Good evening all!
I am tired of tripping my lone garage 15A circuit and running an extension cord into my mudroom, so I have decided to put a sub panel in the attached garage. I went today and got my permit, and I'm just trying to iron out a few details that are confusing me. I was a submarine electrician in the navy for 15'sh years so I have a pretty good grasp of electrical theory, checking equipment de-energized, working around live circuits, and making safe electrical connections. However, I'm still a newbie when it comes to code requirements, and I want to make sure it's safe for the wife and kids. (even though most of it seems to be common sense) I've tried calling the local inspector a few times, but I can't seem to catch him in the office.
The goal:
50A sub panel that is approx 75 feet from the 200A Main service equipment. New construction home, everything is less than 2 years old. I chose 50A because I already have the breaker and it keeps the cost of the feeder cable down, and I typically only run 1 piece of equipment and my dust collection at once.
The plan:
Install a 50A dual pole CB, run cable through the joist in the basement through the garage wall into a junction box where I will use conduit to enter the bottom of the Sub panel.
The question:
I understand the ground bar can't be bonded to the neutral in the sub panel. I know I need #6 copper or #4 Aluminum to run the feeder cable. My main silly question is: Does the equipment ground wire need to be insulated? I see lots of 6/3 NM-B out there, but I haven't seen 6/4. So i'm assuming I can use 6/3 NM with a ground to have my two hot conductors, neutral and the included ground wire. I'd like to use NM or other cable to be able to take advantage of the pre-engineered knockouts in my floor joist and not have to deal with conduit in the basement.
Operating an un-grounded system my entire career, I never had to worry about it other than grounding equipment chassis to the hull of the ship .
Thanks in advance!
Phil