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-   -   Single breaker vs double pole breaker for MAIN (http://www.diychatroom.com/f18/single-breaker-vs-double-pole-breaker-main-57206/)

tuckerz 11-14-2009 09:04 PM

Single breaker vs double pole breaker for MAIN
 
Today's electrical service panels are usually one main breaker at the top with a 100amp or 200 amp breaker for the main service breaker. Simple enough.

Old house (1970) I am working on has the main feed coming into a bus, lower part of the bus connecting to two wires which run to a 60Amp double pole breaker which feeds all the other breakers.

So the question is, is this considered a 60Amp panel or 120Amp panel compared to today's single breaker's ?

nap 11-14-2009 10:03 PM

Not sure I understand what you have.

Does one breaker (the 60 amp) turn off everything?

If so, you have a 60 amp service. The "single" breakers you speak of for current panels are 2 pole breakers. Some of them have wide handles, some have a single width handle, but they are still 20 pole breakers.

joed 11-14-2009 10:06 PM

Sounds like a split buss panel. One of the breakers in the top part of the panel feeds the lower part. Also some of the 240 volt loads like dryer range heater are fed off the upper buss as well. The size of this panel is not as easy to determine and normal panel. In this case you can add up the breakers in the upper half to possibly determine the service size.

tuckerz 11-14-2009 10:09 PM

Quote:

Originally Posted by nap (Post 353215)
Not sure I understand what you have.

Does one breaker (the 60 amp) turn off everything?

If so, you have a 60 amp service. The "single" breakers you speak of for current panels are 2 pole breakers. Some of them have wide handles, some have a single width handle, but they are still 20 pole breakers.

The one breaker, 60 amps on each leg, turns the whole panel off. This breaker is not on the top of the panel like today's breaker's, it is fed from wires at the bottom of the bus and is the 2nd breaker down on the left hand side. I know, Thomas Edison crap and it should be updated probably.
Hard to believe this is only a 60 amp service. Why wouldn't if be 120 amps, 60 amps each leg ?
In comparison, a 200amp panel of today is fused how much on each leg ? 100 or 200 amp ?

kbsparky 11-14-2009 10:11 PM

You have an old split bus panel. The ratings of the mains are usually written on a label somewhere on the guts or cover of the panel.

There is no single "main" breaker --- you can have up to 6 "disconnects" with those.

Outlawed by the 1984 NEC, they were used extensively in the 1970's and early 1980's. Mainly because they were dirt cheap, without the cost of a real main breaker.

Scuba_Dave 11-14-2009 10:13 PM

A 100a or 200a panel today is 240v & may have one MAIN breaker handle but it turns off 2 hots
Rated 100a 240v or 100a 120v each hot, same thing for 200a

A 60a double pole breaker is usually 60a 240v, 60a 120v each leg/hot

Post a pic

spark plug 11-14-2009 10:24 PM

Quote:

Originally Posted by nap (Post 353215)
Not sure I understand what you have.

Does one breaker (the 60 amp) turn off everything?

If so, you have a 60 amp service. The "single" breakers you speak of for current panels are 2 pole breakers. Some of them have wide handles, some have a single width handle, but they are still 20 pole breakers.

You probably meant "2-pole". Not 20 pole! Speaking of "Split Buss". The old residential 24 breaker FPE panels did not have "Intertwined" buss. Meaning that if you "Plugged" 2 breakers next to each other you wouldn't get 240v. You only got 2 spots for 240v. In the center, top and bottom.

tuckerz 11-14-2009 10:41 PM

Quote:

Originally Posted by Scuba_Dave (Post 353226)
A 100a or 200a panel today is 240v & may have one MAIN breaker handle but it turns off 2 hots
Rated 100a 240v or 100a 120v each hot, same thing for 200a

A 60a double pole breaker is usually 60a 240v, 60a 120v each leg/hot

Post a pic

Will do tomorrow.

Outlawed ? Holy crap. Is it really that bad ????
What really sucks even more is this is Al wiring which I am selectively upgrading to Cu on some circuits.

nap 11-14-2009 11:30 PM

Quote:

Originally Posted by spark plug (Post 353236)
You probably meant "2-pole". Not 20 pole! Speaking of "Split Buss". The old residential 24 breaker FPE panels did not have "Intertwined" buss. Meaning that if you "Plugged" 2 breakers next to each other you wouldn't get 240v. You only got 2 spots for 240v. In the center, top and bottom.

Yep, sure did.

and I had thought about the split bus. That is why I asked for the OP's explanation of the 1 breaker turning off everything.

It still sounds like a split bus but...:huh:

to tuckerz:

a 2 pole 60 amp breaker still only allows 60 amps of current therefore, a 60 amp breaker/service/ what have you.

spark plug 11-14-2009 11:38 PM

Quote:

Originally Posted by nap (Post 353247)
Yep, sure did.

and I had thought about the split bus. That is why I asked for the OP's explanation of the 1 breaker turning off everything.

It still sounds like a split bus but...:huh:

to tuckerz:

a 2 pole 60 amp breaker still only allows 60 amps of current therefore, a 60 amp breaker/service/ what have you.

That's a mistake a lot of amateurs make. I did before I was initiated:laughing:! It's "Simple math, isn't it? if one side/pole can pull 100 amps., then two poles can pull 120?, NO?! The answer, obviously is that each side can ONLY pull 100amps.

AllanJ 11-15-2009 08:32 AM

A panel where the feed goes first into a maximum 60 amp breaker is called a 60 amp panel, whether the breaker is single or double pole. No one component (subcomponent if you insist) inside the panel is (should be) subjected to more than 60 amps.

When a 120/240 volt feed (two hots and a neutral) comes into the panel, the breaker is supposed to shut both off at the same time hence the present requirement of a double breaker.

Even in the distant past, it was rare to find a main panel for 120 volts only (one hot and a neutral) for more than 40 amps.

Quote:

Old house ... has the main feed coming into a bus, lower part of the bus connecting to two wires which run to a 60Amp double pole breaker which feeds all the other breakers.
What else can be connected to the bus between the main feed and the 60 amp breaker unit?

Nowadays we can have a main panel with more than one (up to six) "main" disconnect switch or breaker unit, for respective subpanels. There should be a rating in amps for the incoming feed which would of course be greater than the rating for any individual breaker unit.

tuckerz 11-16-2009 06:42 PM

Talked to a city inspector today and he clarified it.
The panel is a split panel consisting of a top and bottom section.
The top section which contains 6 double breakers each connected directly to the line without an overall main breaker in series.
The bottom of the bus bar has wires that run to two 60A breakers, which feed the lower section of the panel.
Thus effectively the panel is 60A on the lower plus the top section breakers added together, which in this case it is a 150 amp panel.
If you look at it with the breakers in, it looks like just one panel, not split in any way noticeable.

Thanks guys who were on to it with the split bus post.


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