Running Subpanel into garage

[Alan Greene]

I am looking at running a sub-panel, 100 amp, into my garage. The main panel is on the outside wall of the garage. I was thinking of putting the sub-panel right next to the main panel only on the inside of the garage wall. I was going to mount the panel in between the studs and then drill though the one stud that is between the panels and run the appropriate wiring through the hole. From the sub-panel I am going to run 110 and 220 to 4 different locations in the garage through conduit. I am going to get a permit for this work. Some other electrical was run a few years ago and I am going to include it in the permit process. The city adds $35 to the permit for work that was allready completed. I will draw out everything before i go to get the permit. I am trying to find out if the location of th sub-panel is OK.

[Eric Roberge]

If you're pulling permits for the work then the town will inspect it, so you should be ok. Make sure there are no obstructions above or below the panel. Follow the National Electrical Code for distance from the floor to the bottom of the panel, GFCI requirements, etc. Some counties/states have their own interpretation of the codes, so a little research could save you time in the long haul.
Sounds as though you have it well thought out! Good luck!

[Rob Russell]

Location sounds fine. I'd run a short piece of 1 1/4" PVC conduit between the panelboards and pull individual conductors. You could run #3 copper THHN/THWN for the (3) current-carrying conductors and #8 copper THHN/THWN for the equipment grounding conductor.

You can go smaller if you don't need the 100A subpanel.



Is the garage finished / drywalled?

[Alan Greene]

Rob, The garage is finished inside. I have been playing with the idea of going down to 50 amp. I am the only one using the equipment so 100 amp is probably overkill. Not sure yet.

Eric, I am not sure what the height requirement is. I figured I would be safe putting it at the same height as the main panel.

[Rod Sheridan]

Rob, The garage is finished inside. I have been playing with the idea of going down to 50 amp. I am the only one using the equipment so 100 amp is probably overkill. Not sure yet.

Eric, I am not sure what the height requirement is. I figured I would be safe putting it at the same height as the main panel.

50 amperes will be more than you will probably need.

My shop is fed from a 35A feeder.

1.5 HP cyclone, the remainder of the machines range from 3 to 4 HP, so they are fed from one 15 A circuit, the cyclone from another 15A circuit.

My lighting is from the main panel, not the sub-panel.

If you're like me, it's the cyclone and one piece of machinery at a time since I work alone.

My shop is in the basement so I have no extra heating or cooling loads.

Regards, Rod.

[Rob Russell]

The garage is finished inside. I have been playing with the idea of going down to 50 amp. I am the only one using the equipment so 100 amp is probably overkill. Not sure yet.

With finished walls, unless you plan to fish all your wiring through the walls, you might consider surface mounting the panelboard in your garage. You can then easily run surface-mount conduit (like EMT) for your circuits.

You could do a 60A panel and use #6 and #10 copper to save some money. Still, you're running such a short distance between the panelboards that it's not going to cost that much difference to run the larger panelboard. I assume that you have 200A or larger main service.



Eric, I am not sure what the height requirement is. I figured I would be safe putting it at the same height as the main panel.

That works just fine.

The "working space" you need to keep clear is floor to ceiling, 30" wide and 3' deep in front of the panelboard.

[Roger Frazee]

Only thing I can add to the already good advice is that this will be a sub panel located in the same structure that the service equipment panel is located. Your having it inspected the feeder to the sub-panel must be 4 wires 2 hots, one neutral, and a equipment ground. You need to isolate the neutral from the ground so that the metal of the panel and the equipment grounds are not bonded to the neutral. This varies on how you do this from panel to panel. If you know the panel you would like to buy we can tell you how this is done.

Also if you choose a 60 amp feeder and conduit you will need to have color configuration for the neutral and hots and ground. Hots can be black, neutral must be white, ground green.

For 100 amp feeder 2 blacks or black and red for the hots, and you can use black for the neutral and white phase tape (electrical tape) to identify it at both ends., just stay with green for ground.

For a feeder protected by a double pole circuit breaker 30 to 60 amps use #10 for your ground.

For 100 amps use #8 green

As Rob said the distance is very short either 60 or 100 amp feeder isn't going to be much difference in cost. The breaker will be most of it. A 100 amp double pole will be 35 to 45 bucks at the big box. A 60 will be 12 to 15 bucks.

Your sub is allowed to be main lug but you can use a main breaker in it if you like for a disconnect....thats up to you.

One more thing your panel will need to be rated 100 amps otherwise you will not get enough circuit breaker spaces to do what your wanting. You do not have to feed it 100 amps you can feed it any thing up to 100 amps or less. Generally speaking main lugs for 100 amp panels will accept a minimum #6 awg wire so give it at least a 60 amp feeder no less or the lugs won't be rated correctly.. the only way to go less than 60 amps would be to use a backfed main breaker in the sub panel if it accepts a hold down kit. So if you want a means of single throw feeder disconnect at the sub keep these things in mind. Other wise just go with a main lug only 100 amp panel using the breaker at the main panel for you protection and feeder disconnect.

If you have any questions on the seperation of neutral and ground post back.

Hope I kept this simple

[Ron Knapp]

I just finished installing a 50 amp but I already had 15 amp service which I left alone. if you do 50 or 100 be sure to get a sub panel with extra breaker slots.

[Matt Meiser]

I'll second Rob's recommendation for a surface mount panel in the shop. New equipment acquisitions may require future wiring changes which are much easier if the panel is on the surface.

[Alan Greene]

Ok, to answer some of your questions, and ask a few more. The panel I have is a GE DEH-40537. It came with a 100 amp main breaker and 4 20 amp breakers as well as a 30 amp double breaker (240v). It is an indoor type "PowerMark Gold Load Center" http://www.geindustrial.com/publibrary/checkout/Installation%20and%20Instruction%7CDEH-40537%7Cgeneric.

I have a 30" wide space from the ceiling down to 3' feet above the floor. The 3' feet in front is OK. There the water softener salt container resides. This is the only place in the garage where this can mount due to cabinets that are installed on all 3 walls. If I do this without a permit what are the ramifications of that? My preference is to get the permit.

I do have a 200 amp service.

I am going to surface mount and run EMT.

Any suggestions will be much appreciated.

[Rob Russell]

The first thing is that you can't have the water softener in the floor space in front of the panelboard. Any competent AHJ (Authority Having Jurisdiction, aka the Building Inspector) will fail that installation.

The risk you run is that, when you go to sell the house, you will be required to bring the electrical installation up to the then (future) current code if its discovered that the subpanel was not permitted/inspected. If you install now to code, then that installation is "grandfathered" against future code changes. There may be there risks that I'm not aware of.

I would not install a subpanel without a permit, especially a subpanel in a garage that's going to have a whole bunch of EMT sprouting out of it.

[Alan Greene]

Rob, I will try to get a picture. The softener salt container will not be in front of the sub-panel but to the left of it. It is about a 24" width instead of 30. My preference is to get the permit. I think I read somewhere that it can effect your house insurance as well, especially if a fire starts in the work done without the permit.

[Rob Russell]

One big reason to pull a permit and have the work inspected is that your AHJ can approve installations that don't meet the exact requirements of the electrical code as adopted in your area. If the only place you can put the panelboard is in that location, they may allow it.

I'd take some pictures of the entire garage into the building department when you apply for the permit and ask, up front, about the "working space" requirement. Going in knowing that you need an exception approved and what the rule is that you can't comply with shows that you've got an understanding of the code that most folks won't have.

[Alan Greene]

Rob, I am going to take the pictures later today.

[Peter Quadarella]

By the way, I run off a 30amp sub panel and don't have any issues running a 3HP jointer with a 2HP dust collector and lights and assorted dodads. Haven't tried it with a compressor at the same time tho.

[Alex Shanku]

Either 100 or 60 will be a lot.

I have 200amp service in my shop and only use about 1/4 of my panel.