wiring above a new ceiling

I'm in the process of renovating the top floor of a 100 year old row house. The house has roof with a very slight slope and I framed up a new flat ceiling with 2x4's that are just below the existing roof joists. I'm getting ready to start my electrical rough-in and was curious about running wire (Romex NM-B) in this "attic" space. Should I be drilling holes through all the ceiling joists to run the wire, or can I just lay it loose over top of the new ceiling joists? If I can lay it loose, should I be securing the wire to the joists periodically with staples? My wiring books don't seem to cover this kind of condition.

Thanks.

 

2 X 4 ceiling joist? Sure hope your going to add some bracing to the rafters.

 

I would run it across the 2x4s and staple it to every other one. That's code compliant or better.

Is Wiring Simplified part of your collection?

On a different but related question, how long are the 2x4s?

 

Joe, every house I lived in had 2X4 ceiling joists. He didn't mention the rafter size or if it is a gable roof but if it is the ceiling joists don't support the rafters. At most they act as ties to keep the walls from spreading. Roof weight is vectored on the walls. Of course his ceiling joists only support the new ceiling anyway.

So long as the cables are protected that is fine as long as they are stapled.

 

I didn't realize the ceiling framing would be so controversial. The max span is 12'-6". In the middle of the span there is a another 2x4 fastened to the top of the ceiling joists running perpendicular to the span. That cross member is braced to the roof joists above. It's pretty typical construction here in Philadelphia.

Nashkat1, thanks for the heads up on "Wiring Simplified." I don't have that one.