new sub panel

BlueBSH

Alright, went out last night and bought a GE load center 125 amp main lug to use as a sub panel, its abou 12" x 12" in size, its going to be installed right next to my existing panel as an extension to it since im out of circuits... question is, this panel will be for the basement only, the highest breaker I could find for my main panel is 50 amp that is 1" in height, will this be enough for a basement install? there will be no high wattage devices on the lines, just three lighting runs with a max 20 amp breaker on them, and three outlet runs each on 20 amp breakers, no dryers / washers / stoves... no supplemental heat... now there is 2" high breakers at 80amp that is model THQL2180P, and my main ge panel says it supports THQL breakers... but would 80 Amps be overkill for a sub panel?

next question is with 50 Amp I assume I'd use 6 gauge stranded wire (SER), but what would 80 amps require?

I know I can not bond neutral in the sub panel, so it's isolated right now, I have a seperate ground bar. so I just run that ground bar to the main panel ground or does it need to be its own isolated grounding system? I'd assume since its so close it could just connect to the main ground? So at this point I'd need a minimum 4 pair Red/Black/White/Ground 6 gauge wire to run from the main box back to the sub panel a whole 1 ft away...

is there any requirements how you run the line from the main panel to the sub panel? my main panel seems to only have knockouts big enough for 6 gage wire on the top and sides not the bottom, my sub panel has them on the top bottom and right side, nothing on the left side I wanted to place it either right below the main panel or to the right of it, I don't have too much room to work with here... are there any clearance requirements on placing the panel?

Also what screws would yo use to securely mount this to OSB? I have what seems like 3/4" OSB on the basement wall where the main panel is, not sure what would be the best to hold this 1ftx1ft sub panel up, it only has three screw holes in it...

and finally the last question, conduit or no conduit to the main panel? if so what to use? I don't have tools to bend metal conduit and its only 1ft away from the main panel

Scuba_Dave

What size is your service feed ?
I have a 200a service & put a 100a sub right next to the 200a panel
Plenty of room for breakers that way

BlueBSH

Main service panel is 200 amp, wish I could just replace the existing panel with a longer one but it came to be too much money to rewire the entire panel

Scuba_Dave

If your main panel is a 200a - & out of spaces I'd install a 100a sub
That way you have plenty of room for any future circuits

macdonald

What kind of panel do you currently have. Is there tandem breakers you can install to free up some room

BlueBSH

right now I have a 200 amp GE Powermark load center with 34 1/2" breaker slots... all but 1 slot is used and to use AFIC as required now I have no room, so a new set of slots... and I do not know of any tandem AFCI breakers, nor does anyone around me sell tandom breakers for GE panels

jimmy21

50 amp would be plenty for what your talking about, but you should be able to do a higher amperage install for nearly the same cost if the panels are that close. Im sure you could order an 80 or 100 amp breaker online for the same price as the 50 amp locally

Jim Port

Breaker prices jump considerably after the 60 amp size.

__________________
Answers based on the National Electrical Code. Local amendments may apply. Check with your local building officials.

Scuba_Dave

Yeah but not too bad...50a ~$16...80a $32.....100a $48-56

Stubbie

The 50 amp breaker you have is two THQP's handle tied together correct? That would be two of the 1/2" breakers tied together.

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Stubbie

Amazingglazier

Just bought a 100 Amp thql breaker for my GE Powermark Main Panel at Lowes for 39 bucks, so they are available.

curiousB

I think you can use 8 AWG for 50A circuit. Bigger is fine but not needed.

I just did what you are doing. I mounted a sub panel next to main. I didn't run a ground wire at all. Instead I used a rigid conduit nipple 1 1/4" by 6" long and used jam nuts on either side of metal walls (4 nuts in total). I was under the impression this is enough to bond the grounds together across the two panels.

I was able to use an existing 3/4" cutout and make it big enough for the 1 1/4" conduit by using a hole punch (Greenlee style). This allowed me a good location on the sub to bring the wires in and then lined up nicely with a 1 1/4 punchout on the main panel. Be sure to use nylon bushings on inside threads of the conduit connectors.