150 or 300A service?

**Ken Amelin** · 10-03-2009, 03:45 AM

I inspected a house that has 2-150 amp "service" panels. Each panel has a main breaker rated at 150A. The panels are fed underground (independently) from a meter box on a pedestal outside near road electric pole. There are no main disconnects at meter box.

I see this a lot, but I always have a few questions about it. Maybe you can help. (Uhmm - I'm sure you can help)

1. Are both these panels considered - main service equipment?
2. Can you have two main disconnects (service entrances) for a home? (I thought you needed one main shut off for safety?)
3. How would you rate the service size - 300A service or 2-150A services?

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**Rick Cantrell** · 10-03-2009, 04:43 AM

Ken
I give it a try. Some of the more knowledgeable people will correct me if I'm wrong.

" 1. Are both these panels considered - main service equipment?"
Yes. Both panels together make up the service equipment.

"2. Can you have two main disconnects (service entrances) for a home?"
Yes you can have "two main disconnects", but only 1 service entrance allowed per home.

" (I thought you needed one main shut off for safety?)"
You can have as many as 6 disconnects, and they can be in multiple panel boxes.

"3. How would you rate the service size - 300A service or 2-150A services?"
300

**Ken Amelin** · 10-03-2009, 10:20 AM

Rick,

Thanks for the reply, but now I have another question.

You mentioned you could only have one service entrance, but can have two panels that are service equipment.

What is considered a service entrance? The house has two separate panels fed separately from outside. To be more specific - three conductors come through a sleeve in the concrete wall to one panel and three conductors come through a separate second sleeve in the concrete wall to the second panel.

Is this not two service entrances?

**Rick Cantrell** · 10-03-2009, 11:56 AM

You (and I) will need to wait for someone else to answer that.

**Jerry Peck** · 10-03-2009, 12:24 PM

Originally Posted by Ken Amelin

1. Are both these panels considered - main service equipment?

Yes, both panels are "service equipment".

2. Can you have two main disconnects (service entrances) for a home? (I thought you needed one main shut off for safety?)

Yes, you can have up to 6, but all 6 must be grouped together and labeled.

3. How would you rate the service size - 300A service or 2-150A services?

I always rated it as two 150 amp main disconnects with two 150 amp panels.

**Jim Luttrall** · 10-03-2009, 12:32 PM

Originally Posted by Ken Amelin

Rick,

Thanks for the reply, but now I have another question.

You mentioned you could only have one service entrance, but can have two panels that are service equipment.

What is considered a service entrance? The house has two separate panels fed separately from outside. To be more specific - three conductors come through a sleeve in the concrete wall to one panel and three conductors come through a separate second sleeve in the concrete wall to the second panel.

Is this not two service entrances?

One meter = One service

**Jerry Peck** · 10-03-2009, 12:40 PM

Originally Posted by Jim Luttrall

One meter = One service

Not always.

You can have one service with multiple meters on it.

One service drop or one underground service lateral would make one service.

**Ken Amelin** · 10-04-2009, 07:16 AM

Originally Posted by Jerry Peck

Quote:

Originally Posted by Ken Amelin

1. Are both these panels considered - main service equipment?

Yes, both panels are "service equipment".

Quote:

2. Can you have two main disconnects (service entrances) for a home? (I thought you needed one main shut off for safety?)

Yes, you can have up to 6, but all 6 must be grouped together and labeled.

What does "all must be grouped together" mean? Like by arms reach? physically joined? Wired together?

Quote:

Originally Posted by Jim Luttrall

One meter = One service

Not always.

You can have one service with multiple meters on it.

One service drop or one underground service lateral would make one service.

Does this mean that the six conductors running from the outside meter to each panel is the "service lateral"? Do all conductors have to be in the same trench? Any distance requirements for a service lateral of multiple conductors to multiple service entrance panels?

**Jerry Peck** · 10-04-2009, 09:21 AM

Originally Posted by Ken Amelin

What does "all must be grouped together" mean? Like by arms reach? physically joined? Wired together?

It means that if you are standing there at one of them you should be able to access the others there too.

Not necessarily "physically joined" but not one here, one 50 feet down the wall, not another one another 50 feet down the wall. It is a subjective and vague term, but when you see an installation which is not grouped together, you will recognize it.

Does this mean that the six conductors running from the outside meter to each panel is the "service lateral"?

The conductors running from the meter to the main service disconnects are "service entrance conductors".

Do all conductors have to be in the same trench?

No requirement for that, but why dig multiple trenches when the service entrance conductors all need to go the the same location on the wall?

Each set of service entrance conductors needs to be grouped together in their own raceway or cable.

Also, if you are running 6 sets of service entrance conductors from a single meter you would need terminals designed for that - thus is it more likely you would run 1 set of service entrance conductors to a wire gutter where it splits up into the separate service entrance to each service disconnect.

Any distance requirements for a service lateral of multiple conductors to multiple service entrance panels?

That would be a voltage drop calculation.