Neutrals feeding through disconnect

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Dobie1979

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Grand Rapids, Mi
Hello,
First time poster here.

I've seen some machines being introdiced into my facility being fed by 120VAC.

The hot and the neutral are feeding the main disconnect and both are feeding 30amp fuses. The 120 VAC circuits are just 24 vdc power supplies, PLC and Ethernet switches.
I've tried to look into the 2014 NEC and only thing I could find is if they all open at the same time then it's OK. Some of the crew says they'd never do it that way and I'm not sure.
Looking for additional feedback.

Thanks in advance
 
There are a few cases were the neutral is required to be on a breaker however fuses will not allow both wires to be disconnected. I am not certain if this applies to 24v or not. I am sure someone here will kinow. I just don't have time to check it out now.BTW, welcome to the forum
 
If I understand your question, the fuses in question are installed in the 120v supply circuit. If so, they are in violation of 240.22
 
augie47 said:
If I understand your question, the fuses in question are installed in the 120v supply circuit. If so, they are in violation of 240.22
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agreed.

having said that, I would make sure this is really a grounded system. people do all kinds of screwy things like feeding control panels from a xmfr with an ungrounded secondary because somehow they think it is a good idea.
 
petersonra said:
agreed.

having said that, I would make sure this is really a grounded system. people do all kinds of screwy things like feeding control panels from a xmfr with an ungrounded secondary because somehow they think it is a good idea.
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Thanks guys! I re-read 240.22 and I understand what it is saying with the Grounded conductor. Looks like there is some rewiring that needs to be done. Awhile back I've seen some fuses that are called Dummy fuses. Since the Grounded conductor wouldn't be in series with over current protection would that also be a way fix this issue?
 
Dobie1979 said:
Thanks guys! I re-read 240.22 and I understand what it is saying with the Grounded conductor. Looks like there is some rewiring that needs to be done. Awhile back I've seen some fuses that are called Dummy fuses. Since the Grounded conductor wouldn't be in series with over current protection would that also be a way fix this issue?
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the dummy fuses are not listed. just disconnect the two wires on the neutral side and wire nut them together. Leave the fuse in place as a spare.
 
petersonra said:
the dummy fuses are not listed. just disconnect the two wires on the neutral side and wire nut them together. Leave the fuse in place as a spare.
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Also, even though the neutral would not be fused, it would still be interrupted by the switch.
 
Is said fuse a part of the equipment or a part of premises wiring?

NEC might not even apply to it.

"dummy fuse not listed". Does it need to be? Is obviously not acceptable if overcurrent protection is required, but when not required might the "dummy fuse" be acceptable?
 
kwired said:
Is said fuse a part of the equipment or a part of premises wiring?

NEC might not even apply to it.

"dummy fuse not listed". Does it need to be? Is obviously not acceptable if overcurrent protection is required, but when not required might the "dummy fuse" be acceptable?
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Someone may correct me on this, but I cannot imagine a situation where the neutral would be prohibited from passing through a fuse but would be required to be interrupted by the switch.
 
ggunn said:
Someone may correct me on this, but I cannot imagine a situation where the neutral would be prohibited from passing through a fuse but would be required to be interrupted by the switch.
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If NEC covered installation you can not put a fuse in a "grounded" (neutral or otherwise) conductor. You can run a grounded conductor through a circuit breaker if it simultaneously opens all conductors of the circuit.
 
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