Sub Panel hook up Question??

If you want some EFI/RMI protection on the feeder to the sub panel,use type AC cable.The conductors are twisted and protected by a metal or aluminum covering.The aluminum covering is much lighter than the metal.You can get this AC cable up to #2AWG.They also make a version of it with 2 grounding conductors,if you need isolated grounds.When putting any type of cable (romex,cords,) in any type of conduit,instead of individual conductors (THHN THWN) you will need conduit about 3 to 4 times larger than required for individual conductors.Its because of heat.You need lots of air space around cables because a cable is already tightly covered with a jacket.This is a example of it.Size of conduit for 3 #10 copper conductors,half inch.Size of coduit for 10/2 romex,2 inches

There are some rules you have to follow when selecting a place to mount a panelboard.If the closet you intend to install the panel in is a clothes closet or will ever be used as a clothes closet,you will have to choose another location.A clothes closet is considered a class III division II hazardous location because of easily ignitible fibers.A closet is the only place in a home where you can not install a panel.You also have to provide illumination for the workspace in front of then panel.The workspace depth has to be 3 feet,meaning you need at least 3 feet in front of the panel to work on it.The width must be 30 inches, and the height must be 78 inches.The entrance to the work space must be 24 inches wide and 78 inches tall.The circuit breakers can not be more than 78 inches from the floor.A panel can not be mounted to a combustable material.You can mount a panel to wood if you paint the wood with special fireproof paint.

I'd keeo the BP panel close to the devices it serves. If that puts it far away from your main panel, just use something like 8AWG between them. And even if you use Romex instead of pulling separate wires, it's nice to run it in steel flex conduit to protect it from RFI/EMI.

Another trick just suggested to me (and which seems to actually do something!!) is to attach a small sheet (say 5" x 11") of Stillpoints' ERS to the back of your fuse/breaker panel door and also the sub panel door. Really traps RFI.