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
863k 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 ...
21
votes
5answers
2k views

subpanel breaker tripped as well as main breaker - should I be concerned?

All... My garage had only one outlet so I extended it using surface raceways. Like a dummy, I did not turn off the breaker when I started the installation of the raceway. "I know what I'm doing ...
17
votes
5answers
8k views

What type of cable should I bury for a small utility shed?

I'm putting a 8x16 utility shed in my back yard. It will be 100 ft from the service panel. I want to run the supply line under ground. There will be one 4ft fluorescent light and two 120V receptacles....
16
votes
2answers
5k views

Considering doing a 100A sub panel install on my own. Any guidance would be much appreciated

My background: I am an Electrical Engineer by schooling and I'm a pretty handy guy overall. I have been working on and around just about everything since as long as I can remember. I have a good grasp ...
15
votes
4answers
9k views

GFI outlets tripped after power outage

I live in a rural area that has frequent power outages (Several per month. Less than a minute in duration). When the power is restored, several GFI outlets always trip. I am trying to track down ...
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 ...
13
votes
3answers
209k 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 ...
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 ...
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 ...
10
votes
3answers
2k views

Are the grounds and neutrals in this electrical subpanel reversed?

I would appreciate your feed back to help me understand the logic behind Bonding the Neutral and Isolating Ground as shown in the attached pics. Subject sub panel is dedicated to one of four ...
9
votes
3answers
1k views

Are there safety concerns or code violations with my garage sub-panel?

I recently bought a home and the garage has this sub panel that looks questionable to me. The garage has a circuit for 240v, and two other circuits that consists of two 120v wall outlets, and two 120v ...
9
votes
4answers
2k views

Can I run 275ft underground cable to pole barn?

I have a new 1500 sqft pole barn that needs electric. I expect to need 100Amp service at the barn which will have a 220V 15A compressor and 220V 25A welder. The rest of the barn will be 110V ...
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 ...
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 ...
8
votes
6answers
61k views

Can I connect a 100A subpanel to a 100A main panel?

I currently have a 100amp main service box but it is all full and some are even doubled up.I'm wondering if i can hook up a 100amp subpanel off of it? If so what size wire to go with? It would be on ...
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 ...
8
votes
3answers
1k views

Sub panel neutral and ground not bonded so why continuity between them?

I have a 125A GE PowerMark Gold Load Center "subpanel" at my detached garage. Subpanel has 2 hots, one neutral with no "connected" ground between panels. The subpanel ground bus ...
8
votes
3answers
1k views

Federal Pacific 200a main panel problem with oversized 100a 2pole breaker

There is a 200a FPE breaker box (yes, I am aware of all the problems). It is not in the homeowners budget to replace at this time. He has 2 issues: His panel is full His electric furnace is an older ...
8
votes
2answers
65k views

Can I feed a sub-panel from a sub-panel?

here is what I have. On the corner of my house, I have the main breaker box. I also have a 2nd sub panel that was installed later on the other side of the house which has 240V ac running to it. This ...
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 ...
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
4answers
12k views

How to use a 100 amp sub panel for a 50 amp input

I'm building a shed I want to add power to. To get power I'm planning to use the power that is going to my hot tub (50 amp). The hot tub has a 50 amp breaker from the main to a 50 amp breaker box ...
7
votes
2answers
602 views

Sub panel install issue

I had a sub panel installed recently. The plan was that i will be installing my own breakers. The sub is running off of the main about 25 feet away in my garage. I understand that the ground and ...
7
votes
2answers
836 views

Was this installed to code and is it still to code?

In 1995 an electrician who was also a friend of the family helped me out by installing a sub panel in my garage. He tapped the feeder cable directly into the main lugs in the main box and ran them to ...
7
votes
3answers
9k views

Can I add a subpanel?

Let me start off with the facts: I have 125 amp service that is fed via overhead lines to a center fed panel. I am maxed out on breakers, as every 110v breaker is now a tandem breaker. When other ...
7
votes
4answers
6k views

How to add a gfci and surge protector to pool pump line?

I want to add a gfci and surge protector to the 240v circuit for my pool pump. The 12 guage power wires (red and black) and ground (green) run from the corner of yard directly to the main breaker ...
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
972 views

Garage upgrade from 20 AMP to 50 AMP

I bought a house recently and I have some experience with electrical but I am not fully sure what would be the best course of action since I've never had a detached garage where the cable would be ...
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 ...
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 ...
6
votes
2answers
4k views

Why does my subpanel have 4 wires feeding into the lugs?

Background: This is a sub-panel for my pool equipment (filter pump, cleaner pump, and pool light). The wires coming from the main panel come in through the bottom, and the wires going out the left ...
6
votes
2answers
6k views

Adding second Ground Bus to Square D Sub Panel - Grounded via wire or just the screws?

I have added a sub panel next to my main panel. It is fed from a 100A breaker using 3-3-3-5 CU Service wire. I removed the ground screw to isolate the Neutral and I installed the ground bus that ...
6
votes
2answers
2k views

What size cable do I need for a replacement sub-panel?

I'm doing a kitchen remodel and while tearing down the walls I found quite a mess of wires from a sub-panel that exists in a small closet off the kitchen. It was so bad that I decided it needs to be ...
5
votes
5answers
7k 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 ...
5
votes
3answers
447 views

Ground wire pass-through safety switch to sub panel?

I have an out-building 150+ feet from the main service panel with its own 240v 60 amp sub panel. It is powered via a four wire bundle going through underground conduit -- 2 x 120v feeders, 1 neutral, ...
5
votes
3answers
1k views

Will #2 copper THHN be sufficient cable to run to the subpanel?

I have a 200 Amp Main panel. I have an outbuilding 150 ft away in which I need to install a sub-panel. I proposed to install a 200 amp sub-panel so if sometime in the future we choose to get a ...
5
votes
3answers
10k views

What is wrong with this panel wiring?

I have a main breaker panel downstairs, and a subpanel upstairs. After I hired an electrician to rerun the service entry cables, nothing upstairs is right, and all the upstairs lights blew as soon as ...
5
votes
2answers
612 views

Replacing subpanel that was fed with 3 wires

A contractor replaced my subpanel with a new one, and will come back for other work and inspection. (Old subpanel is Federal Pacific.) My home is in California, built in early 1980s. The subpanel is ...
5
votes
1answer
452 views

Ground wires absent from circuits exiting apartment panel

I'm taking a look at the (only) panel in my apartment (7 apartments in building, NYC) and I'm noticing that out of all the circuits leaving the panel, not a single one of them contains a ground wire. ...
5
votes
2answers
5k views

Does the neutral wire float or go to the neutral bus on a sub panel?

Does the neutral wire float or go to the neutral bus on a sub panel?
5
votes
2answers
859 views

Garage subpanel wiring

I recently bought a house that has a subpanel in the garage served by a 50 amp circuit from the main breaker. The breaker has 4 wires coming in: red, black, green, white. Currently, the subpanel ...
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 ...
5
votes
1answer
140 views

Is a grounded/neutral wire (not grounding wire) required to be run to a subpanel that will supply only 240V (2-pole) devices?

I'm installing a subpanel that will supply only 240V 2-pole devices. I'm positive I never will need the capability to run 120V (1-pole) devices. Am I required to run a neutral wire to the subpanel? ...
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 ...
4
votes
2answers
3k views

What are my options for running cable from surface-mount sub-panel in garage?

I'm building a new garage, mostly on my own. I hired an electrician to run cable and install a sub-panel, which was completed yesterday. Today it passed inspection. Next step is running cable for ...
4
votes
4answers
2k views

Wiring up a subpanel in attached workshop

I need to wire up my attached workshop, which is about 50' from the main panel. I don't want to make a bunch of homeruns and would rather install a workshop-specific panel for this task. I will be ...
4
votes
1answer
5k views

How can I add 100 amp electrical service to a shop?

I am going to wire my shop and want ot run #2 copper to a 100amp breaker panel. I really do not have the space in the 200 amp panel in the house, my question - is there a way to pull this wire off the ...
4
votes
2answers
1k views

Options for installing sub-panel

we are thinking about the best way to rewire our kitchen. It had 2 circuits when we moved in. We managed to add 2 circuits using an existing 3/4'' conduit that goes from the basement to our third ...
4
votes
2answers
3k views

Wiring of a metal detached garage?

I am looking to add power to my detached metal (enclosed carport) garage. With that said I am trying to figure out the most economical solution to wiring the garage. I would like to run the wire like ...
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 ...

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