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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25
votes
3answers
861k 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 ...
13
votes
1answer
176k 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 ...
12
votes
4answers
147k 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
4k 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 ...
2
votes
4answers
34k 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 ...
4
votes
6answers
40k 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
105k 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 ...
13
votes
3answers
208k 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
160k 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
61k 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 ...
3
votes
2answers
75k views

100 AMP garage sub-panel from 200 AMP house

I've checked a number of the other questions but not finding the specific answer I need. I'm wiring a 100 AMP garage sub-panel from a 200 AMP main in my house. I plan to install a 100 AMP circuit ...
1
vote
1answer
11k 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 ...
9
votes
3answers
2k views

Running electrical to a shed

I have a shed in my backyard about 200ft from the house. I would like to run electrical to the shed to install 2 or 3 power outlets, and two LED lights for the inside. Currently from the house to ...
4
votes
3answers
61k 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 ...
3
votes
1answer
1k 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. ...
3
votes
4answers
13k 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 ...
3
votes
2answers
127 views

8 AWG solid EGC in raceway for 100 amp subpanel

I'm adding a 100 amp subpanel to my detached garage and have a question about the EGC I've already pulled through the underground LFNC-B raceway. Taking the advice from a similar post on this forum, I ...
3
votes
3answers
1k views

How can I connect 2AWG cable to my 100A panel?

I have bought a gazebo (closed) that will serve as a studio and I want to place it on the edge of a wood that is approximately 400 feet from my house. I was planning to run underground wiring from my ...
2
votes
3answers
464 views

20A & 30A dual feed into subpanel

Okay so this is my first shot at this question, but not my first time trying to research the subject. I am in the process of designing a tiny house and have started thinking electrical. NOTE : I will ...
2
votes
3answers
3k 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 ...
1
vote
2answers
2k 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 ...
1
vote
2answers
581 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, ...
11
votes
4answers
6k 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 ...
7
votes
1answer
27k views

200 amp service entrance to 200 amp sub panel?

I have a 200 amp service entrance outdoor breaker box. I want to install an indoor breaker box with 200 amp service about 5' away so I can access breakers from inside the house. The actual wire run ...
6
votes
3answers
1k views

Adding critical-loads sub-panel with a PV install, rationale and ampacity calculation

I'm considering adding a critical-loads subpanel near my main load center, in conjunction with a small grid-tie solar system, and with connection for backup power. Please critique my rationale for ...
4
votes
2answers
6k views

Subpanel has neutral and ground bonded in detached structure - should I isolate?

I have a detached garage built in 1979 with a Cutler Hammer subpanel with a 3-wire 8AWG feeder (hot/hot/neutral) on 40A breaker from the main house panel. Subpanel has a dedicated ground rod ...
4
votes
3answers
40k 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 ...
8
votes
3answers
22k 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 ...
6
votes
3answers
13k 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
6k 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 ...
4
votes
2answers
6k 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 (...
3
votes
1answer
320 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
1answer
2k views

Can I add a sub-panel near the main disconnect outside my house?

I have an outside main disconnect of 125 amp and a inside main panel. The disconnect panel outside has an extra space that will accept a dual pole breaker. What I would like to do is add a sub-panel ...
3
votes
4answers
12k 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
3k 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
2answers
358 views

Is 50 amp subpanel allowed in Seattle area?

I am in Seattle area and planning to add a subpanel right next to main panel in garage. For my purposes, a 50 amp subpanel work would fine. As my main panel is completely full, I would either need to ...
2
votes
4answers
8k 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
1k views

Add circuit off main disconnect or sub-panel required?

I have an outside main disconnect of 200 amp and a inside main panel in the garage. The disconnect panel outside also has 8 or 10 breaker slots in it: four are occupied by double breakers for sub-...
2
votes
1answer
191 views

Separating neutral and ground in panel

I have a 200 amp combination disconnect and 10 circuit panel on the pole feeding my 200 amp panel in my house. Is the panel on my pole considered my main panel and the one in my house a sub-panel ...
2
votes
1answer
3k views

Electrical panel ground issue

I just moved my shop to a new location here in sunny North Hollywood CA and was looking over the electrical panel and noticed there is no ground wire coming in from the service entrance. There is a ...
2
votes
1answer
953 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 ...
1
vote
2answers
1k views

Wiring a sub-panel with an equal sized breaker on each end of the feed, which will trip first?

I'm wiring up a small backyard tiny house for use as a rental.  Main power will be supplied by a 30A breaker and 10/2 wire coming from the main house, to an RV box, then to an RV plug, then into the ...
1
vote
1answer
494 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
3answers
1k views

Installing a sub panel to a GE split bus panel

I want to install a sub panel to my GE split bus panel. The diagram indicates that I could replace the two full sized 2-pole breakers (2 inch wide each) on the upper left with three compact 2-pole ...
1
vote
1answer
3k 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
12k 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). ...
0
votes
2answers
1k 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
3answers
2k views

Electrical Circuit for Detached Shed 200 ft

Would it be acceptable to run a branch circuit from a panel to a detached storage shed that will be approximately 200 feet away, instead of a feeder with sub-panel and grounding rods? The circuit ...
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 ...