Questions tagged [subpanel]

For questions about an [electrical-panel] that is fed from another [electrical-panel] instead of being fed directly by a utility service or separately derived service (such as a generator or inverter).

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21
votes
3answers
601k views

What wire gauge do I need for a 100 Amp subpanel at the end of a 60' wire run?

I am adding an attached garage to my house. I'm going to be putting in a 100 Amp subpanel which is about 60 feet away and run through the basement joists. What gauge wire do you recommend for ...
11
votes
1answer
150k views

What size wire should I use to feed a subpanel in my garage?

My main panel has been upgraded to 100 amps. I would like to add a subpanel in the garage which would supply: 20 amp Mig welder running on 120 volts, but later upgrade to a larger Mig welder as i ...
9
votes
4answers
115k views

How to properly ground a subpanel in detached building?

I Will be installing a subpanel in a detached garage. The subpanel will be 60 amp. The garage is about 30' from the main-panel in-house, and I will of course get an exact length before selecting the ...
5
votes
1answer
2k views

Can I feed 2 sub-panels off one breaker?

I have a 225A main service panel. I also have 2 sub-panels with 125A and 200A ratings respectively. There's a 100A 2-pole breaker in my main panel. I want to feed both sub-panels from that single ...
5
votes
6answers
34k views

Can I install a Subpanel (in a seperate building) using a 3 wire connection (2 hots and 1 grounded neutral)?

Can I use a 3 wire connection (2 hots and 1 grounded neutral) to install a sub panel in a separate structure if I install a separate ground rod to the grounding bus in sub panel? I have 8/3 w/o ...
8
votes
2answers
77k views

Why does a subpanel need separate ground and neutral?

Why does a power sub panel have to have separate neutral and ground bars other than code satisfaction? Does a sub panel need a main breaker if there is one at the main? Also, does the sub panel ...
2
votes
4answers
22k views

How do I determine the fill rating of a conduit?

I Will be installing a subpanel in a detached garage. The subpanel will be 60 amp. The garage is about 30' from the main-panel in-house, and I will of course get an exact length before selecting the ...
12
votes
2answers
136k views

How do I properly ground my subpanel that only has one neutral/ground bar?

I am adding a sub panel in an unattached building. My sub panel has the connection for the 2 hot wires coming from the source panel (a 40 amp double breaker) In addition it has one neutral/ground bar ...
2
votes
2answers
104k views

What size wire should I use for a 60amp subpanel?

I am installing a 60 amp subpanel in a workshop in my backyard and I will have 2 - 20 amp services with 4-5 outlets on each and 1 - 15 amp service for lighting. The length from the main panel to the ...
9
votes
2answers
51k views

How to determine the correct capacity for a sub-panel for a shop?

I plan to install a sub-panel for my woodworking shop, and would like to determine the total capacity that should supply that sub-panel. These are the main items that will likely be running in the ...
5
votes
5answers
5k views

I do not have power to all my breakers

I exchanged my double pole 40 ampere breaker that supplied my sub panel for my garage with a single pole 40 ampere and now out of my six breakers in the sub panel only 1,3, and 5 have power. How do I ...
3
votes
1answer
261 views

Can I do a 125A subpanel feeder with slightly-larger-than-#3 wire?

How they are all connected: With all the details and data given below. So Can I do a 125A subpanel feeder with slightly-larger-than-#3 wire? This is detail directly related to the post. Question. ...
1
vote
2answers
313 views

Cabin Wiring Plan Revisited

OK, So I’ve update my wiring plan … see images. I have more details now, such a part numbers, specifications and ratings, etc. I’ve consolidated much input from a couple of forums as well as Stack, ...
1
vote
1answer
1k views

Should neutral be bonded to ground in main and subpanels?

I had a licensed electrician replace my main panel and also install a subpanel in my garage. At the time I knew nothing about electrical, and now I know just barely more than nothing. I have ...
10
votes
4answers
5k views

Would running a new subpanel in parallel meet NEC requirements? If not, what should I do?

Background U.S.A. Voltages/power present. My house has a 125A Power Mains breaker at the street. A buried line runs from the street breaker to my main panel on exterior wall outside of house. The ...
8
votes
1answer
4k views

What wire and conduit is required for an attached-garage subpanel?

To make my garage more usable as a workshop, I'm planning to add a subpanel which can feed a number of additional outlets. 60 amps would be plenty for my current needs, but I'd like to go with 100 so ...
4
votes
3answers
35k views

What type of wire should I use to feed a 70 ampere subpanel?

Finishing a basement and I need to add a subpanel. Main panel is outside. Subpanel will be in the basement. 70 Amp breaker in the main to feed the subpanel. I was thinking THHN but would this mean ...
1
vote
1answer
10k views

How to determine what type and gauge of wire should used for underground wiring to a detached subpanel?

I Will be installing a subpanel in a detached garage. The subpanel will be 60 amp. The garage is about 30' from the main-panel in-house, and I will of course get an exact length before selecting the ...
8
votes
3answers
15k views

Can an electrical subpanel go underneath plumbing?

I was about to wire up my new basement subpanel when I realized I had put it directly under a toilet. I don't think this is a code violation. I can relocate it with some difficulty. I'm also ...
4
votes
3answers
8k views

What should I do if the AFCI breaker neutral pigtail is too short?

I am wiring a house that I built, and code says I need an AFCI for the bedroom circuit. The panel that I will be installing this AFCI breaker in is a subpanel, so my ground/neutrals are on 2 ...
4
votes
1answer
3k views

Arc-fault breaker in sub panel, pigtail to neutral bus or ground bus?

I recently replaced an arc-fault breaker in our subpanel that I thought to be faulty (it kept tripping at strange intervals around when I added a new dimmer, but I found no issues with my dimmer ...
3
votes
1answer
257 views

Grounding subpanels located ~100ft from main breaker

Based on this question on EGCs in conduit (in the context of branch circuits) and this question on conduit as a sole ground source, I would like to know whether two subpanels, located ~100ft from the ...
3
votes
4answers
9k views

How can I install an electrical panel when the stud cavity is too narrow?

I am installing a sub panel in my garage and ran into a problem. I have the usual 14" of space in the stud cavity but the problem is that the subpanel I bought is 14 1/4" wide. I'm wondering what ...
2
votes
1answer
1k views

Is it bad to have a circuit breaker on both ends of a feeder?

My main service panel only has a single breaker connected to a feeder wire which goes to my subpanel. I'd like a main disconnect closer to my subpanel so I don't have to go all the way to my main ...
2
votes
4answers
5k views

Space requirements for first subpanel and wiring preference

I would like to install two subpanels and my main panel is full of breakers. Would it be better to feed both subpanels directly from main or have 1st subpanel off main and 2nd subpanel off 1st ...
2
votes
1answer
662 views

Replacing subpanel in detached building - yet another ground/neutral question

Here's the situation. I've added on to my detached shop/garage and need to upgrade the very small subpanel. The existing garage pre-dates the 2008 NEC by at least a decade, and is supplied by a 3 ...
2
votes
4answers
4k views

Can I run a ground wire along the outside of conduit?

I have a sub panel on back of house. From main in garage is three wire. 2 hot one neutral. NO GROUND WIRE. Sub has a single bar used as neutral and grounds. Its bonded to case (Screw in). I will ...
2
votes
2answers
397 views

Can a sub-panel have a larger main breaker than the feeder breaker in the main panel?

I have a weird setup that I'm trying to configure, but I'm only 90% certain of my logic (and with electrical items I want to be 100%). I have a new 400A meter/main combo unit with 1 built-in (...
2
votes
2answers
18k views

Is it ok to use a ground rod at a subpanel instead of a fourth wire?

I understand running the neutral wire back to the main service panel and not bonding the subpanel... but running the equipment ground back to the main panel seems to get conflicting answers. If ...
1
vote
1answer
350 views

How can I replace an I-T-E panelboard? [closed]

I have an old 225 Amp 30 space commercial flush mount sub-panel in my home with bolt on breakers that has worked for years. Now, there's 120v on one bus and 0 volts on the other bus. When I remove ...
1
vote
1answer
2k views

How can I safely connect a subpanel in a detached garage to the main with a 3-wire connection?

This weekend I attempted to install a breaker box into a pre-wired garage. The previous owners took the breaker box with them when they moved, and since I have installed quite a few subpanels, it ...
1
vote
1answer
5k views

Can I use a 30A backfeed breaker when I'm not using the generator?

I have a panel in my garage with a "Generator" 30A breaker. I know I shouldn't be backfeeding the generator (I inherited this setup and am scheduling an electrician to put in a transfer switch). ...
1
vote
3answers
2k views

2 wire sub-panel corrective action

Can I correct 2 wire supply by adding a bare copper wire buried to sub-panels? I have two out-buildings with sub-panels fed by 6/2 wire w/ground. The main is 100 amp The sub-panels each has a 50 amp ...
0
votes
2answers
748 views

Should I bond neutral in sub panel- there is no electrical ground

I have a question about my sub panel that I'm installing in a shed in the back yard. I'm using a 3 wire feed from the main panel to the sub panel (H-H-N). ...because I'm using the 3 wire feed, I'm ...
0
votes
1answer
61 views

Main Load Center for subpanel

Can a main load center box with no main breaker be used as a sub panel in a detached garage. Was told to run a #2 copper since it was about 150 ft away from the house.
0
votes
1answer
73 views

What type and gauge ground wire do I need when using 1/0 hot and neutral wires

I have a 260 ft run from my main 225A panel to a 100A subpanel in a steel shop out in my yard. I have a #4 bare copper wire grounded to the rebar in the foundation of the shop. Not knowing what I ...
0
votes
3answers
536 views

Old Fuse Box Used As A Subpanel

Home built in the 50's has a fuse box that's currently being used as a subpanel in the garage. The garage is attached to the house by the means of a 8 foot wide enclosed breezeway/mudroom. My problem ...
0
votes
2answers
424 views

What is considered “servicing” for NEC 225.30?

I previously asked a question (Grounding subpanels located ~100ft from main breaker) where I was informed of NEC 225.30, which states that a building [...] shall be supplied by only one feeder or ...
0
votes
0answers
32 views

Separate ground/neutral bars in sub [duplicate]

OK..I have another sub-panel question. My sub has a 50 amp gfci that powers (old) spa. Currently this sub panel has a single neutral/ground bar. This bar is bonded, (screw is in), to the metal ...