You must deduct 2 conductors for each wiring device (Switch or receptacle). Pigtails don't count. Grounding conductor wires count as one. Cable clamps inside the box count as one. Conductors must be long enough to extend a minimum of 3" outside of the box (300.14).

A 4" x 21/8" x 21/8" deep is permitted to have 7 #14's and 6 #12's. Same rules apply.

John Grabowski