Make sure the box is flush with wood not inset. I think it is okay, but it may be a fire code issue and not a electrical one. Having said that I have also seen and installed many switches in wood.

 

The box needs to be flush or extend from a combustible surface.

 

Thanks for your input cjp. I live in an old house from 1888 and though it's mostly modernized, there are a couple outlets in old wooden walls in the kitchen. I still may insert a drywall panel in between the shelf sections to just to keep the new work through non-combustable material.

 

Hi Jim: I keep reading this that the box must be flush or extend from a combustible surface. I don't understand what this means being that I thought all electrical boxes are flush with the surface that they are attached to? And does extend mean sticking out of the wall?

 

Sometimes they end up inset in the wall. Eg; An outlet in a drywall wall has paneling put over it. Now the box is not flush.

The box needs to stick out the same amount as the wall covering.

 

Thanks.

 

Under the NEC, a box can be recessed up to 1/4" in a non combustible surface like drywall. In a combustible surface like wood it needs to be flush or proud of the surface to avoid exposing the combustible surface to an arc or spark.

 

Thanks. I understand and it makes sense.

 

Well, the shelves are going in and I've decided to actually insert a short panel of sheetrock between the shelf sections where the outlet will go. How much clearance would be advisable laterally to the outlet box for combustible material as that will be wood, unless I were to line even the insides of the space with sheetrock.

 

The gap outside the box can be no larger than 1/8".

 

I meant the space between the sides of the actual outlet box and combustible material. The vertical walls of the bookshelves will be on both sides of the box where it is hanging on the sheetrock face inserted between two sections of book shelves.