Motor installation:

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Tony S

Tony S

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Resting under the Major Oak UK
I know you all follow NEC religiously but can anyone find a good reason for this abortion. Either NEC or NEMA codes will do.

It was found by one of our commissioning engineers somewhere in the US.

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My main concern is the lack of a terminal block in a 75HP motor. It doesn’t comply to NEMA ICS 4 as I see it.

Our guy is going to have to guarantee this installation, he won’t as it stands now.
He’s dealing with the local issues but I thought I’d ask for your electricians views on this small section of the installation.

I daren’t repeat the views of UK industrial electricians.
 
Tony S said:
My main concern is the lack of a terminal block in a 75HP motor. It doesn’t comply to NEMA ICS 4 as I see it.
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The NEMA Standard for motors is MG 1 and ICS 4 is not a referenced document nor are any UL Standards.

The NEMA Motors and Generator Section pretty much march to their own drummer.
 
Tony S said:
I know you all follow NEC religiously but can anyone find a good reason for this abortion.
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Tony, just because something is done differently than you are used to does not make it wrong or an 'abortion'.

I see nothing unusual, unsafe or in violtion of our codes.
 
I can't tell from here the size of the wires, if sleeves for fine stranded wires were used in the motor connections, if the j-box goes to the 75 hp motor, if the raceway leaving the motor is flexible non metallic, EMT, rigid or what.

Tell us us what your concerns are. Did it pass a local area inspection?
 
As Bob said I don't see a problem either. Looks like a pretty standard USA instillation.
 
ptonsparky said:
Tell us us what your concerns are. Did it pass a local area inspection?
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It hasn’t got to that stage yet, an ongoing project.

But as it is designed and guaranteed by a UK company the specification is an amalgam of NEC, BS7671 and EAWA therefore a very high standard is required. The guy on site won’t accept anything not in the specification.

I doubt a final inspection will fail but it won’t get passed by our man. He’s the one to sign the “hand over”

Is there a problem with “over designing” something when a $XM guarantee is involved?
 
Tony S said:
It hasn’t got to that stage yet, an ongoing project.

But as it is designed and guaranteed by a UK company the specification is an amalgam of NEC, BS7671 and EAWA therefore a very high standard is required. The guy on site won’t accept anything not in the specification.

I doubt a final inspection will fail but it won’t get passed by our man. He’s the one to sign the “hand over”

Is there a problem with “over designing” something when a $XM guarantee is involved?
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It will pass NEC, assuming the conductors are large enough. From what I have seen I have to question whether they are large enough for a 75 HP motor though. Unless the conductors shown in the 4-11/16 box are not for this motor, the proper minimum size conductors for this motor shouldn't fit in the blue connectors in that box, nor should you even be able to pull them through a box that small very easily.

Design specifications can exceed the NEC requirements, NEC is just minimum safety requirements, going beyond those requirements may have advantages may not.

NEC generally doesn't care about cost either.
 
conductor

conductor

The wire does appear to be one size too small. I can read 2 AWG in the picture, which should be good for 115 amps. A continuous duty 75 HP motor at 96 amps needs an ampacity at 125% of that, or 120 amps.
There could be extenuating circumstance that rationalize it, but at first glance it looks too small.
 
[QUayanees;1670897]The wire does appear to be one size too small. I can read 2 AWG in the picture, which should be good for 115 amps. A continuous duty 75 HP motor at 96 amps needs an ampacity at 125% of that, or 120 amps.
There could be extenuating circumstance that rationalize it, but at first glance it looks too small.[/QUOTE]

The 2 is a motor lead, if my bifocals havent failed me again.
 
Tony S said:
It hasn’t got to that stage yet, an ongoing project.

But as it is designed and guaranteed by a UK company the specification is an amalgam of NEC, BS7671 and EAWA therefore a very high standard is required. The guy on site won’t accept anything not in the specification.

I doubt a final inspection will fail but it won’t get passed by our man. He’s the one to sign the “hand over”

Is there a problem with “over designing” something when a $XM guarantee is involved?
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If you are paying, you get to set any standards you want. Above or equal to NEC. Everyone needs to know and understand your specs. Somewhere, someone surley had to submit spec sheets for approval, right?
 
I can't read any size on the conductors coming in. The motor leads themselves clearly say 2 AWG.

For a 75HP 480V motor the minimum conductor size would be #1.

I don't see anything really "wrong" with anything else, although the yellow tape seems odd on the connectors.
 
petersonra said:
... although the yellow tape seems odd on the connectors.
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My guess is to help retain the caps on the set screw ports. Those particular ones seem to fall out.

One other possible code issue is those connectors possibly are not listed for use with fine stranded conductors, though we don't know exactly what is being used there. The motor leads are most likely fine stranded though.
 
Tony, I apologize for my ignorance:dunce::ashamed1:, but still curious. Under BS7671, what would be in violation?


My concern here is the wire nuts look like they were put on with channel lock pliers, and as stated the wire might be to small per NEC though I doubt it would actually be dangerous in reality.
 
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