Hi. I would like to put in a stairway between a utility room in my house and the space above my garage which is adjacent to the utility room but 4 feet higher as it is a split level house design. The new doorway will have 10 romex wires running across the middle of the doorway.
I would like to splice these wires with junction boxes to run around the door frame.
How many wires (12/2) can I put in each junction box? What size box should I use? Is blue plastic okay? These boxes will be accessible in the attic space.
Thank you all very much for your input.
That depends on how big the junction box is. Are all of the conductors #12? You have to allow 2.25 cu in for each #12 and 2.00 cu in for each #14. Plastic is fine. A lot of the plastic boxes have the cu in size stamped on them. I would get a large junction box with room for expansion.