Sub-Panel For Garage Workshop

[Vince Shriver]

First, I don't pretend to know much about electrical stuff. Going to have a 50 amp sub-panel installed in the garage. This never came up, but I thought I'd ask: Should the breakers be the GFCI type (breakers are all 20amp)? Thanks in advance, Vince

[David T gray]

only if you plan on watering your tools.

[Dan Rude]

First, I don't pretend to know much about electrical stuff. Going to have a 50 amp sub-panel installed in the garage. This never came up, but I thought I'd ask: Should the breakers be the GFCI type (breakers are all 20amp)? Thanks in advance, Vince

I would pass on the GFCI breakers. Use 20 Amp GFCI outlets to feed your 120v circuits. The 240v circuits do not usually need the GFCI since they are usually machine circuits. It will depend on NEC in your area, since ARC fault could be required though. Dan

[Ken Kortge]

Certainly you'll need to check with your local electrical code - call your local building department or inspector. I'm pretty certain that the national electrical code requires ground fault breakers or receptacles in the garage,outbuildings, and exterior, EXCEPT for locations that are not readily accessable - like for garage door openers or roof de-icer coils. They are also required for kitchen, bathrooms, laundry room, wet bar counters, unfinished basements, except for not readily accessable recepticles like alarm systems, crawl spaces, pool/spa areas. I don't think ground fault is required for 240V service.

These days arc fault breakers are now required in just about all places except outdoors, laundry rooms, unfinished basements, attics, garage spaces, and 240V service.

[Bill Space]

My understanding is that the GFI is required for a garage. Either attached or separate from the building.

I'm going to install an electrical subpanel in the self standing garage of the house next-door that I bought and I am renovating. It is going to be a 50 amp subpanel. I'm pretty sure I'm going to feed it using a 50 amp GFI breaker. That way all circuits I install in the garage will be GFI protected. A 50 ampere two-pole GFI circuit breaker costs about $100.

Years ago I met a man who was an electrician. He was using a drill outside his house somewhere, I think actually in his garage, And the drill shell became energized somehow, and he became frozen to it until he turned blue. I met him after-the-fact and he was obviously not the person he was before the accident happened.

The point being, why take the risk of not having GFI protection in a location where it really may help you?

Bill

[Bill Adamsen]

Definitely check the code and more importantly, your local building department. Likely the sub-panel will require separate grounding at the very least.

My barn required GFCI on the outside outlets and those in the basement (it's a cut-bank barn). Attached is a photo of my sub-panel and then to the left, the 3-phase panel energized by the RPC. The outlet just below the panel is GFCI protected probably because as the first outlet mounted I assumed it would be used frequently outdoors with an extension cord. That sort of "alternate use" might influence some of your thinking.

[Mike Cutler]

It will be up to your local building codes.

Re-think providing GFCI protection for the entire garage. There are types of machinery and drives that do not work properly on GFCI protected circuits. Principally the electronic speed and frequency control modules may not like that GFCI.
Some of the electronic control circuits for machinery are transformer isolated from ground, rectified to a DC voltage, that then feeds the control circuitry. These circuits are not at ground potential, and using a GFCI can cause problems with them. ( This is a very simplified explanation. I do this for a living, and have experienced many instances of GFCI protected circuits causing issues with control processors for equipment. )
It's better to GFCI protect at either the breaker for a circuit, or at the first receptacle in a string.

[Ken Kortge]

Re-think providing GFCI protection for the entire garage. There are types of machinery and drives that do not work properly on GFCI protected circuits. Principally the electronic speed and frequency control modules may not like that GFCI.

... but to do that I would guess you'd be required to electrically connect them directly - not using a recepticle. But as said check with your local building department. Don't be afraid to ask - they want you to do it right.

[Mike Cutler]

Ken

You be surprised at how many devices may, or may not, work properly that are plugged in. Washing, machines, dryers, automatic lamps, there are probably thousands of devices that may not work properly.
Generally at work they just trip the GFCI's, but we've had some that just "flutter" due to the noise induced by the active circuit in a GFCI device. I know it's "supposed" to be passive, but an O-scope says different. .
My personal take on wiring a shop is to put everything possible on some type of a plug to minimize code involvement. The "Code" stops at the receptacle.

[Bill Space]

My personal take on wiring a shop is to put everything possible on some type of a plug to minimize code involvement. The "Code" stops at the receptacle.

But doesn't the code also state that receptacles in a garage must be GFI protected?

Bottom line should be doing what is best to minimize potential injury. Personally I am up in the air about feeding the free standing garage with the 50 amp GFI circuit breaker, but I think in my case I will do that and take action later if a problem develops.

I do not intend to use variable frequency drives or washing machines or dish washers in the garage. But my inverter welder could be an issue I suppose if I use it there...

On the other hand, the 50 amp subpanel I put in the basement of that house, to supply mostly the kitchen, will have GFI breakers only where needed. It is fed by a standard 50 amp breaker.

Bill

[Arthur Fleming]

If the BUILDING is no longer being used to store a motor vehicle, there is a strong argument that it is no longer a garage. This will change the applicable NEC requirements. I tend to think you are better off with individual gfi breakers than a main breaker. Do you want your lighting to go out while you're cutting on the table saw? I understand about wanting to save expenses, but this cost may end up being higher than figured. I haven't opened the code book, but calling the building a work shop, and not a garage, may eliminate the need for gfi, or arcfault protection.

[Buck Williams]

If you're thinking about feeding the sub panel with one 50 amp GFI breaker, you should think about what would happen if that breaker tripped because of a ground fault. All of your lighting is out, you could be left in the dark with a half ripped piece of wood on your table saw, or for that matter any power tool running in the middle of an operation. Could be a dangerous situation if you reset the breaker without considering what happens when power comes back up. Might be better to have branch circuits GFCI protected, or at least have your lighting on a separate circuit.

[Bill Space]

Good points about the fact that if a ground fault occurs, and the subpanel is fed by a man 50 amp GFI breaker, then ALL POWER will power will be lost to whatever is connected to the subpanel.

Hopefully this is becoming a useful discussion for the OP, and not a thread hi Jack!

I specifically did not feed the subpanel in the basement of the house I mentioned with a 50 amp GFI breaker, for the reasons mentioned above.

In my case, I don't forsee using the circuits in the attached garage next-door for purposes like a woodworking shop. The OP may have different intentions for his space.

In any event, A 50 amp GFI circuit breaker costs about the same as three single pole 20 amp GFI circuit breaker's. Perhaps the OP Will find that single pole 115 V GFI breakers will satisfy his needs.

GFI circuit breakers are three or four times as expensive as standard circuit breaker's for a given size and type. But the protection that is offered is priceless should one find himself in a position to need it!

Personally, I'm not pushing for anyone to do this one where or another. I am sort of undecided in the direction I will go, but I'm pretty sure I will go with the 50 amp GFI feeding the subpanel in the garage I mentioned. I'm willing to live with the unexpected results of losing power to the garage in total, if during that event I avoid an unfortunate experience!

Bill

[Rick Moyer]

Someone I know had a garage that already had one circuit fed from the house panel (attached garage) that supplied an overhead light. Upon installing a sub-panel, GFi's were installed at the first outlets in the new circuits, thereby carrying protection down the line to other outlets on the same circuit. The original house fed circuit would keep a light on in the event of a trip from the sub panel. Not sure what code says about that, but it makes a lot of sense to me!

[Tim Hoyt]

In a former life I was a building inspector. I would have followed the NEC which would require GFCI protection for almost all of the 120 v recpts.

If it has a garage door, it's a garage, regardless of present use.

All that being said, I recently added a sub-panel to power up my basement woodshop. I discussed with the inspector if he would require GFCI protection. He said it would be a requirement. So I installed GFCI recpts with the intention of pulling them out after the final inspection if they started tripping. So far everything is still GFCI protected. I had expected to have problems, but have been pleasantly surprised with zero problems