Subpanel install question

Hi All,

I'm installing a subpanel in my garage and I have to use conduit for the wires since all is drywalled. My current main panel is on the right side wall as you drive into the garage(18x18)

I don't know where all the equipment will go yet but I want to do some of the electrical work before I move. The question is where would you locate the subpanel?

Would you put it on the same wall as the main which has 8 slots left? This would save some on the heavy #6 THNN wire I'll buy but would make wiring circuits on the left side wall longer.

Or would you put it on the left side wall which would be opposite the main panel. This would make it easier to wire circuits on that left wall since the subpanel would be right there. Otherwise I'd have to bring all my circuits over from the subpanel on the right side wall.

Thanks for any thoughts on this.

Alan in Md.

Well sort of a toss up there. As I think one cost will cancel the other out.

But I think code require them to be next to each other. That way anyone can see the that there are two panels. No one throws a main thinking the whole house is dead and the grabs a live wire because it comes off another panel that is feeding that panel.

If you have 8 slots left I would just use those. That could give you (2) 220V and (4) 110V circuits. That should be more than enough in a one man shop. I would say you get buy with )1) 220V and (2) 110V circuits if your not using a dust collector. You could save some money this way.

Not sure about code on that. I would think you could put the sub anywhere. My main was in a basement and I had to run about 80-feet of heavy wire to my garage sub-panel. Fully inspected too. I would probably put them next to each other anyway. That way you'd have all the breakers in one area. No quick decisions in case of emergency, just run to the panels!

To prevent the confusion on mains per above, I used a "main lug" subpanel. No main breaker in it, as the 240 subpanel breaker is back at your main panel.

You can put the sub where ever it is best.

Quote:

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Originally Posted by Jeff Horton

But I think code require them to be next to each other. That way anyone can see the that there are two panels. No one throws a main thinking the whole house is dead and the grabs a live wire because it comes off another panel that is feeding that panel.

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Jeff,

Sorry for being a bit curt, but I think you're wrong. There is nothing that I know of in the NEC that says the subpanel has to be right next to the service equipment. If you're going to make a statement like that where you're quoting "the code" - please be prepared to cite the actual code section. Otherwise people can make statements because they may think the statements are sensible, but they don't match up with what the code calls for.

Alan,

One thing to consider is that you have to keep the floor space in front of the subpanel clear for "working space" of 30" wide x 36" deep. That's per the NEC, article 110.26 and the associated table. You can't have storage overhead in that area either. I'd think that locating the subpanel next to the main panel would reduce the restrictions you'll have with placing stuff in your shop. If you put the subpanel on the other wall, that means you can't have stuff running all the way along either wall and that could be a real hassle for you in terms of shop layout.

Rob
Addy protocol: unlicensed, but experienced homeowner electrician

Quote:

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Originally Posted by Jeff Horton

Well sort of a toss up there. As I think one cost will cancel the other out.

But I think code require them to be next to each other. That way anyone can see the that there are two panels. No one throws a main thinking the whole house is dead and the grabs a live wire because it comes off another panel that is feeding that panel.

If you have 8 slots left I would just use those. That could give you (2) 220V and (4) 110V circuits. That should be more than enough in a one man shop. I would say you get buy with )1) 220V and (2) 110V circuits if your not using a dust collector. You could save some money this way.

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Actually using the method of wiring shown in Oct 2005 Popular Woodworking article "Efficent Shop Wiring" you can have 4-220V circuits and 8- 110V circuits. You use a double pole breaker with a neutral to feed both 220 and a pair of 110 outlets. Neutral only feeds the 110 outlets. Two hots, one neutral, and a ground per breaker.

Quote:

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Originally Posted by Rob Russell

Jeff,

Sorry for being a bit curt, but I think you're wrong. There is nothing that I know of in the NEC that says the subpanel has to be right next to the service equipment. If you're going to make a statement like that where you're quoting "the code" - please be prepared to cite the actual code section.

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Rob, I said I think it is code, I didn't say it was code.

Life will be much easier if you put the subpanel next to the existing panel. You really don't want to run the feeder all the way across the garage, especially at the current prices.

That being said, if you have 8 slots left in your main, then why not hold off on the subpanel until you actually need it. You have nothing to lose because the garage is already sheetrocked. It's not like you can't go back and put one in later, aspecially if you place it next to the existing panel.

Eight circuits in a garage is more than you will need to run a shop. It's not as though you can have five people working in there at the same time. Even if you have 100 tools, you can still only operate one or two at a time. I have an 1800 sq ft shop, and if I had to, I could run the whole thing on 8 circuits.

P.S. Bruce, your information is not correct regarding doubling the circuit capacity. Using 1/2-height breakers will double the capacity (if they are available for the panel), but using a shared neutral will not gain you any breaker capacity.

Rick,

I'm not an electrician, but I've looked in the box. Two circuits each for 220V, am I right? My window AC takes two, DC takes two, table saw (I don't have, but would/will have a 220V bandsaw) takes two. Lights and freezers are on the main garage circuits, so they don't count. But that is 6 of those eaten up in a hurry without anything else counted. I can see that some auxillary lighting and such could come close on those 8 slots without any extra workers. Just thinking about it, since I ain't in the "electrician's box".

Also, my electrician wired in 9 knockouts when he setup the garage for me including one he labelled "spore". I think that means the same as "spare", but don't know if that means a spare breaker or if something is connected. Maybe it is my spore circuit, and I don't even know if I have any spores. I'll ask him next time he comes in. I had room in the main panel, so...

David

Quote:

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Originally Posted by Rick Christopherson

Life will be much easier if you put the subpanel next to the existing panel. You really don't want to run the feeder all the way across the garage, especially at the current prices.

That being said, if you have 8 slots left in your main, then why not hold off on the subpanel until you actually need it. You have nothing to lose because the garage is already sheetrocked. It's not like you can't go back and put one in later, aspecially if you place it next to the existing panel.

Eight circuits in a garage is more than you will need to run a shop. It's not as though you can have five people working in there at the same time. Even if you have 100 tools, you can still only operate one or two at a time. I have an 1800 sq ft shop, and if I had to, I could run the whole thing on 8 circuits.

P.S. Bruce, your information is not correct regarding doubling the circuit capacity. Using 1/2-height breakers will double the capacity (if they are available for the panel), but using a shared neutral will not gain you any breaker capacity.

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Quote:

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Originally Posted by Jeff Horton

Rob, I said I think it is code, I didn't say it was code.

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Jeff,

My point is - if you're going to cite the NEC - reference the article. Even saying "think" is making a statement about a rule that you believe is in the electrical code. Too many folks do that based on what they think makes sense, something they read on a forum or someone told them. That's how misinformation gets propogated. A good example of misinformation would be circuit size requirements for machinery and all the posts around "you need this size circuit for a 5 HP tablesaw".

Does it sound like I have ... hmmm, what's an expression I can use according to the SMC TOS ... a "thorn in my toe"? Yep. Citing the code when one can't bugs me, and I'm not even a licensed electrician. I'd be interested to know how the "real" sparkies feel about people using "the code" as an inappropriate basis for making statements.

Please know that I don't see referencing specific articles in the NEC as an "I know better than you" sort of thing. I see it as a way of keeping myself honest - as a "If ya can't provide the article number, ya shouldn't cite 'the code' as a means of supporting a statement" sort of thing.

Rob

rob, jeff didn`t cite code.....he clearly stated that he "thought" it was code.......correcting his assumption is fine but for heavens sake he didn`t suggest doing something dangerous or even inappropriate. so why jump down his throat? most folks are going to use common sence when messing with electricity and if they`re unsure they`ll either ask or hire an electrition. the original poster posed a valid question and the correct answer according to code is that the subpanel doesn`t have to be next to the main.....the diatribe you expounded sounds more like a third grade teacher admonishing johnny than adults on a woodworking forum...02 tod

Tod,

The reason I got ornery is because people read things on forums like "I think it's code", misinterpret it and then you've got misinformation floating around.

The problem is that electricity can kill faster than a kickback can and misinformation can lead to that.

The code is generally not a gray area - it either is or isn't in the code. If you want to say that you "think" something's in the code - take the time to look it up.

Sorry if I come off as being hard-nosed about this. You say this is an adult forum and I agree. Part of being an adult is - in my opinion - being especially careful about what we post on these electrical threads. I see the honiss as being on the poster - when referring to "the code" - to "know" and not "think" that what they're posting is valid and be able to back that up with a code cite. Part of the problem is that the professional electricians generally don't participate in these threads - it's we who are amateurs that participate. In my mind, that makes it that much more important that anyone posting be sure that their information is accurate.

Now - in the specific case of whether the subpanel has to be next to the main panel or not - is that a "deadly" sort of mistake? Nope. My reaction was based on the principle of "think" vs. "know" - that's all.

Off soapbox.

Rob
Addy protocol - unlicensed, but experienced homeowner electrician

HEY....no fighting....Dad's going to come in and take all our posts away. Then MOM is going to make us eat slugs from the garden. I hate eating slugs.




:D :D :D

Thanks for your thoughts on this guys. Now let's behave here! :o It's getting to sound like one of those F vs. E debates. :( I do appreciate the info. you've given me though.

Quote:

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Originally Posted by Rob Russell

...The reason I got ornery is because people read things on forums like "I think it's code", misinterpret it and then you've got misinformation floating around.....

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Rob, Even though you appologized for being "curt", I did not find your posting to be curt. You stated the very sentiments I was about to post until I saw that you already had. If someone does not know the NEC, then the word "code" shouldn't even be in their posting, because it leaves the perception that some knowledge exists.

There is another thread on this forum where this very thing is happening. Someone else will read the statement and assume there is validity to it, so they will repeat it as though it was fact, and they won't use the words "I think".