A little electricity 101 if you please

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By code, it has to have at least one

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RBM wrote:

But by code, the main doesn't necessarly kill everything in the panel.
Tom J who has 1 of thousands like that
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The Nec requires up to six service disconnects. If you only have one , it kills everything. If you have more than one, you need to shut them all to kill everything

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In these thousands of panels like mine that was installed in the '60's and are still in production and being sold today, the breaker marked MAIN only cuts off the 110V circuits that are below it. All the 220V breakers above it and the buss for them is still hot when the MAIN breaker is off. None of the 220 breakers say MAIN, and even if they did, the buss bars are still hot. People that don't understand how panels are wired really need to get an electrician when it comes time to add things to the service panel.
Tom J
RBM wrote:

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Yep, that's a split buss panel, and all the breakers on top are "mains" and yes, that panel has main lugs and upper buss that is always live

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wrote:

20+ years ago I needed a new svc. panel. I looked at such split buss panels and recoiled. Installed the simplest imaginable 200a panel with "The One True Main" breaker and never regretted it.
As I recall, such panels weren't much more expensive than split buss. A professional electrician would do much better than I with split buss, but it's hard for me to imagine a complex job being easier with split buss, regardless of training/experience.
Just curious. Why were (residential) split buss panels so extensively used?
Cheers, Puddin'
"Life is nothing but a competition to be the criminal rather than the victim." - Bertrand Russell
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Haven't got a clue. I hate the damn things, not to mention how potentially dangerous they are. With a single main disconnect, say 200 amp, when your load reaches that point, it trips. With a split buss, you "could" have six 100 amp main disconnects on the same 200 amp service, depending upon the actual load in the building, presuming it's less than 200 amp. Thirty years goes by, countless DIY's , handy men, etc, and who knows what's actually being drawn through the service conductors
wrote:

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wrote:

Not exactly the response I expected.

Comprendere, senor.

And if one manually opens the main, barring a fault of a certain kind and/or a main breaker failure, one can expect that there is -no- power anywhere in the house (given a simple, single svc. panel application)?

And it can take (at least figuratively) 40 days and 40 nites to precisely figure out what's what in the circuitry? :-)
Your honesty is appreciated.
I'll assume split buss (residential) prevalence has *something* to do with "The Industry" until I have evidence to the contrary.
Thanks, Puddin'

"Life is nothing but a competition to be the criminal rather than the victim." - Bertrand Russell
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Puddin' Man wrote:

I have no definitive answer. What is (or was) the price difference between a 50 amp and 100 amp double pole breaker? If the latter is substantially more, that can potentially justify using a split bus panel.
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What brand of foreign assed panel is that? Never heard tell of such a thing.
--
Steve Barker




"Tom J" < snipped-for-privacy@earthlink.net> wrote in message
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Probably every manufacturer made them, but the ones I've seen most often are Federal Pacific, from NJ

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Mine is a Federal Pacific also, but the panel next door is the same form and it's a Square D and the replacement circuit breaker panel I'm installing next week that has the same form is a Square D. So it's not MADE them, because they are still being made.
Tom J
RBM wrote:

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I said "made" because not all manufacturers are still making them, least of all Federal Pacific

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Brian O wrote:

I know what was referred to and some person reading that would assume that ALL panels were dead inside when the breakers/fuses marked main were off/pulled, which is just not so in thousands of both old and new homes. killing the Main and then sticking a had in the box is asking for death and people that know little or nothing about electrical distribution panels need to be aware that there are differences.
Tom J
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Tom J wrote: > In these thousands of panels like mine that was installed in the '60's > and are still in production and being sold today, the breaker marked > MAIN only cuts off the 110V circuits that are below it. All the 220V > breakers above it and the buss for them is still hot when the MAIN > breaker is off. None of the 220 breakers say MAIN, and even if they > did, the buss bars are still hot. People that don't understand how > panels are wired really need to get an electrician when it comes time > to add things to the service panel. > > Tom J > Those are not still sold in the US because the US code now requires lighting and appliance panel boards to have no more than two disconnecting means. -- Tom Horne
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Thomas Horne wrote:

Really, they are not sold anymore? I don't think the installer stole the one that was just installed last week??
Tom J
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Tom J wrote:

All right I'll play your game. What is the manufacturer and the model number? -- Tom Horne
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Re "MAIN" - all service disconnects are required to be marked.

I looked that up earlier in the thread - NEC 408.36-A. What is the intent of "2"? Seems like that allows continued installation of the old "main and range" fuse panels with 2 60A pullouts, one for the plug fuses (or equivalent CB panels).
[Exception #2 specifically grandfathers old split bus service panels.]
-- bud--
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