snorky18
Well-known member
We just moved in a month ago. We’re out in the county in rural Alabama. The only permit required to build this house 5 years ago was septic. So no building inspectors, codes, etc. That being said, I’m planning on doing everything to NEC standards. The closest town is still under 2002 NEC, so that’s what I’m planning to use.
We currently have a 200 Amp service to the house. 40 space panel. It’s full, and one double tapped breaker (some will say it’s common, and it may be, but if it’s not a Square D breaker intended for that purpose, I don’t like it). The electrician who wired our house acted like wire was free, and taking the time to plan your circuits out was unnecessary. Whole house is #12NM or larger too; no 15 amp circuits.
I’m going to put a 100 Amp 20 Space subpanel in my garage. The hot water heater (located in the garage) will be powered from the 100 Amp Subpanel in the garage to allow space in the main panel for the new 100A breaker to feed the subpanel. I’m also going to relocate 1 circuit (the garage receptacles) to be powered from the subpanel rather than the main panel, and this will get rid of the double tap in the main. Right now the only other circuit I’m adding is for my 240 Volt 15 Amp Compressor. I wrote out a wish list of everything I think I even might ever imagine I would want to power off this subpanel, and came up with ~14 poles/spaces used total.
I’m well aware of the debate over using feeder tables for subpanels, etc. I’d rather just spend more time in the garage, less time arguing / worrying, a few extra $, and have the bigger wire anyway, so I sized using table 310.16, 60 degree column. So I decided on 1/0 SER (3 conductors with ground), which can be had locally for ~$1.50/foot. Planning on putting alumanox on all the exposed connections.
I’m going to route the SER down from the main panel into the “crawl” space (~7’ of headroom), over to the garage, and backup through the floor, into the stud bay where I’m going to install the panel.
Questions:
1) Does SER need conduit to protect it where it runs through 2x4 framing, such as where it comes up through the floor into the stud bay? Or is it just like running Romex, and the jacket alone is enough to protect it? If I do need conduit, what size should I put in, and what should I put on the top of the conduit where it enters the panel (insulating bushing?), and the bottom where the wire first enters the conduit? Sch 40 or 80? (I’ve never worked with conduit before, and would probably use PVC).
I ask because the SE cable that feeds our 200 amp service is secured to the underside of the joists, but when it penetrates through the floor up to the main panel in the laundry room, it’s encased in ~2” conduit.
2) My biggest question / problem is that our 200A main panel is fed from below, most of the branch circuits powered by the main panel are routed through the bottom of the panel, and there are no large knockouts available for the SER at the bottom of the panel. I know you can make your own under some circumstances, but I don’t know if that would be appropriate here, or if there is physically room for the hole and wire. I will be installing another subpanel for some basement revisions in the next few weeks, so I need to plan for routing two separate SER cables, each 1/0 - 3 conductor with ground. The top of the main panel has a lot more room for additional wires.
What size hole do I need to run either the conduit or the SER with wire clamp?
Do I need to run the SER up the empty stud bay next to the main panel, then horizontally through the stud, then come in from the top of the main panel?
Or make my own knockout at the bottom if there’s room?
Or drill through the studs and come in from the side? (not sure how big hole would have to be to accommodate wire clamp or conduit).
Sorry to be so wordy, and thanks for the help.
Bottom of panel:
Top of panel:
We currently have a 200 Amp service to the house. 40 space panel. It’s full, and one double tapped breaker (some will say it’s common, and it may be, but if it’s not a Square D breaker intended for that purpose, I don’t like it). The electrician who wired our house acted like wire was free, and taking the time to plan your circuits out was unnecessary. Whole house is #12NM or larger too; no 15 amp circuits.
I’m going to put a 100 Amp 20 Space subpanel in my garage. The hot water heater (located in the garage) will be powered from the 100 Amp Subpanel in the garage to allow space in the main panel for the new 100A breaker to feed the subpanel. I’m also going to relocate 1 circuit (the garage receptacles) to be powered from the subpanel rather than the main panel, and this will get rid of the double tap in the main. Right now the only other circuit I’m adding is for my 240 Volt 15 Amp Compressor. I wrote out a wish list of everything I think I even might ever imagine I would want to power off this subpanel, and came up with ~14 poles/spaces used total.
I’m well aware of the debate over using feeder tables for subpanels, etc. I’d rather just spend more time in the garage, less time arguing / worrying, a few extra $, and have the bigger wire anyway, so I sized using table 310.16, 60 degree column. So I decided on 1/0 SER (3 conductors with ground), which can be had locally for ~$1.50/foot. Planning on putting alumanox on all the exposed connections.
I’m going to route the SER down from the main panel into the “crawl” space (~7’ of headroom), over to the garage, and backup through the floor, into the stud bay where I’m going to install the panel.
Questions:
1) Does SER need conduit to protect it where it runs through 2x4 framing, such as where it comes up through the floor into the stud bay? Or is it just like running Romex, and the jacket alone is enough to protect it? If I do need conduit, what size should I put in, and what should I put on the top of the conduit where it enters the panel (insulating bushing?), and the bottom where the wire first enters the conduit? Sch 40 or 80? (I’ve never worked with conduit before, and would probably use PVC).
I ask because the SE cable that feeds our 200 amp service is secured to the underside of the joists, but when it penetrates through the floor up to the main panel in the laundry room, it’s encased in ~2” conduit.
2) My biggest question / problem is that our 200A main panel is fed from below, most of the branch circuits powered by the main panel are routed through the bottom of the panel, and there are no large knockouts available for the SER at the bottom of the panel. I know you can make your own under some circumstances, but I don’t know if that would be appropriate here, or if there is physically room for the hole and wire. I will be installing another subpanel for some basement revisions in the next few weeks, so I need to plan for routing two separate SER cables, each 1/0 - 3 conductor with ground. The top of the main panel has a lot more room for additional wires.
What size hole do I need to run either the conduit or the SER with wire clamp?
Do I need to run the SER up the empty stud bay next to the main panel, then horizontally through the stud, then come in from the top of the main panel?
Or make my own knockout at the bottom if there’s room?
Or drill through the studs and come in from the side? (not sure how big hole would have to be to accommodate wire clamp or conduit).
Sorry to be so wordy, and thanks for the help.
Bottom of panel:
Top of panel:
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