200 Amp panel selection question

[Bob Cooper]

I have the new workshop framed. It's connected to the house via a 10' long covered breezway. When i built the house, I had the electrician coil up enough cable to run a 100 Amp circuit to the shop...that cable is routed through the roof of the breezeway.

My question is one of a panel in the garage/workshop. I'd like to use a 200Amp panel just to give me the extra space. Naturally it will connect to a 100Amp breaker in the house panel. Any issues with this? Also i'm assuming i would use a "lug" panel vs. a "main" panel. Agree? But woudl either one be OK?

Right now i'm thinking of buying the Square D QO series from Lowes unless there's a good online source (i looked and didn't have great luck).

[Charles Lent]

There's nothing wrong with using a 200 A rated panel. I would choose the lug panel over one with a main breaker, because you already have a 100 amp breaker for this sub panel located in your main panel and cable running from it rated to carry 100 amps. Just make sure that the breaker and cable are correct for this and that the cable has 4 conductors (2 hot, neutral, and ground). You DO NOT join the neutral buss in this new panel to ground (do NOT install the jumper or green screw). This is only done in one place, at the main panel. Treat neutral and ground as if they are separate circuits in the garage/shop.

Charley

[Patrick Maloney]

I used the Square D main panel, I think 200 amp, just because it was cheaper. It was the combo that included the breakers, too. There's no sense in spending more money for no reason.

[Jim Neeley]

+1 on Charlie's description, especially NOT joining the neutral and ground at the sub-panel.

Two thumbs up, Charley!

[Larry Edgerton]

I used a QO 200 in my house feeding a 100 amp QO in the car garage. The 100 amp sub has just as many openings as the 200, so it was not a problem. I am using the garage temporarily for a shop until I get my real shop done so am running up to 3 motors off of a phase converter totaling 21 hp at a time. No problems.


My old shop had a Cutler Hammer panel, but I went with a Square D this time because in my area finding breakers is hard with a Cutler Hammer, and Square D's are everywhere.

Larry

[Anthony Whitesell]

You can use either the lug or main panel as long as the break from the main panel is smaller or equal to the current rating for the wire between the panels. IMO, the Square D QO line is tops. It's been around a long time. I find it a lot in retail and commercial buildings that I have worked in. Never seen a Square D Homeline in any building.

Check out SuperBreakers.net. I purchased the QO140M200 (1ph 40 slots 200A) from them. Free 200A Main breaker, cover included, and free shipping. Listing today for $170. The QO140L200G (lug) is listing at $115. To buy the 200A breaker later will cost $110.

[Rodger Kanis]

I picked up a the Square D QO 100 Amp main breaker panel (not lug-only) panel, 30 spaces, at my local Home Depot. It came with the 100 A main breaker and I think five 20 A breakers (single pole). The price escapes me at the moment, but I think it was $130ish. This was replacing an aged and damaged main panel in my house. We elected to not spend the cash right now for upgrading to 200 A, and honestly, don't really need to (per my electrician).

For convenience, if cost isn't an overriding factor, it can be nice to have a main breaker for the sub-panel so you don't have to walk back to the main panel to turn it off when doing electrical work in your shop. Just a thought. Again, depends upon budget, distance, etc.

[John Lanciani]

Nothing at all wrong with Square-D QO, (I'd never use homeline,though), but I'd personally use the same as whatever you already have in the house so that the breakers are interchangable. That way any spares that you keep on hand will fit either panel. I'd also use a main breaker panel for the convenience of being able to turn it off to add or remove circuits without having to go to the house to kill it.

[Christopher Dopp]

I bought a Square-D main 100Amp panel from home depot for my detached garage sub panel (which is actually only 60 amps). I like having the main breaker to switch and shut off all circuits in the garage instead of having to go back into the main house and flip the breaker in the main panel. I bought a lock for the sub panel cover so I can shut off all circuits (or even just the ones for the larger machines) and lock the panel to prevent anyone from turning on the tools in my absence (like my daughter who is almost 5). It wasn't that expensive and gives me a little more piece of mind.

[Bob Cooper]

Anthony writes "You can use either the lug or main panel as long as the break from the main panel is smaller or equal to the current rating for the wire between the panels."

question...i'd like to use a 200A panel in the shop...just due to the extra spaces; howeve the wire and breaker in the main panel will only support 100Amp. i see no safety issue since the current will be limited to 100A but is this considered a code violation? I wouldn't expect it but curious.

To do understand the issue about having ground and neutral only connect at one spot and yes i have 4 conductors going back to the main panel.

[Rod Sheridan]

I would suggest checking with the AHJ as to whether a main disconnect device is required for your sub panel.

Regards, Rod.

[Anthony Whitesell]

Anthony writes "You can use either the lug or main panel as long as the break from the main panel is smaller or equal to the current rating for the wire between the panels."

question...i'd like to use a 200A panel in the shop...just due to the extra spaces; howeve the wire and breaker in the main panel will only support 100Amp. i see no safety issue since the current will be limited to 100A but is this considered a code violation? I wouldn't expect it but curious.

To do understand the issue about having ground and neutral only connect at one spot and yes i have 4 conductors going back to the main panel.

As far as I understand the code and from the electricians it is not. It does look weird. As mentioned your AHJ will also have a vote. Realistically, whats the difference between feeding from 100A breaker/wire into a panel with a 200A breaker versus feeding into into a panel with no breaker?

I think this discussion just allowed me to comprehend one of the specs of the QO140M200 panel. Specifically, the item that says "Convertible Main" I wonder if that means the 200A breaker that come with the panel can be removed to convert the panel to main lugs. Anyone?

P.S. Square D tech support is rather helpful if you can find their phone number on the website. I recall it is rather buried.

[Rob Russell]

As far as I understand the code and from the electricians it is not. It does look weird. As mentioned your AHJ will also have a vote. Realistically, whats the difference between feeding from 100A breaker/wire into a panel with a 200A breaker versus feeding into into a panel with no breaker?

The difference is that having a breaker in your subpanel gives you a disconnect as has already been mentioned. That allows you to kill power to most of the panelboard without going back into your house to kill power at the main panel. If you're adding new circuits, it might be nice to kill power to the panelboard instead of "working hot". Obviously the conductors on the supply side of the main breaker will be hot, but there's not much you'd likely be doing up in that part of the panelboard.

[Don Jarvie]

I have the full panel in my garage with a main breaker like Rob is describing above. Easy to kill the power in the garage instead of walking back to the house.

[Matt Meiser]

Nothing at all wrong with Square-D QO, (I'd never use homeline,though), but I'd personally use the same as whatever you already have in the house so that the breakers are interchangable. That way any spares that you keep on hand will fit either panel. I'd also use a main breaker panel for the convenience of being able to turn it off to add or remove circuits without having to go to the house to kill it.

+1 on this! My house has a Westinghouse (Cutler Hammer) panel, the shop has a Murray (Siemens) panel, and there's a no-longer-used spa panel outside that is GE because that's all that was readily available in a spa panel. What a pain. If the house panel wasn't in a finished wall, I'd consider changing it out to Siemens when we eventually put in a generator.

I vote for the main breaker for easy disconnect reasons.

The problem with a 100A panel in a shop is that you can quickly run out of room since 220 circuits take up twice or even 4x the space of a 110 breaker.