Beautiful Two Neutral Wires

A meter can identify the voltage but might not be more useful.

Two neutral wires. Switch the main breaker off. When there is two neutral wires in one hole on the neutral bar of an electrical panel several things may happen. Connect the short white pigtail wire to the neutral terminal.

Use a phase tester screw driver to identify the hot. The magnitude of the current in the neutral equals that of the other two wires. Make sure the second black is not hot.

Neutral wires are usually connected at a neutral bus within panelboards or switchboards. One is that the wires may be from two different circuits and that the loading of these two neutral wires may fluctuate. Please read this long answer to understand why.

This fluctuation causes the wires to slightly expand and contract and over time the connection gradually becomes loose. The circuit s neutral wire is in the junction box holding the light fixture. The neutral goes to one pin of your lamp.

Once in an awhile if the connection becomes loose enough you may hear a. However if you need to rewire a light switch or a plug socket you may occasionally come across two black wires. The easiest and safest way is to use a multimeter to test for current.

A second exception to the one wire per terminal rule is that two or sometimes three ground wires can be secured at one terminal but it is dependent on the manufacturer s installation instructions and the wire size. Roy long s answer is technically correct however. For smart switches that function without a neutral wire a home hub is essential.