110v compressor motor wiring

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Aug 31, 2008 | 06:46 PM

Ranger88Den

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Mountain Pass

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110v compressor motor wiring

I’m replacing a motor on my small, approx. 10 gal., compressor w/110v motor. The on/off pressure switch is wired though the motor by the neutral. I was always taught to NEVER wire house switching through/by the neutral. Is this Okay to switch the neutral. Don’t have the NEC handy. Thanks for the help.

Aug 31, 2008 | 08:04 PM

projectSHO89

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From: St Louis

Switching a neutral is incredibly dangerous.

I'd wire it correctly regardless of how it was shipped from the factory (which is probably wrong).

NEC doesn't concern itself with the wiring of a device like this. UL (for US) (or the Canadian equivalent) would be the agency that would have any oversight.

Steve

Aug 31, 2008 | 08:07 PM

Ford_Six

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From: The Big, Oregon

That's mostly so that someone doesn't go and turn off a light switch to change a fixture, then grabs the still live wire.
Ideally, it should switch both.

Sep 1, 2008 | 04:32 AM

fixnair

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From: Sapulpa OK

Worked on a water heater in mexico yeasrs ago and first thing I did was open the circuit breaker. Then went to work disconnecting the wiring and just for grins I thought I would test it with my meter. Glad I did because as it turns out the breaker was switching the neutral. That could have been my last job!

Sep 1, 2008 | 09:47 AM

MisterCMK

Fleet Owner

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From: Blue Hill Township

The garage at the house I live in now had the lights wired up so that they were switching the neutral. I have since fixed it but I can't help but shake my head at the hacks that do that kind of crap.

Sep 4, 2008 | 07:12 AM

Ranger88Den

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Mountain Pass

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Wired the new motor and switched the hot. Everything working fine. Thanks for the help.

Sep 4, 2008 | 09:02 AM

quaddriver

Cargo Master

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From: Cook Forest and Irwin PA

well if I read you right, the compressor mounted shutoff switch was wired this way, the swtich that shuts off the motor at a certain pressure and unloads the output line, and then turns it back on on a pressure drop?

the reason being, if the compressor is grounded (as it should be) or the piping (if installed) then if there is a switch fault or moisture/shavings in the line, you dont get an internal short (plus if the compressor is truly 110v and is plugged in behind a 20-pass20 GFI, it will trip on moderately humid days)