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Peoria, Arizona
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Lafayette, Louisiana
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 Six Disconnect Rule
[#2] Posted: 08/06/2011 - 09:58:48 AM |  |  |
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A panel with one main breaker cannot be rated any less than the size of that main breaker.
If there's more than one main breaker then the rating of the panel must be adequate for the loads on it, as revealed by the load analysis. This calculation is detailed in the codes and is usually performed by the electrician.
In installations having more than one main, it's common for the numerical sum of the main breaker ratings to exceed the rating of the panel.
Marc
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"If Guam gets too overpopulated, it might tip over."
Congressman Hank Johnson (D) GA |
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Gaston, Oregon
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Peoria, Arizona
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Six Disconnect Rule
[#4] Posted: 08/06/2011 - 5:58:51 PM | | |
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Thanks guys.
Jeff
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Victoria, British Columbia
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Lafayette, Louisiana
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Six Disconnect Rule
[#6] Posted: 08/07/2011 - 06:05:46 AM | | |
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| Quote: Originally posted by Marc
A panel with one main breaker cannot be rated any less than the size of that main breaker.
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Say what?
If there happens to be a 200 amp main breaker in your panel, but it is fed by a 100 amp breaker from another panel, then how do you rate the panel?
If a main breaker is fed by another breaker then this 'main breaker' isn't technically the main breaker for that electrical installation.
Marc
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"If Guam gets too overpopulated, it might tip over."
Congressman Hank Johnson (D) GA |
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Prattsburgh, New York
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Victoria, British Columbia
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Six Disconnect Rule
[#8] Posted: 08/07/2011 - 2:41:31 PM | | |
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Quote: Originally posted by Greg BoothQuote: If a main breaker is fed by another breaker then this 'main breaker' isn't technically the main breaker for that electrical installation.
Marc "technically" correct, but practically........... a home served by a (sub)panel with a 200A breaker, fed from a 100A breaker at a meter bank..........that 200A breaker will be considered the "main". I see this exact set-up in manufactured home communities often. The community operator generally will not allow "their" breaker to be used as a disconnect by the homeowner/service folks. ..........Greg
I had to break the bad news to an older lady who was planning to replace the old oil furnace in the mobile with an new electric unit. Sorry, this is not really a 100 amp service. "But it says it is". 
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Lafayette, Louisiana
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Six Disconnect Rule
[#9] Posted: 08/07/2011 - 6:20:19 PM | | |
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Quote: Originally posted by Greg BoothQuote: If a main breaker is fed by another breaker then this 'main breaker' isn't technically the main breaker for that electrical installation.
Marc "technically" correct, but practically........... a home served by a (sub)panel with a 200A breaker, fed from a 100A breaker at a meter bank..........that 200A breaker will be considered the "main". I see this exact set-up in manufactured home communities often. The community operator generally will not allow "their" breaker to be used as a disconnect by the homeowner/service folks. ..........Greg
It's misleading to refer to a feeder breaker as a main breaker, though I can understand how some people might make that mistake.
Marc
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"If Guam gets too overpopulated, it might tip over."
Congressman Hank Johnson (D) GA |
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Victoria, British Columbia
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Six Disconnect Rule
[#10] Posted: 08/07/2011 - 8:42:37 PM | | |
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Thanks. Marc. If you called the main breaker a service disconnect, it would be less confusing. I know we are just hashing over different terms for the same thing.
I knew what you meant, but it could be interpreted wrong if someone confused the main breaker in a service panel with a 'main' breaker in a subpanel.
In a condo or a mobile home, we generally in my area will call the feeder breaker a main.
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Lafayette, Louisiana
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Six Disconnect Rule
[#11] Posted: 08/08/2011 - 05:27:04 AM | | |
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Agreed. 'Service disconnect' is a better term for it.
Marc
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"If Guam gets too overpopulated, it might tip over."
Congressman Hank Johnson (D) GA |
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Comer, GA
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Six Disconnect Rule
[#12] Posted: 08/09/2011 - 2:33:46 PM | | |
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Nitpicking as usual, I'd point out that the "six" rule applies to motions, not discos. Grouped discos are usually found in commercial applications, not houses, unless it is split panel.
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Gaston, Oregon
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Six Disconnect Rule
[#13] Posted: 08/09/2011 - 9:21:28 PM | | |
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| Quote: Originally posted by Jim Baird
Nitpicking as usual, I'd point out that the "six" rule applies to motions, not discos.
The only time it applies to motions is with multiwire circuits. Otherwise, it does, indeed, refer to breakers or switches.
Heck, I can turn off 40 individual breakers with one "motion" or, to use the code term, "operation of the hand."
Check out 230.71(A):
General. The service disconnecting means for each service permitted by 230.2, or for each set of service-entrance conductors permitted by 230.40, Exception No. 1, 3, 4, or 5, shall consist of not more than six switches or sets of circuit breakers, or a combination of not more than six switches and sets of circuit breakers, mounted in a single enclosure, in a group of separate enclosures, or in or on a switchboard. There shall be not more than six sets of disconnects per service grouped in any one location.
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Jim Katen, Oregon
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