Running wire for 100a sub panel in shop

[62stepside]

62stepside you maybe confused on the wire sizes and breaker sizes. If the continuous feeder from the source panel to the garage panel is made up of #2/0 and #2 spliced together the source panel breaker feeding the wire to the garage is to be no larger than 90A because of the #2. The subpanel in the garage can have a 100A main breaker because it's a disconnect only and is not the primary breaker protecting the feeder.

I understand now.

I really really appreciate yours and everybody's help! Thank you!

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[pattenp]

My electrician said the max breaker size, in my 100 amp main panel, could only be 60 amp to feed my subpanel in the detached garage?

The only reason that would be is the panel's listing label stated that 60A was the max breaker size for branch circuits.

 

[mike93lx]

My electrician said the max breaker size, in my 100 amp main panel, could only be 60 amp to feed my subpanel in the detached garage?

If this is a question, i would recommend starting your own post with details. Otherwise AFAIK, your downstream breaker sizing is independent of upstream breakers. Installing a 200a sub on 100a service would just result in a tripped main if your sub exceeded 100a draw

 

[laser3kw]

If this is a question, i would recommend starting your own post with details. Otherwise AFAIK, your downstream breaker sizing is independent of upstream breakers. Installing a 200a sub on 100a service would just result in a tripped main if your sub exceeded 100a draw

not a question. I thought its pertinent to the situation as my install similar to the OP's. But, my install has a 100 amp service therefore the 60 amp feed to a subpanel is maximum permitted
I guess I must assume the main feeding the OP's sub is a 200, therefore, the 90 amp subpanel feed is permitted.

 

[alfredeneuman]

It could be that the electrician that 60A max came to that decision by adding the circuits required by Code, and the sq.feet of dwelling @ 3va per sq. ft. which is all detailed in Article 220 of the NEC.

 

[wyliesdiesels]

not a question. I thought its pertinent to the situation as my install similar to the OP's. But, my install has a 100 amp service therefore the 60 amp feed to a subpanel is maximum permitted
I guess I must assume the main feeding the OP's sub is a 200, therefore, the 90 amp subpanel feed is permitted.

The devil is in the details.

In general, there is no prohibition on installing a 100a feeder on a 100a service.

Your situation must have a specific reason why you are limited to 60a...

 

[laser3kw]

The devil is in the details.

In general, there is no prohibition on installing a 100a feeder on a 100a service.

Your situation must have a specific reason why you are limited to 60a...

I don't know for sure. I had a licensed electrician do mine. He stated that the sub panel feed (breaker) could not be more than two-thirds the main (amperage) or something like that. May be a local code thing. The install was inspected and signed off on by the county so all is good.
I wanted 100 amp in the garage, but he said 60 would be just fine. But, the wiring going to the garage was sized for 100 amp - just in case!
I haven't had any problems with 60 amp, I just make sure I don't allow the air compressor to run if I am welding ( very infrequently)

 

[62stepside]

Ok, small update I ordered some 1/0 1/0 1/0 2 SER cable to run from the underground attachment through the garage and under the house. I'm going to get a 8" or 12" junction box to connect the wires together in using Polaris connectors. Next step is to run the 4th ground wire to the shop and then work on the main panel box wiring.

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[pattenp]

Ok, small update I ordered some 1/0 1/0 1/0 2 SER cable to run from the underground attachment through the garage and under the house. I'm going to get a 8" or 12" junction box to connect the wires together in using Polaris connectors. Next step is to run the 4th ground wire to the shop and then work on the main panel box wiring.

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Why did you get #1/0 when #1 was enough? Not that its hurts but is just heaver wire to work with. I suggest the 12" box.

 

[62stepside]

Sorry he just texted me hes getting me #2 ser.

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[pattenp]

That makes better sense since you are connecting it to #2 URD. The box size is to be 6 times the largest diameter conduit entering the box. So if you have 2" conduit the box should be 12". If you can reduce the conduit size to 1.25" entering the box then you can use a 8" box.

 

[62stepside]

Ok. Thank you. I'll probably stick with the 12" just to make it easier.

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[62stepside]

I have everything ran. The 2224 ser cable up the wall through rafters back down the wall and then ran under the house.

For my grounding in the shop (all steel building (enclosed carport)) I need size 8 copper wire or 6 aluminum. I run that wire from the ground bar in the panel to the 2 ground rods correct? Or do I need to run it from the panel to the steel framing then from the steel framing to the ground rods?

Thanks for the advice

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[wyliesdiesels]

Run solid #6 cu from the ground bar in the panel to the 2 rods and also the building steel.

Also, did you isolate the neutral bar?

 

[62stepside]

I did not isolate neutral bar what do I need to do.



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[alfredeneuman]

Some meter enclosures, meter/main, and combination services come with permanently bonded neutrals.
Others already have isolated neutrals.
A neutral bonding screw or strap is supplied with the panel (it should be tagged or marked as such).
Just don't install the screw (or connect the strap).

 

[62stepside]

Is this coreect?

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[62stepside]

Looks like nuetral bar screw is not installed.

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[wyliesdiesels]

Actually it IS installed.

Its clearly labeled on the black plastic.

See the green screw?

You can see it in pics 1 and 3

 

[62stepside]

Ah ok sorry it says ground strap where the green screw is. The other without the screw says nuetral strap.

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[dscheidt]

Ah ok sorry it says ground strap where the green screw is. The other without the screw says nuetral strap.

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That green screw bonds the bus bar to the case. You must remove it in a subpanel.

 

[62stepside]

That green screw bonds the bus bar to the case. You must remove it in a subpanel.

Thank you!

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[wyliesdiesels]

Ah ok sorry it says ground strap where the green screw is. The other without the screw says nuetral strap.

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Are the bars connected to each other?

 

[62stepside]

Ok. I got an electrician to come out and wire the shop portion so far. Inspector is coming 6/4. Electrician told me that the mc cable between the frame and metal siding might not be "supported" according to the inspector. Since it's not supported every 18".

Anyone have any ideas since my frame supports are 5 feet wide from each other?

I thought about getting 2x3's and mounting them so they pretty cover the metal siding groove that they are running in.


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