Main Disconnect?

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wrobotronic

wrobotronic

Senior Member
Location
Colorado
Hi All,
I read a lot of your posts but first time posting myself. I have a customer whose main panel is located on his garage. He wants me to add a 200A "sub panel" in his house. The panel he insists I use is an MLO. I have tried to explain that he needs a main breaker or disconnect per 230.70. He is not understanding. Is there another code section I can reference to make this clear to him? or is it possible that I am wrong and an MLO panel is ok? The house and garage are separate structures and the feed from garage to house is about 75ft.
Thanks everyone.
 
I suppose I should rephrase. My customer has an EE friend who claims to have designed at least 50 systems with this setup, this year alone. I told him his friend was incorrect and to call the AHJ to confirm if he would like. The EE basically questioned my status as a master and called me an idiot. I think it will be in my best interest to chalk this job up as a loss and move on. He cannot provide a reference to me either, but I provided him with 230.70.
 
wrobotronic said:
I suppose I should rephrase. My customer has an EE friend who claims to have designed at least 50 systems with this setup, this year alone. I told him his friend was incorrect and to call the AHJ to confirm if he would like. The EE basically questioned my status as a master and called me an idiot. I think it will be in my best interest to chalk this job up as a loss and move on. He cannot provide a reference to me either, but I provided him with 230.70.
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What's powering the house now? You need a main on the house somewhere.
 
ActionDave said:
What's powering the house now? You need a main on the house somewhere.
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Well, you need a service disconnect on the house somewhere.
That could be either in the form of a main or of up to six grouped smaller disconnects.

PS: Any reason you can see that the six could not be a mix of breakers and fused disconnect switches?
 
It sounds like a feeder, article 230 would not apply.

The rules would be found in part II of 225. More or less the same but still.
 
What is the big problem on using a panel with a Main breaker.
You are going to loose a job over such a thing.
 
iwire said:
It sounds like a feeder, article 230 would not apply.

The rules would be found in part II of 225. More or less the same but still.
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agree. If you are going to try to win by quoting NEC, take a look at Art 225 Section II.
As iwire states, basically the same rules as Arr 230 but don't want you to loose face by quoting the wrong Article.
 
The separate building needs to have the ability to turn off all power (at/within the building) with six moves or less of the hand.

If you can wire this house with only six circuits (multiwire circuits would be permitted for the sake of determining number of handles) then you don't need a main breaker panel;)
 
Exterior Disconnect

Exterior Disconnect

Explaining to him where he went wrong might (or might not) help. You know the following, and he has probably known it in the past, so maybe triggering his brain will help. IF you provide a main disconnect on the exterior of the house, THEN the panel can be MLO. Instead of telling him he can't do it, if you ask where he wants the main disconnect to go, it might make life a lot easier.

If the garage is an attached garage then it isn't a separate building and the engineer would have been correct.

As an engineer, I welcome questions and get a bit frustrated when "told". If you can figure out how to make everything a question, it might go over better.

"Doesn't this installation fall under NEC 225? How are you meeting section______? " and so forth.

Could be he was expecting a disconnect all along and will say, "Well, duh!" or something. (Or not. I acknowledge that there are arrogant engineers that end up paying through the nose eventually for being arrogant and wrong. I personally thank contractors profusely for asking. If they don't ask, I might be wrong, or more likely, they may do something in a way I specifically didn't want for a reason that isn't obvious. I love those questions.)
 
That is exactly the approach I used today. While, for some reason, I didn't ask him, he still disagrees, the AHJ weighed in and explained that it is required. While I don't practice, I went to U of Minnesota for EE, and thought I understood EEs. But the question approach was a great call and will put that method into action moving fwd. Thank you all again for helping. This place is a great resource.
 
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