Neutral current with switch off

[Fred B]

If you use your meter and read zero volts from hot to neutral with the switch off does this prove 0 potential for shock or once you introduced your body to the circuit you have now added a path and voltage could now be there sense your reading?

Not on a MWBC. And not if improperly wired, (spliced multi circuit neutrals). For instance if on switched lighting circuits the act of turning on the shared circuit light will introduce onto the common neutral current and will use all available courses to return and your body can become a part of that circuit.

 

[ActionDave]

If you use your meter and read zero volts from hot to neutral with the switch off does this prove 0 potential for shock or once you introduced your body to the circuit you have now added a path and voltage could now be there sense your reading?

Basically yes, as long as everything is wired properly and like Fred mentions, depending where you are at in the circuit if it's a MWBC. Even with the switch on you could touch the neutral and a grounded object and not get a shock. This is the same situation you would have if you were touching the service gear and a water pipe.

If you have a faulty neutral or a bootleg neutral from another circuit in the same junction box then things get more complicated. I hate people that bootleg neutrals.

 

[Eddie702]

@Spencer125

If your circuit was a multiwire circuit (2 hots sharing a neutral) or (3 hots sharing a neutral) you could have a different outcome.

 

[mbrooke]

Sorry for my ignorance on this subject. But I’m still having trouble with this. Based on everything you have said it seems that a neutral conductor at a light fixture always has a potential for shock, because if shutting off the switch in that room (isolating the load your servicing)doesn’t limit the potential then shutting off the breaker really wouldn’t either? All neutral conductors on connected in the panel and there would be no way to isolate it. So are you saying there is technically no 100% safe way to work on the neutral conductor at that light? Other than shutting of the main for the whole house to eliminate all loads?

Technically yes, however the odds the of the neutral opening between the main disconnect and sub-panel is rare.

Second, the majority of voltage drop, and thus shock potential comes from the final branch circuit.

Typically if you open the branch breaker (breakers if a MWBC) and nobody has mixed the neutral with other circuits (illegal btw) then you are mostly safe.

 

[GoldDigger]

One thing that I think has not been stressed sufficiently is that if there are either mixed (crossed, or paralleled) neutrals or an MWBC with one side still energized there are two different scenarios to consider:

1. Touching the intact neutral wire and a ground at the same time. This will make you an alternate path for any neutral current back to the utility transformer. But in the case of an intact neutral the voltage across your path will be so low that with intact skin the current will not likely be perceptible, let alone dangerous.
2. Interrupting the neutral path in the course of your work on the circuit. (Even as seemingly innocuous as removing the wire nut from a twisted bundle of neutral wires.) This could potentially put full line voltage between a disconnected neutral end and the neutral home run or a ground, and in the absence of GFI protection could be fatal.