ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Top Posters(30 Days)
Potseal 11
Recent Posts
Why cables look like they do
by LongRunner. 04/26/17 09:36 AM
Dimmable LED 2x4 lay in fixtures
by HotLine1. 04/24/17 05:43 PM
Old decora style outlets
by Lostazhell. 04/22/17 07:59 PM
Permit Snafus...AHJs and Contractors Jump in
by gfretwell. 04/22/17 01:11 PM
How do you find a good employee?
by HotLine1. 04/22/17 10:44 AM
New in the Gallery:
SE cable question
Popular Topics(Views)
234,809 Are you busy
169,579 Re: Forum
162,839 Need opinion
Who's Online Now
0 registered members (), 91 guests, and 8 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate This Thread
#90682 - 12/08/04 01:16 AM Polarity testing  
tdhorne  Offline
Member
Joined: Mar 2001
Posts: 345
Maryland, USA
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

2017 / 2014 NEC & Related Books and Study Guides

#90683 - 12/08/04 01:29 AM Re: Polarity testing  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,069
Estero,Fl,usa
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 Re: Polarity testing  
John M Caloggero  Offline
Junior Member
Joined: Nov 2004
Posts: 7
Virginia Beach VA
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 Re: Polarity testing  
gfretwell  Offline


Member
Joined: Jul 2004
Posts: 9,069
Estero,Fl,usa
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 Re: Polarity testing  
n1ist  Offline
Member
Joined: Feb 2002
Posts: 183
Malden MA
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 Re: Polarity testing  
BigB  Offline
Member
Joined: Mar 2004
Posts: 719
Tucson, AZ USA
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 Re: Polarity testing  
BigB  Offline
Member
Joined: Mar 2004
Posts: 719
Tucson, AZ USA
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 Re: Polarity testing  
tdhorne  Offline
Member
Joined: Mar 2001
Posts: 345
Maryland, USA
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 Re: Polarity testing  
BigB  Offline
Member
Joined: Mar 2004
Posts: 719
Tucson, AZ USA
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 Re: Polarity testing  
tdhorne  Offline
Member
Joined: Mar 2001
Posts: 345
Maryland, USA
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


Member Spotlight
cookcc
cookcc
California ,Long Beach
Posts: 28
Joined: May 2007
Show All Member Profiles 
Featured:

2017 NEC and Related
2017 NEC
Now Available!

Shout Box
Powered by UBB.threads™ PHP Forum Software 7.6.0
Page Time: 0.016s Queries: 14 (0.004s) Memory: 0.8080 MB (Peak: 0.9841 MB) Zlib enabled. Server Time: 2017-04-27 14:54:12 UTC