Old wires--which ones go together?

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Old 08-10-14, 05:11 PM
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Old wires--which ones go together?

I'm replacing several circuit breakers w/ AFCI breakers. The first three were easy. I just followed the black and white wires and reconnected everything according to instructions.

The fourth circuit seems to use older wiring and the insulation is not black or white. The wiring bundle that enters the breaker box looks like it holds 5 different wires all the same color. Some of them are connected to white lines through wire nuts that go to the neutral bar.

The question is, how do I figure out which neutral wire belongs to the load wire that belongs to the breaker I am replacing?
 
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Old 08-10-14, 05:23 PM
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an easy way would require an amp meter.

put a load on the circuit...........8....12 amps go find the same load on one of your white wires

turn the breaker off to confirm
 
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Old 08-10-14, 05:24 PM
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It sounds like someone is using the panel as a junction point,is there also a bundle that go to the line side of the breaker? If so connect the same way as the other 3circuits except use the pigtails that go from the bundle of white to the neutral connect it to the AFCI ,and the same with the black.
Geo
 
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Old 08-10-14, 08:43 PM
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The amp meter is one way of determining which neutral is associated with each hot wire but further checking needs to be done in case that neutral is used in a MWBC.
 
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Old 08-11-14, 04:57 AM
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I believe I misunderstood your post so forget my last post ,the best option would be a clamp on type amp meter as stated.
Geo
 
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Old 08-11-14, 05:16 AM
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The wiring bundle that enters the breaker box looks like it holds 5 different wires all the same color.
The amp meter is one way of determining which neutral is associated with each hot wire but further checking needs to be done in case that neutral is used in a MWBC.
PJ is correct, this sounds like its likely a MWBC ... don't monkey around with disconnecting neutrals in your panel, you should consult a qualified electrician.
 
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Old 08-11-14, 05:43 AM
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The amp meter is one way of determining which neutral is associated with each hot wire but further checking needs to be done in case that neutral is used in a MWBC.
PJmax is right.

.
 

Last edited by ray2047; 08-11-14 at 07:04 AM. Reason: Trim quote and remove non relevant text
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Old 08-11-14, 06:41 AM
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The question is, how do I figure out which neutral wire belongs to the load wire that belongs to the breaker I am replacing?

an easy way would require a clamp on type amp meter.

put a load on the circuit...........8....12 amps go find the same load on one of your white wires

turn the breaker off to confirm

if you find a white that drops to zero when your breaker is turned off ....that white is the neutral for that hot...............probably

BUT ......what if you do not find a white wire with the same amp load as the hot THAT GOES ON AND OFF WITH YOUR BREAKER?

It could mean that you have a split circuit (aka a MWBC, Multiwire Branch Circuit )

NOW...using the amp meter.....check each white wire in turn.....until you find a white wire that you can change the load by turning your breaker on and off.

SAY...your breaker is reading a load of 15 amps..............the amp meter on a white wire is reading a load of 9 amp................you turn the breaker off...........the amp meter goes to 6 amps.

I WOULD THINK ..i have a split circuit and the other breaker has a load of 6 amps.

THE OTHER BREAKER SHOULD BE BESIDE THE FIRST BREAKER...............but could be anywhere in the panel.


read the electric code for yourself .ASK THE BUILDING DEPT. WHICH CODE TO USE....

the great state of Florida is still using the 2008 NEC.
GOOGLE NEC pdf 2014

GOOGLE FOR 2014 CODE https://archive.org/details/nfpa.nec.2014

GOOGLE FOR 2011 CODE https://archive.org/stream/gov.law.n...ge/n0/mode/2up

GOOGLE FOR 2008 CODE https://archive.org/stream/gov.al.el...ge/n7/mode/2up
 
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