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Wiring an ADU

9825 Views 14 Replies 9 Participants Last post by  Cow
First time wiring an ADU. Here's what I want to do. Hoping someone can check my plan.

FIRST PROBLEM

1) Utility comes in at main house. ADU is currently a detached garage
2) Installing a new meter and mast on the main home per utility requirement for 125 amp
3) Have to run the power from the meter through the main homes basement and then underground to the ADU. So since this is going to be longer than 15 feet I need to have a disconnect. Well the disconnects I can find are rated 200 amp so I would have to get a fused disco and put in 125 amp fuses. PROBLEM these things are friggin expensive. What I would like to do is install a 125 amp main breaker panel at the main house. Then put in a 125 amp breaker with hold down screw. Then run power out to the ADU to another 125 amp main breaker panel. This would cost half as much.

SECOND PROBLEM

1) How to run my grounding?
2) I know the neutrals would need to float at the ADU
3) I have my UFER ground in place already
4) Install two ground rods
5) What else would I need to do for grounding.
6) water is all pex in the ADU
7) Do I need to bring water bonding from the main house to the ADU?

Sorry for the Book:thumbsup:
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You bond your noodle and ground at first point of overcurrent. So your grounding system would be built there, and the panel in the ADU would be a sub...and I would use a MLO panel in the garage. Why don't you put a 125 breaker in the existing panel. .and place a private meter beside the main panel and treat the second panel as a sub? Which is the case any way?
Did I get Cleetised?
 

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Well I love the sarcasm with electrician talk but sometimes my radars off....

ADU=Accessory Dwelling Unit

But of course if you guys could of helped you would have known the meaning...Congrats on knowing everything, your mom must be so proud:)
You're the one asking the questions!:whistling2:

If you have a Uffer, you don't need the ground rods.

And I never heard of ADU either!
In-Law Apartment :thumbsup:
Guest House :thumbsup:
MIL apartment :thumbsup:

But no ADU here.:no:
 

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Yep I'm asking questions. Is that allowed here?
Thanks for the UFER cancelling out the ground rods. I was not aware of that.
Type ADU into the google bar and see what comes up first.

I tried to get the AHJ (authority having jurisdiction) answer these but was not getting clear answers.....
I was replying to this comment:

But of course if you guys could of helped you would have known the meaning...Congrats on knowing everything, your mom must be so proud:)
I would just put a MLO outside panel and put in a 125A breaker. I think someone already said that. Or put in a 100A MB panel and feed from a 125A breaker to your addition.
You can sometimes get a MB panel cheaper than a MLO.
 

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Well I love the sarcasm with electrician talk but sometimes my radars off....

ADU=Accessory Dwelling Unit

But of course if you guys could of helped you would have known the meaning...Congrats on knowing everything, your mom must be so proud:)
Using a non electrical acronym and then ridiculing the electricians you're asking questions of when they're unfamiliar with it is textbook douchebaggery. I'll leave your mom out of it for now
 

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Before you go through the trouble, you might wanna check with local ordinances... they won't allow 2 services on the same plot of land in some areas around here... 1 guy built a new house and wanted to rent his old one... we ended up building a 600a service and sub feeding the old house

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Using a non electrical acronym and then ridiculing the electricians you're asking questions of when they're unfamiliar with it is textbook douchebaggery. I'll leave your mom out of it for now
Yeah, he seems so smart he shouldn't have any problem figuring it out on his own. I mean come on, we didn't even know what an ADU was, how the heck are we going to know how to wire one?!?!

Since it sounds REALLY complicated, he would probably be better off without me guessing how to do it.....
 
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