BrightRhino
New member
- Location
- Glastonbury, CT
Hi,
I am setting up a small prototyping workshop in my garage, which currently seems to have three outlets, all on a single circuit shared with the outside lights. I want to add a 100 amp sub panel fed from the main breaker panel in the basement on the other end of the house. I just ran a piece of cat5 cable to measure the length of the pull, it's 75 feet between the two locations. The feeder cable will be under the joists in the unfinished part of the basement where the main breaker panel is, then be above suspended ceiling where the remaining 2/3 of the basement is finished. I called the local inspector, who is an electrician, and asked which cable would be correct, he said go to Home Depot and ask for the 100 amp cable. Home Depot in my area, CT, no longer carries SER cable in store, but I assume he means southwire 2-2-2-4 Aluminum. Looking at the 2017 NEC, which we follow here, it looks like that cable, used between an Eaton BR 100 amp breaker, which is rated at 75C and a Square D sub panel, which is also rated at 75C is only rated for 90 amps. Is that correct?
I just purchased a Bridgeport type CNC Mill, which I think requires a 20 amp 220V circuit, I'm waiting to hear back from the manufacturer. I also want a 50A 220V outlet for a welder, and another 20A 220V outlet for a surface grinder, along with a few 20A circuits for saws, vacuum, etc. It will only be me working in there, so rarely will there be more than one tool operating at once. I also want capacity for an electric vehicle charger later if we buy one.
I want plenty of spaces in the sub panel, so I am looking at a Square D 42 space QO panel with a 200 amp main breaker, which I would be using only as a local disconnect. Model QO142M200PC. I recently ran a sub panel for the basement workshop in the unfinished area where the main breaker panel is, which had only a single outlet used to run the sprinkler system. I added a 60 amp main lug panel with 3/4 emt for all the surface mounted boxes on the concrete walls, and a 20A 220V outlet for a metal lathe. The main panel, which is a Challenger 200A will be pretty full, and there are no more large holes in the ground/neutral bar for the garage SER feeder cable ground and neutral wires. How do I add additional ground/neutral spaces in that panel? Can I just buy a ground bar, screw it to the case and run a large copper wire connecting the old and new ground? I would have to move at least one large cable to the second ground bar first.
To recap:
Thanks, I have already learned so much from the discussions here.
Alex
I am setting up a small prototyping workshop in my garage, which currently seems to have three outlets, all on a single circuit shared with the outside lights. I want to add a 100 amp sub panel fed from the main breaker panel in the basement on the other end of the house. I just ran a piece of cat5 cable to measure the length of the pull, it's 75 feet between the two locations. The feeder cable will be under the joists in the unfinished part of the basement where the main breaker panel is, then be above suspended ceiling where the remaining 2/3 of the basement is finished. I called the local inspector, who is an electrician, and asked which cable would be correct, he said go to Home Depot and ask for the 100 amp cable. Home Depot in my area, CT, no longer carries SER cable in store, but I assume he means southwire 2-2-2-4 Aluminum. Looking at the 2017 NEC, which we follow here, it looks like that cable, used between an Eaton BR 100 amp breaker, which is rated at 75C and a Square D sub panel, which is also rated at 75C is only rated for 90 amps. Is that correct?
I just purchased a Bridgeport type CNC Mill, which I think requires a 20 amp 220V circuit, I'm waiting to hear back from the manufacturer. I also want a 50A 220V outlet for a welder, and another 20A 220V outlet for a surface grinder, along with a few 20A circuits for saws, vacuum, etc. It will only be me working in there, so rarely will there be more than one tool operating at once. I also want capacity for an electric vehicle charger later if we buy one.
I want plenty of spaces in the sub panel, so I am looking at a Square D 42 space QO panel with a 200 amp main breaker, which I would be using only as a local disconnect. Model QO142M200PC. I recently ran a sub panel for the basement workshop in the unfinished area where the main breaker panel is, which had only a single outlet used to run the sprinkler system. I added a 60 amp main lug panel with 3/4 emt for all the surface mounted boxes on the concrete walls, and a 20A 220V outlet for a metal lathe. The main panel, which is a Challenger 200A will be pretty full, and there are no more large holes in the ground/neutral bar for the garage SER feeder cable ground and neutral wires. How do I add additional ground/neutral spaces in that panel? Can I just buy a ground bar, screw it to the case and run a large copper wire connecting the old and new ground? I would have to move at least one large cable to the second ground bar first.
To recap:
- Is 2-2-2-4 SER All rated for 100A or 90A in my application?
- Can I use the 200A breaker in the sub panel just as a local disconnect protected by the 100A breaker in the main panel?
- How do I add more grounding/neutral space in the main panel (a Challenger 200A from 1986 when the house was built.)?
Thanks, I have already learned so much from the discussions here.
Alex
