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Fused Neutrals


Wayne Wildermuth
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Guys I can tell ya that I have worked on several houses built in the 20s 30s and 40s and it is very common for the neutrals to be connected to a switch going to a lighting outlet or recepticle outlet. It only took me one time, sitting on an old cast iron heating grate changing a recepticle that I had turned off at the switch to figure out neutrals are switched. I thought the switch was bad. I pulled the wires off of the switch and it was still hot at the plug. I was in denial that someone swtched those neutrals. I spoke to an old electrician buddy of mine and he said, Oh yeah we used to do it all the time.

T.

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  • 3 weeks later...

The NEC does not permit fuses in neutrals or in the grounding conductor. The fundamental principal is to keep the neutral(grounded conductor) and the grounding conductors at ground protential. If either of them is disconnected without simultaneously opening all phases, there will be a voltage between many parts of the system and the earth. In addition the neutral and grounding conductor(s) carry fault current during phase to ground faults. If is is diconnected there is no path and phase protection may not function.

NEC 2005 and earlier

"240.22 Grounded Conductor

No overcurrent device shall be connected in series with any conductor that is intentionally grounded, unless one of the following two conditions is met:

(1) The overcurrent device opens all conductors of the circuit, including the grounded conductor, and is designed so that no pole can operate independently."

See also NEC Paragraph 240.4 General Requirements for grounding and bonding.

Fusing a neutral is a big NO-NO.

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Originally posted by Trailblazer

The NEC does not permit fuses in neutrals or in the grounding conductor. The fundamental principal is to keep the neutral(grounded conductor) and the grounding conductors at ground protential. If either of them is disconnected without simultaneously opening all phases, there will be a voltage between many parts of the system and the earth. In addition the neutral and grounding conductor(s) carry fault current during phase to ground faults. If is is diconnected there is no path and phase protection may not function.

NEC 2005 and earlier

"240.22 Grounded Conductor

No overcurrent device shall be connected in series with any conductor that is intentionally grounded, unless one of the following two conditions is met:

(1) The overcurrent device opens all conductors of the circuit, including the grounded conductor, and is designed so that no pole can operate independently."

See also NEC Paragraph 240.4 General Requirements for grounding and bonding.

Fusing a neutral is a big NO-NO.

George, welcome to the forum. I hope you stick around.

In his original question, I think that Wayne understands what a fused neutral is and what its implications are, but he's looking for reporting language to convey that information to his clients.

As home inspectors, we have the difficult task of explaining this stuff to a non-technical audience. We've got to be able to recognize a problem and then explain it to folks who are CPAs, soccer moms and software consultants.

Here's an interesting challenge for you that will help you to understand what we do:

Take the explanation in your paragraph and re-write it for a non-technical audience. Explain:

A. What the problem is.

B. Why it's important. That is, what "bad thing" could happen if no action is taken?

C. What the homebuyer should do. That is, what action should he take?

Remember that the explanation must be understood by someone who doesn't know the meaning of words like "volt," "watt," "grounding," etc. In other words, explain it so that Aunt Martha can understand it.

Oh yes, keep it short, you've got 40 or 50 other defects to write about on this house. I'd suggest aiming for 50-100 words. And no spelling or grammar mistakes allowed. Some of your customers might be schoolteachers.

- Jim Katen, Oregon

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