Feeding 100 Amp. Subpanel

[faterikcartman]

I want to feed a 100 Amp subpanel from a 100 Amp fuse in my 200 Amp main service panel. Just to let you know, I am having a licensed electrician make the connections but to save money I am doing all the grunt work (which I totally regret but now I'm committed and determined).

My question pertains solely to feeding the 100 Amp sub and the correct, per 2002 NEC, requirements.

Ideally, I would like to feed it (through a single stud from the main right next to it in my attached garage) with 2/3 copper NM-B (3 conductor plus ground, 2 AWG Romex) but from consulting various charts am concerned that that would not be big enough due to necessary derating because it is Romex.

My alternatives (as I see them now) are using 1/0 SER but that would be aluminum which I rather not use, or running 1 AWG THHN in 1 1/2" conduit but since I'm not cutting a 1 1/2" hole in my 2x4 stud that would mean a funky short run of conduit exposed in my garage which I do not want.

Is 2/3 Romex up to 2002 code or do I need to go larger (SER since there is no Romex larger than 2/3)?

Thanks in advance.

[HayZee518]

2/3 copper is perfectly legal and don't worry about the derating factors. Being it's such a short distance away it doesn't even enter into the calculation. The four wires are part of a cable assembly so derating isn't necessary.
In your sub panel don't tie the neutral to the enclosure ground with the screw or jumper. Install an auxillary ground bar and tie the bare copper from the 2/3 cable to this bus. Scrape the paint away from where the two screws connect the bar to the case. The red and black go to the main lugs in your sub and the white goes to the neutral strip. For branch circuits all bare grounds go to the aux bar, all whites to the neutral.