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#90682 12/08/04 01:16 AM
Joined: Mar 2001
Posts: 345
T
tdhorne Offline OP
Member
When your plug in tester reads polarity reversal and your wiggy reads 120 volts from ground to neutral and from hot to neutral what two totally different failures can cause this.
--
Tom

[This message has been edited by tdhorne (edited 12-08-2004).]


Tom Horne

"This alternating current stuff is just a fad. It is much too dangerous for general use" Thomas Alva Edison
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#90683 12/08/04 01:29 AM
Joined: Jul 2004
Posts: 9,662
Likes: 4
G
Member
Open neutral upstream and that may be a bad contact in a GFCI receptacle (covered here several times). You are seeing a back circuit through the downstream load.


Greg Fretwell
#90684 12/08/04 11:46 AM
Joined: Nov 2004
Posts: 7
J
Junior Member
I assume you are taking measurements at the receptacle. The tester is saying you have reversed polarity, that means the neutral and live conductor are reversed. It sounds like the grounded conductor (neutral) is connected to the brass colored terminal to which the live conductor is supposed to be connected, and the live conductor is connected to the white or silver colored terminal to which the grounded conductor (neutral) is to be connected.

#90685 12/08/04 04:32 PM
Joined: Jul 2004
Posts: 9,662
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G
Member
John if this is a simple polarity reversal you wouldn't see volts on the brass screw


Greg Fretwell
#90686 12/08/04 04:51 PM
Joined: Feb 2002
Posts: 183
N
Member
If you reverse hot and neutral you would see this. If you roll all 3 lines so hot is on silver, ground is on brass, and neutral is on green, you would also see this.
/mike

#90687 12/10/04 09:45 PM
Joined: Mar 2004
Posts: 785
B
Member
It's an open neutral, nothing else. Most of the cheap plug in testers will show reverse polarity on an open neutral condition since the neutral is now at 120V potential from upstream load.

#90688 12/10/04 09:51 PM
Joined: Mar 2004
Posts: 785
B
Member
Sorry I didn't notice you said 120 from hot to neutral. It must be like mike said,simply reverse polarity. Your getting 120 from neutral to grd because your neutral is really a hot.

#90689 12/11/04 01:08 AM
Joined: Mar 2001
Posts: 345
T
tdhorne Offline OP
Member
How I got the readings described were from a fault from the hot to the Equipment Grounding Conductor with an open in the EGC between the fault and the source.
--
Tom H


Tom Horne

"This alternating current stuff is just a fad. It is much too dangerous for general use" Thomas Alva Edison
#90690 12/11/04 07:52 PM
Joined: Mar 2004
Posts: 785
B
Member
Tom, did and earlier fault cause the EGC to blow apart, then become energized when the breaker was reset?
Just goes to show how trying to guess a problem without being there can make a fool out of you.

#90691 12/12/04 11:01 PM
Joined: Mar 2001
Posts: 345
T
tdhorne Offline OP
Member
Quote
BigB Tom, did and earlier fault cause the EGC to blow apart, then become energized when the breaker was reset?
Just goes to show how trying to guess a problem without being there can make a fool out of you.
So far it appears that the separation of the armor jacket of the old type BX cable caused the fault by cutting into the insulation of the hot conductor.
--
Tom H


Tom Horne

"This alternating current stuff is just a fad. It is much too dangerous for general use" Thomas Alva Edison

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