split type bus?

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New EE

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California
I came across this residential panelboard that the main feeder comes into a 2P50A breaker that is labeled as "Main" but then there is another 2P50A breaker that is labeled as "Range". When I flip the 2P50A breaker that is labeled "main" it cuts everything off except the range which is connected to the other 2P50A breaker. I'm trying to figure out if the house has a 100 amp service or not. Thanks
 

hillbilly1

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North Georgia mountains
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I didn't see where you are located, but in Georgia, Georgia Power did this in quite a few homes, the panel will have a sticker on it saying that it is property of Georgia Power. It is a split buss panel. They are using the six switch rule. I think it was common in the Atlanta area in the 60's or 70's. I have seen a couple that way.
 

Dennis Alwon

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Looks like a 100 amp service to me. Split bus was very common years ago. The 200 amp split bus panel uses the 6 disco rule as the service disconnect. Usually a DP 60 fed the bottom section and all the others would feed other 240v items in the house such as dryer, range, water heater, etc

Sounds like the 100 amp unit just does the range and the breaker for the rest of the panel on top.
 

Little Bill

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Looks like a 100 amp service to me. Split bus was very common years ago. The 200 amp split bus panel uses the 6 disco rule as the service disconnect. Usually a DP 60 fed the bottom section and all the others would feed other 240v items in the house such as dryer, range, water heater, etc

Sounds like the 100 amp unit just does the range and the breaker for the rest of the panel on top.

This is very interesting. I have only seen (I think) a split bus in the handbook illustrations. Wouldn't there have to be 2 more sets of lugs fed from each of the breakers labeled range and main? There may be, the pic. just doesn't show the entire panel.
 

infinity

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New Jersey
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This is very interesting. I have only seen (I think) a split bus in the handbook illustrations. Wouldn't there have to be 2 more sets of lugs fed from each of the breakers labeled range and main? There may be, the pic. just doesn't show the entire panel.

The 2 pole-50 amp CB on the upper right feeds two conductors that feed the lower portion of the bus.
 

Little Bill

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No according to the OP that feeds the range circuit.


I only have an illustration to look at, actually 2 and I'm confused as to why 1 feed is for only 1 breaker (range). The diagrams I have show one set up as:
2 sets of wires tap off of main lugs and then to 2 DP breakers, 1 feeding lugs at the top of panel and the other feeding lugs at the bottom portion of panel.

The other set up is:
2P breaker from top half of panel feeds lugs for the bottom half of panel.

In the OP I can see how the 1 breaker turns off 1 section of panel but the one for the range must have some empty slots and only the range is connected to that portion of the panel.:confused:
 

Dennis Alwon

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Bill it is a main lug panel that feeds 2 dp breakers. One feeds the range and the other feeders another set of lugs on the bottom half of the panel that has breakers for the rest of the building. The bottom is a different bus then the top- they are not connected except thru the wire from the breaker on the right.

This is a 200 amp with 6 dp poles on the top half. I can't see how those wires are connected-- usually there is a block with lugs that fits in the empty space.

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infinity

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New Jersey
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I only have an illustration to look at, actually 2 and I'm confused as to why 1 feed is for only 1 breaker (range). The diagrams I have show one set up as:
2 sets of wires tap off of main lugs and then to 2 DP breakers, 1 feeding lugs at the top of panel and the other feeding lugs at the bottom portion of panel.

The other set up is:
2P breaker from top half of panel feeds lugs for the bottom half of panel.

In the OP I can see how the 1 breaker turns off 1 section of panel but the one for the range must have some empty slots and only the range is connected to that portion of the panel.:confused:

From the OP's description the MLO bus ends at the bottom of the top (L & R) two pole breakers. The second set of bus (split bus) begins at the third slot on both sides and continues down.
 

iwire

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Location
Massachusetts
With a 'Main and range' panel you have two service disconnecting means, the Main and the Range.

That being the case the rating of the service will be judged by the weakest link of the meter socket, service conductors, panel bus rating or the combined rating of the disconnecting means whichever is less.
 
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Jraef

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San Francisco Bay Area, CA, USA
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Electrical Engineer
The panel rating has nothing to do with the size of the service, other than as an upper limit. In other words a 125A rated panel cannot be used on a 200A service, but most mfrs offer 60A, 125A, then 200A or 225A panel ratings. They rarely offer a separate panel rated 100A and then 125A, it makes no sense economically. As previously suggested if you can't get an answer from the PoCo, then base it on the conductor size from the meter.

Split bus panels used to be very common when I apprenticed in California too, but I don't see them used much any more either (although I haven't done resi work in 30 years). I think it's too confusing for the average Joe homeowner and can be very dangerous for the DIY crowd. They turn off the breaker labeled "main" and don't know to check everything twice...
 

Little Bill

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Tennessee NEC:2017
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From the OP's description the MLO bus ends at the bottom of the top (L & R) two pole breakers. The second set of bus (split bus) begins at the third slot on both sides and continues down.

Ok, got it! sometimes you have to drill through deeper to get in my little brain!:grin:
 

K8MHZ

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Michigan. It's a beautiful peninsula, I've looked
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Electrician
I have a breaker panel set up the same way, but it uses 60's on each side.

I am interested in this thread because when I went to change insurance companies they wanted to know if I had at least a 100 amp service. I always considered the size of the main to be the size of the service. If I was wrong, then I have a 120 amp service, not a 60, correct?
 

Dennis Alwon

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Location
Chapel Hill, NC
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Retired Electrical Contractor
I have a breaker panel set up the same way, but it uses 60's on each side.

I am interested in this thread because when I went to change insurance companies they wanted to know if I had at least a 100 amp service. I always considered the size of the main to be the size of the service. If I was wrong, then I have a 120 amp service, not a 60, correct?

The individual breakers have nothing to do with it. The ampacity of the service conductors conductors are the telling sign. With 2 - 60 amp breakers I would guess it is 100 amp but it could be a 125 amp service.
 
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