Open Neutral Identification

Status
Not open for further replies.

iwire

Moderator
Staff member
Location
Massachusetts
My mistake; between the meter and the xfmr. or are we talking about losing the neutral outside of those two points?

The OP seems to be talking about an open neutral between the utility transformer and the house.

Both ends of that will be bonded so detecting an open with a simple circuit is not possible.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
The OP seems to be talking about an open neutral between the utility transformer and the house.

Both ends of that will be bonded so detecting an open with a simple circuit is not possible.
You would need to use a signal injection circuit similar to that used in some GFCIs to test whether you can specifically run current through the neutral wire. But the inline "transformers" (CTs) would have to be able to carry normal and fault neutral current as well.
 

kwired

Electron manager
Location
NE Nebraska
We could stop using grounded conductors for circuits or at least run equipment grounding conductors all the way back to the source on services and have no neutral to ground bonds beyond the source and eliminate many stray voltage and grounded neutral issues. I don't know how to get everyone else on board with either one of those ideas though.
 

iwire

Moderator
Staff member
Location
Massachusetts
You would need to use a signal injection circuit similar to that used in some GFCIs to test whether you can specifically run current through the neutral wire. But the inline "transformers" (CTs) would have to be able to carry normal and fault neutral current as well.

I am sure there are a number of ways, none of them will be a simple continuity test as was suggested.
 
We could stop using grounded conductors for circuits or at least run equipment grounding conductors all the way back to the source on services and have no neutral to ground bonds beyond the source and eliminate many stray voltage and grounded neutral issues. I don't know how to get everyone else on board with either one of those ideas though.

The current on the water line thing does bug me quite a bit just as a matter of principle and consistency - the NEC is all about avoided parallel paths and current on things that arent meant to, and they got rid of the 3 wire feeder between structures :rant:, but then we have the metal water line to you neighbors house..... :dunce:

I guess it is one of the downsides of the grounded system. Another solution would be for the utility to not jumper the secondary and primary neutrals and not serve multiple premises off a single transformer, but that would increase cost for everyone and as you say getting everyone on board would be difficult.
 
That's a good thing to have if you service neutral ever goes bad.

Is it? I am not sure I agree. First, I dont think that is to any degree the purpose of bonding a water line, to act as a backup for the neutral conductor. Second, That just means the problem will go un-noticed until someone breaks the water line, unbalances the voltages, fry's some electronics, and gets a shock as a bonus no?
 
Status
Not open for further replies.
Top