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Odd electrical installation


Tim Maxwell
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Today I had a house built in 2006. The main electrical shut off was in the basement main panel.

There is a sub panel installed in the upstair bonus room. The shut off for the sub panel is at the exterior near the meter.

It is a new one on me. Seems very odd that it would be set up so that you'd have to shut off two breakers to be able to shut off all the electrical for the house.

I went over it a couple of times while I was there and could not see where the SEC came into the main panel from, like from the meter housing or off of the 100 amp sub panel breaker out side.

Any advice on this? I'm planning on referring an electrician but really want to understand what has been done here.

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What you probably have there is two individual service panels, not a main and a sub. Each one is indivdually fed from the meter.

The reason the disconnect for the second panel is outside is because the SEC cannot run on the interior longer that 5' without a disconnect. So, they put the disconnect outside near the meter. This way the conductor can run at lengths longer than 5' through the interior of the house to the second panel.

I probably mangled this explanation. I invite anyone to clean it up.

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All service disconnects for a single dwelling are required to be grouped together and must not exceed more than six in number. In other words, a fireman must be able to remove all electrical power to the house in case of a fire with no more than six movements of his hand at a single location.

The question is how are each of the two panels receiving power. From your description, my guess is that a second set of taps on the load side of the meter is present. If my guess is correct, violations are likely represented by the second set of taps and by the fact that the two service disconnects are not consolidated in one location.

Just my opinion, is all.

Marc

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It sounds like two service disconnects fed from one meter.

There would be no need to use the bypass lever to disconnect the power. Just throw the two breakers in the disconnects. Besides, at least on the meter sockets I have seen the bypass is located under the meter cover and is only accessible with the socket open.

To Tim, a main breaker may be in the basement panel, but it is not the service disconnect. As shown in your pic the service disconnect is outside at the meter. The breaker inside the basement panel is redundant.

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Tim

From what you describe you have 2 peices of service equipment.

You say there is a panel that has a main disconnect that shuts off the major part of the house. Then you also have a panel on the second floor in the bonus room that is disconnected by the 100 amp exterior breaker.

The 100 amp disconnect in you picture is for the second floor bonus room panel correct ?

You say you could not see the SEC for the lower level panel correct ?

Most likely it is a nipple from the back of the meter enclosure to the back of the panel enclosure. Did you take the cover off the panels ?

If you have 2 "main disconnects" ( one is the 100 exterior & the other is the main breaker in the panel) then you have a violation of article 230.72 in the National Electrical Code (NEC) These disconnects must be grouped together!

The 100 amp exterior breaker is fed from the meter as well as the interior main breaker, correct ? This being said . This is the service disconnecting means for the 2nd floor panel. Anything after this disconnect to the 2nd floor is a feeder thus the second floor panel is a sub panel and must be wired as such. All grounds and neutrals must be isolated from each other.

Another thing to look at is the label on the exterior disconnect. Seeing how it is used for service equipment it MUST be labeled as such.

It should state somewhere " Suitable for Use as Service Equipment".

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What you probably have there is two individual service panels, not a main and a sub. Each one is indivdually fed from the meter.

The reason the disconnect for the second panel is outside is because the SEC cannot run on the interior longer that 5' without a disconnect. So, they put the disconnect outside near the meter. This way the conductor can run at lengths longer than 5' through the interior of the house to the second panel.

I probably mangled this explanation. I invite anyone to clean it up.

Did a good job there John-

The 2nd floor panel is a sub panel. It is a sub panel off the 100 amp disconnect on the exterior.

The "service equipment" is the 100 amp exterior disconnect and the interior main breaker panel.

That 5' is that a local admendment as the NEC states "nearest the point of entrance" which leaves it up to the AHJ to decide. Most want it as short as possible.

There is aviolation of NEC 230.72 Grouping of the main disconnects.

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