RV Garage

[James S.]

Yesterday I went out to look a house that is planning on building a stand alone RV garage. He wants to put a 100 amp sub panel inside the garage and told me his 'electrician friend in Alaska' said that he will definitely need a disconnect outside the garage. My initial thoughts are that there is a disconnect in the main panel along with the 100 amp breaker in the main that should serve as a disconnect. Or am I missing something? Is there a code requiring a disconnect on the outside of the building within a certain distance? Kind of like with pools.

The second question is with the ground. I was taught that there is only one ground. And that is at the main panel but seems like I have read somewhere that detached structures require there own ground (ufer). Is that right and where is that in the code book?

Thanks in advance guys.

 

[kwired]

Yesterday I went out to look a house that is planning on building a stand alone RV garage. He wants to put a 100 amp sub panel inside the garage and told me his 'electrician friend in Alaska' said that he will definitely need a disconnect outside the garage. My initial thoughts are that there is a disconnect in the main panel along with the 100 amp breaker in the main that should serve as a disconnect. Or am I missing something? Is there a code requiring a disconnect on the outside of the building within a certain distance? Kind of like with pools.

The second question is with the ground. I was taught that there is only one ground. And that is at the main panel but seems like I have read somewhere that detached structures require there own ground (ufer). Is that right and where is that in the code book?

Thanks in advance guys.

NEC would only require the disconnect to be either outside or "inside nearest the point of entry." The NEC does not specify just how close to the point of entry it must be, and some local AHJ's have made amendments that do specify distances, or there may be some that would say it must be outside. Chances are your AHJ uses the same rule they have adopted for the same situation regarding the service disconnect. See 225.32

All separate buildings or structures require a grounding electrode system, you connect it to the equipment grounding conductor though instead of the grounded conductor (neutral) exception being existing older installs where it used to be permitted to not run a separate equipment grounding conductor. Exception being a structure served by a single branch circuit. See 250.32

 

[qcroanoke]

NEC would only require the disconnect to be either outside or "inside nearest the point of entry." The NEC does not specify just how close to the point of entry it must be, and some local AHJ's have made amendments that do specify distances, or there may be some that would say it must be outside. Chances are your AHJ uses the same rule they have adopted for the same situation regarding the service disconnect. See 225.32

All separate buildings or structures require a grounding electrode system, you connect it to the equipment grounding conductor though instead of the grounded conductor (neutral) exception being existing older installs where it used to be permitted to not run a separate equipment grounding conductor. Exception being a structure served by a single branch circuit. See 250.32

Agreed.

 

[James S.]

NEC would only require the disconnect to be either outside or "inside nearest the point of entry." The NEC does not specify just how close to the point of entry it must be, and some local AHJ's have made amendments that do specify distances, or there may be some that would say it must be outside. Chances are your AHJ uses the same rule they have adopted for the same situation regarding the service disconnect. See 225.32

All separate buildings or structures require a grounding electrode system, you connect it to the equipment grounding conductor though instead of the grounded conductor (neutral) exception being existing older installs where it used to be permitted to not run a separate equipment grounding conductor. Exception being a structure served by a single branch circuit. See 250.32

Thanks guys. So the breaker in the main panel (which is outside but on the other side of the house) shouldn't be a problem unless the AHJ requires something else. I will have to check for that.

Thanks again guys.

 

[suemarkp]

The garage disconnect needs to be at the garage (either outside or immediately inside or however far they let you go in your area). The feeder breaker at the house doesn't count as the RV building disconnect on residential property unless maybe it was just a few feet away from the RV garage.

 

[iceworm]

...his 'electrician friend in Alaska' said that he will definitely need a disconnect outside the garage. ...

Just so we are clear - It wasn't me. I only do DIY work in a few isolated locations in Texas.:angel:

ice

 

[kwired]

The garage disconnect needs to be at the garage (either outside or immediately inside or however far they let you go in your area). The feeder breaker at the house doesn't count as the RV building disconnect on residential property unless maybe it was just a few feet away from the RV garage.

Correct, unless the garage would happen to be attached to the house, then a main breaker is not needed, the feeder breaker in the house panel is fine if it doesn't exceed the panel rating and appropriate sized conductors are run, and a grounding electrode is not needed either at the garage. I assume from the OP that this is a separate structure though.

One other thing though is if there is six or less breakers in the panel it would not need a main breaker in the panel.

 

[James S.]

The garage disconnect needs to be at the garage (either outside or immediately inside or however far they let you go in your area). The feeder breaker at the house doesn't count as the RV building disconnect on residential property unless maybe it was just a few feet away from the RV garage.

Thanks, you don't happen to have the article number handy? I don't like not knowing stuff and want to read up on it.

 

[James S.]

Correct, unless the garage would happen to be attached to the house, then a main breaker is not needed, the feeder breaker in the house panel is fine if it doesn't exceed the panel rating and appropriate sized conductors are run, and a grounding electrode is not needed either at the garage. I assume from the OP that this is a separate structure though.

One other thing though is if there is six or less breakers in the panel it would not need a main breaker in the panel.

Totally separate structure.

 

[kwired]

Thanks, you don't happen to have the article number handy? I don't like not knowing stuff and want to read up on it.

Read through art 225 particularly part II. Most of what is in that part applies to your installation.

 

[James S.]

Read through art 225 particularly part II. Most of what is in that part applies to your installation.

Thank you.