ANOTHER ELECTRICAL QUESTION

[grsthegreat]

We still don't know why which white/neutral is matched to which black/red/hot matters. I can't think of a reason.

And we still don't have pictures to help explain the panel itself.

there can be many reasons, such as switching a 120 circuit to a 220 circuit.

 

[grsthegreat]

My clamp style amp meter quit a long time ago but I have a new one ordered. If I have for instance a 9 amp load on a particular circuit I know the clamp meter should register 9 amps on the hot (black) wire. Will the clamp meter register 9 amps on the corresponding neutral (white) wire? If so, that's the answer.

. no, not how this works see LouNY answer. thats the easiest way

 

[LouNY]

I can think of two quite easily;
a ground fault breaker,
or a 220/240 volt circuit.
Both legitimate and legal uses.

 

[k0ua]

It's only 12 circuits,
kill all the power,
disconnect the neutrals,
go to the far end of the circuit you are interested in twist or bung the hot and neutral together,
come back to the panel and use your meter for continuity only one pair will have it,
grab a neutral wire and start down the breakers and repeat.
Piece of cake

In the lighting circuits make sure the light switches are OFF. Because if he still has incandescent bulbs and the switches are on, the low resistance of the lamps will cause the continuity tester to believe this is the one circuit he has shorted out.

But yes generally given the low number of circuits under test, your method is probably the easiest.

 

[Industrial Toys]

I had that issue too, installing ARC fault breakers. Waste of time as they are falsing and will be going into the garbage. I just dug around and probably removed the probable one, then testing the circuit.

I have all kinds of inductive testers and yet nothing I think would find which neutral is paired to a hot. I would just remove one neutral at a time until you loose power in the circuit.

 

[LouNY]

If a person is concerned about false readings on a conductivity meter,
which is possible with poor connections or cheaper meters,
use a 9 volt battery at the far end and look for DC voltage.

Nine volt batteries can have many uses,
years ago I needed a 90 volt DC low current power supply to test some equipment,
stop at a hardware store and grabbed a box of 9 volt batterys and clipped them together in series a couple of 20 gauge jumpers and of to work we went.

 

[Industrial Toys]

Why an old SIMPSON meter gives better readings than many digital ones. ESPECIALLY if it's not your strong suit.

 

[MossRoad]

... I would just remove one neutral at a time until you loose power in the circuit.

Yep. Plug a loud radio into the circuit so that you can hear it from the panel.
Kill power, remove a neutral, restore power, listen, repeat.
Number the neutrals for future reference if desired.

 

[CobyRupert]

You can buy a clamp style "AMP" meter that will clamp around the wire and do this testing safely and quickly. Follow mwayne's direction.

This.
Make sure each circuit’s amperage is unique enough compared to the other circuit’s current to identify.
Hot wire and neutral wire of a circuit should have the same exact measured amperage (current).
...unless someone has connected neutrals from different circuits together downstream, or somebody bonded a (white) neutral and (green) ground wire together downstream (and the ground wire becomes a parallel “neutral” current path).

 

[CobyRupert]

Another (easier) way to identify:
1. Make sure each circuit has a load plugged into it and turned “on”.
2. Turn off all breakers.
3. Disconnect 1 neutral wire in the panel.
4. Systematically turn breakers on/off until you measure 120v between the disconnected neutral wire and anything grounded (e.g. the panel, neutral bus, etc). The breaker you turned to get 120V on the neutral wire corresponds with that neutral wire.

This works because there is no current flowing in the circuit with the disconnected neutral, thus no voltage drop across the load, thus the whole “circuit”, including the disconnected neutral wire is at 120V.