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Thread: Open Neutral
12-17-2010, 04:15 PM #1
How bad is an open neutral ?? Here's the odd think about it. Three outlets on the living room wall in a new house had open neutral only on the TOP outlet not on the bottom.
Neutral Side Hot side
*white on screw *Red in back
*white on screw *Red on top screw
*Ground *Black on screw
*Black double tapped on screw
Wiring diagram of outlet
Last edited by Sam Morris; 12-17-2010 at 05:28 PM. Reason: added wiring diagram
12-17-2010, 04:20 PM #2
Re: Open Neutral
Not seeing what you are trying to show in that photo, but ... if you are referring to the tabs being broken off, that is why they are there - so the electrician can supply the top half of the receptacle separate from the bottom half (usually found with switched top halves).
12-17-2010, 04:34 PM #3
Re: Open Neutral
Bet there is no overhead light fixture/luminaire in the living room.
Not uncommon to have a switch loop operating multiple "halves" or split yoke receptacles for a room such as a living room, without an overhead light - so as to provide light via a lamp plugged into anyone of those locations (half the duplex) and switched on from a switch near the room entry. Might also be a three-way switch situation for example (or even three or more locations), if near a foyer or entry door, and from a hall leading to other living areas for example.
It also wouldn't be the first time somebody didn't pigtail and made a wiring error.
You have pictured a duplex receptacle. It is possible to break the tabs and supply from more than one circuit, or as the example above - with a switch loop for half and an always on for the other half, even if from the same circuit.
Contact an electrician. An "open neutral" is obviously something which needs to be identified and corrected.
12-17-2010, 07:41 PM #4
Re: Open Neutral
It sounds like for the switched half of the outlet, the switch is either opening the neutral wire, or somehow hot and neutral have gotten reversed.
John Kogel, RHI, BC HI Lic #47455
12-17-2010, 09:50 PM #5
Re: Open Neutral
Also, if you don't already, you might want to carry a basic two-wire tester ("wiggie"). My 3-prong tester is great for getting my attention but as soon as I find a problem I always verify the problem with a separate tester to be sure. It's amazing how often the three-prong was just not making contact with the right parts. In your situation with the 3 outlets I'll concede it's very unlikely but just food for thought....
12-18-2010, 07:45 AM #6
Re: Open Neutral
Originally Posted by Edited Later by Sam Morris to add
You have failed to identify if either or both of the tabs on the receptacle strap (one on the hot side, one on the neutral side) are present and/or have been removed. You would have to check the wiring on each and every receptacle and/or outlet or junction box.
What I gather from your description is that this receptacle has been wired incorrectly.
First, no screw connection point may contain more than one conductor - that in and of itself is a violation. The terminal screw points are not rated for more than one conductor. They are termination points therefore they may further not host a concutor which has been intermittantly stripped and continues on in its wiring path (i.e. not terminated) (the black screw).
Next you have indicated there is no conductor at the ground screw. Your picture is not clear, but even IF the wiring method is one which employs bonded metallic raceway and metal junction boxes - the receptacle itself should be positively bonded, not reliant upon a self-grounding mount, should the receptacle even be so rated (and this would require contact in two places, be securely mounted and without isolation or mounting washers (those paper washers) to the metallic "plaster ring" which has been properly installed/bonded. I see no such ring in the poor photo. If your electrical system is older and does NOT provide a grounding conductor (wire conductor, bonded metallic cable jacket so rated, bonded metallic conduit, etc.) and your previous 2-slot receptacles have been replaced with three-slot (grounding type) receptacles your 3-light tester would likely indicate "open neutral". Three-light testers should NEVER be used with 2-wire "systems" (no equipment ground) EVEN if that circuit is protected by a GFCI.
It is apparent from your description that the duplex receptacle has been wired in a "feed-through" manner, at least on the top. This again is a no-no. The receptacle device has not been "pigtailed" for either of its individual receptacles. The receptacle devices should be wired via short lengths of wire which maintain continuity and connection for the circuit even when the device itself is removed.
Finally, If indeed the "TOP" half of the three receptacles are switch controlled (switch loop), you would need to assure that there has not been a wiring error in that switch circuit. "power from the panel" location must be determined - and the switched conductor MUST be the "HOT" condutor and not the "neutral" (actually groundED conductor). Switch loop conductors (those that "feed" the switch as well as those that come from the switch) are often found to have been used in a manner not in keeping with their original insulation color identification (IF there are different colorations!) especially in older homes. There are limitations as to how and when re-marking an otherwise "identified" conductor may be used in a switch loop - but this was not always done, and the "rules" were not always followed correctly in their use. Present NEC (2011 edition) standards/rules require switches/switch loops to be wired more safely now to avoid this and other hazards.
Tracing wiring, discussing the nuances, etc. is beyond the usual for this site, and not something which should be undertaken by the inexperienced or unqualified.
Since you have chosen to alter your original post, but not provide the most basic and important information regarding the condition of the receptacle device or respond to more recent posted information/questions; just to edit the original post by adding a "wiring diagram" "word picture" - which is lacking (tabs - one or both having been removed? no mention of the other two receptacles which supposedly have issues - no response regarding switch loop - no way to know if without a switchloop if the receptacles are wired via MWBC OR two DIFFERENT circuits - then one wonders if they are on the same half phase bus!) leads me to believe that the subject is beyond your skill set. No mention of the wiring method employed has been made.
I STRONGLY recommend deferral to a qualifed electrician/electrical contractor: In case it wasn't clear - An actual intermittant or Open Neutral on a receptacle circuit IS A VERY "BAD" THING, which can lead to injury, fire, and/or death. However, your description and information as incomplete as it is suggests a host of other possibilities including some nearly as "bad" and some just as "bad", as well as other slightly less "bad"; or it may be that the "tester" (person using the testing device) used same inappropriately in a situation in which it should not have been employed).
Considering the above, and with the suspicion/concern that you have made a very basic safety issue type of inquiry, yet again, recommend a qualified electrician evaluate and correct as necessary, and that if you are indeed a HI, that you consider some intense self-study in conjunction with a comprehensive basic level CE in the Electrical area (something other than an on-line point and click program), because from the pattern of your posts, this appears to be an area you are weak in.
To investigate, trace, test, requires skills, knowledge and equipment beyond a plug-in three-light tester. One should read, and understand the directions and information contained in said three-light tester before using same. Plugging same into a receptacle with the face plate off, and which can move (the receptacle device - to and fro) when said cover is off is UNWISE, esp. without PPE. Checking for continuity, verifying connections, and determining if for example the cabling has been pierced by a fastener a host of things could have occured, even in a never occupied new construction home.
That is of course what would be S.O.P. and in keeping with the S.o.P (deferring to an electrician). If actually HI reporting, report what you observed and defer.
I would expect a "new house" to have modern wiring methods employed (i.e. Receptacles "pigtailed" not fed-through, and the presence of an actual egc conductor wire to receptacles' groundING screw terminal - be it two-wire plus other conductor method for egc and a grounding conductor from a grounding screw on the back of the metallic junction box, or actual groundING wire for conductor, and/or MWBCs cabling with pigtail to the receptacle). I would never expect a black insulated conductor connected to a groundING screw - such is never allowed for a 15 or 20 amp circuit.
However, if "lived in" even a day, a DIY owner may have altered. For example one or more of thse receptacles may not have had switch control only the top half - but for the entire receptacle yoke, and the owner may have wanted only "half" or one receptacle per outlet location to be switched - or a DIY owner may have replaced the receptacles due to a decorating/color or style change and messed up the replacement.
However, the not-to-be-wired-feed-through has been around for a while - and so has the practice of NOT relying on self-grounding even if metallic junction boxes are bonded - but to utilize a bare or a green insulated groundING conductor so as to assure bonding and equipment grounding conductor for the utilization equipment connected to the receptacle.
Last edited by H.G. Watson, Sr.; 12-18-2010 at 08:32 AM.