How would you have handled this?

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Chamuit

Chamuit

Grumpy Old Man
Location
Texas
Occupation
Electrician
I run into situations like this occasionally.

Went to a machine shop to look at an existing electrical situation with an old, old, old Air Con. It is (was) being fed by a 3P 100A breaker. Couldn't read the MCA because it is so old.

Panelboard feeding this is a SqD QO rated 200A and being fed by a 225A breaker at the 1300A main section. Told the A/C manufacturer rep that the new unit should stick to 100A maybe 125A. He comes back with a MCA of 165A (3 phase.) So, I told them that they would have to get an engineer to give his blessings since there is considerable amount of other equipment connected to this panel, including this load. They were a little put out that I wouldn't sprinkle holy water on it and say they were good.

I feel I am right because I am not going to take the risk. Heck , I don't want to take that risk. Just want to hear some reassurance or critique from the engineers (and any one else, too) along with some pointers or ideas as to why an EE would be a good person to consult with situations like this.

Thanks!
 
Is there room in the MDP to put a breaker for the new a/c instead of in the panel it's in presently? Sounds like you're going to be pulling new conductors anyhow.
 
No. The MDP is maxed out in breaker space. Besides, running a new circuit from the Main Section would be a nightmare. They basically have 5 buildings that have been "tied" together over the years. (Roof lines don't match, walls are set forwardd, set back, so on and so forth.)

I think changing the panelboard out and pulling new feeders would be simpler. There is a 4" GRC running from the MDP to a Pull box right below the existing Panel.

Forgot to mention they want it done cheap.

Chaps my hide when people scab on and band-aid electrical work for decades upon decades then don't wan to pay the piper when it comes to to finally do it.
 
Chamuit said:
Forgot to mention they want it done cheap.
Click to expand...
Time to run and don't look back! They will want you to cut other corners and violate the Code wherever you can to just "get by and make it work." :mad:
 
Actually

Actually

I was wondering what kind of verbage you would use to explain that a job would require some actual Engineering. Even smart-alec remarks.
 
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