Sub panel to another Sub panel

[DWhitt]

I currently have a detached garage app 200 ft from my house and has a 100 amp panel and 90 amp breaker in main panel. My question is I am getting ready to build another detached garage app 60 ft from existing garage and would like to install a sub panel in the new building and feed it from the existing sub panel in the existing detached garage. I don't plan on having anything needing 240. Just having lights and outlets for power tools and air compressors. There will not be any heavy use in both garages at the same time.... Question is can I have a sub panel supplying juice to another sub panel?

 

[Bert_]

You could have 10 sub panels. The only thing that matters is the amount of load.

 

[wyliesdiesels]

I currently have a detached garage app 200 ft from my house and has a 100 amp panel and 90 amp breaker in main panel. My question is I am getting ready to build another detached garage app 60 ft from existing garage and would like to install a sub panel in the new building and feed it from the existing sub panel in the existing detached garage. I don't plan on having anything needing 240. Just having lights and outlets for power tools and air compressors. There will not be any heavy use in both garages at the same time.... Question is can I have a sub panel supplying juice to another sub panel?

yeah

 

[ddurrett896]

Question is can I have a sub panel supplying juice to another sub panel?

Yes. I have a 200 amp panel feeding an 100 amp sub that feeds a 60amp sub

 

[dcg9381]

You could have 10 sub panels. The only thing that matters is the amount of load.

Well, not that many in series.
My shop has 1 main and 4 sub panels currently. Back when wire was "cheap" (in terms of keeping it simple and reducing labor) - it made a lot more sense to bring 60A+ of power over to the other side of the building versus running a bunch of individual wires from the main... My typical sub-panel install is a panel with a GFCI 20A, a 30A, and a 50A 240v. Saves a lot of labor.

 

[Terry D]

Well, not that many in series.
My shop has 1 main and 4 sub panels currently. Back when wire was "cheap" (in terms of keeping it simple and reducing labor) - it made a lot more sense to bring 60A+ of power over to the other side of the building versus running a bunch of individual wires from the main... My typical sub-panel install is a panel with a GFCI 20A, a 30A, and a 50A 240v. Saves a lot of labor.

There is no limit on how many subs you can have. You can have as many of sub panels you want out of your main panel or feed a sub off a sub off a sub and so on. As said its all about the total combined load your putting on the breaker(s) feed those subs and also the main breaker of the service.

 

[theoldwizard1]

The "size" of a sub panel (number of circuits and a "main" disconnect) and the number of sub panels only depends on the size of the wire from the first panel and the breaker protecting that wire. Everything else downstream really does not matter much.

 

[DWhitt]

Thanks everyone for the feedback.... This is exactly what I was looking for.

 

[dcg9381]

There is no limit on how many subs you can have. You can have as many of sub panels you want out of your main panel or feed a sub off a sub off a sub and so on. As said its all about the total combined load your putting on the breaker(s) feed those subs and also the main breaker of the service.

I was under the impression that there was a limit to the number of "disconnects" that you could have upstream of service, which inherently limits the number of down-stream sub panels. It looks like this has somewhat changed in 2020, so I stand to be re-educated:

230.71 Maximum Number of Disconnects.

Three different service configurations. One is a code violation.

www.electricallicenserenewal.com

 

[pbon]

My house has a 400A main with one sub in the house and 3 subs in the garage.

 

[Bert_]

I was under the impression that there was a limit to the number of "disconnects" that you could have upstream of service, which inherently limits the number of down-stream sub panels. It looks like this has somewhat changed in 2020, so I stand to be re-educated:

230.71 Maximum Number of Disconnects.

Three different service configurations. One is a code violation.

www.electricallicenserenewal.com

That refers to SERVICE disconnects. A service disconnect is the first over current device after the meter.

A sub panel might have a main breaker for a disconnect, but it's not a SERVICE disconnect.

 

[dcg9381]

That refers to SERVICE disconnects. A service disconnect is the first over current device after the meter.

A sub panel might have a main breaker for a disconnect, but it's not a SERVICE disconnect.

Thanks... With the photo here, I think I get it: https://www.electricallicenserenewa...Courses/graphics/sectionPics/large/qid844.jpg

 

[Terry D]

I was under the impression that there was a limit to the number of "disconnects" that you could have upstream of service, which inherently limits the number of down-stream sub panels. It looks lik

I was under the impression that there was a limit to the number of "disconnects" that you could have upstream of service, which inherently limits the number of down-stream sub panels. It looks like this has somewhat changed in 2020, so I stand to be re-educated:

230.71 Maximum Number of Disconnects.

Three different service configurations. One is a code violation.

www.electricallicenserenewal.com

As long as all power in a building can be turned off in 6 throws. If you have a main breaker in your first panel , that will kill all power in one throw. If you have a sub panel thats feeding a sub panel thats feeding a sub panel and so on, the breaker feeding the first sub will deenergize all subs down stream.

 

[Terry D]

I was under the impression that there was a limit to the number of "disconnects" that you could have upstream of service, which inherently limits the number of down-stream sub panels. It looks like this has somewhat changed in 2020, so I stand to be re-educated:

230.71 Maximum Number of Disconnects.

Three different service configurations. One is a code violation.

www.electricallicenserenewal.com

As long as all power to a building can be shut off in 6 throws. If you have a main breaker(s), you can have up to six. If you dont have a main, example being a old split buss type panel, and you had a sub feeding a sub feeding a sub and so on, It still would only take one throw to kill the subs. You still would have 5 throws left to kill remaining power.

 

[dcg9381]

As long as all power to a building can be shut off in 6 throws. If you have a main breaker(s), you can have up to six. If you dont have a main, example being a old split buss type panel, and you had a sub feeding a sub feeding a sub and so on, It still would only take one throw to kill the subs. You still would have 5 throws left to kill remaining power.

So I've got two main panels in at my property, both 200A. I thought it was a no-no to bring "dual feeds" into the same building. It sounds like I have this wrong and out of a SINGLE main, I could have 90A "shop west" and 90A "shop east" as long as they originate from the same main?

What was actually prohibited (at least before 2020 NEC) would be having a main with a 90A breaker than powers "shop east" and then having another 90A breaker for "shop west" from a separate main panel.

 

[Bert_]

You CAN'T have MULTIPLE feeds to the same building. You CAN have ONE feed with up to (6) disconnects.

Examples,

2 breakers in one building feeding 2 panels in another building = wrong

One meter feeding 2 main breaker panels = OK, they need to be grouped together.

Once you have a main disconnect (or a group of them) you can has as many sub panels as you want.

 

[wyliesdiesels]

So I've got two main panels in at my property, both 200A. I thought it was a no-no to bring "dual feeds" into the same building.

Thats correct. only 1 feed to a building.

It sounds like I have this wrong and out of a SINGLE main, I could have 90A "shop west" and 90A "shop east" as long as they originate from the same main?

As long as the main is IN THE SHOP, then you can do that and it wouldn't be considered 2 feeds to the same building. the feed to the building is in the main, NOT the 2 subpanels.

What was actually prohibited (at least before 2020 NEC) would be having a main with a 90A breaker that powers "shop east" and then having another 90A breaker for "shop west" from a separate main panel.

correct. that would be 2 feeds to the shop from 2 separate buildings.

however, usually there is only ONE main panel per service/meter, unless of course you have a dual lug meter w/ 2 mains off of it.

 

[dcg9381]

however, usually there is usually only ONE main panel per service/meter, unless of course you have a dual lug meter with 2 mains off of it.

Thanks, Wylie. Yes, I've got dual panels coming off a dual lug meter. I appreciate you clearing it up!