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Old 01-11-2009, 06:45 AM   #1
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Detecting Hot Wires

I am converting to rocker swtiches and found out some of my hot wires are white and others black. Is this normal?

I thought White was suppose to be wired to the power source. Red always seems to be a traveller.

Thanks for your help.


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Old 01-11-2009, 07:30 AM   #2
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White can be part of a switch loop also. Are you using a cricket(audible detector)?? They often read eroneously.


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Old 01-11-2009, 09:10 AM   #3
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I am just using a circuit tester light. The switches are 3 ways. You are probably right, the white is part of a switch loop.
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Old 01-11-2009, 01:05 PM   #4
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White can be a traveler or the hot feed to a switch. This means that there is no standard for 3 way switch loop wiring color. White may not be the switched line to the light or other load.

Neutrals must never be switched. Therefore white to a switch is assumed to not be neutral. Non-neutral white wires need to be tagged at both ends with a band of red or black tape or stain.

A nearly (not 100%) reliable method of finding a hot lead is to test its voltage to ground.
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Old 01-11-2009, 04:21 PM   #5
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For quick checking the presence of AC voltages I use a Voltage sniffer.
These use a non-metallic plastic tip probe so it is not necessary to contact metal. The probe will light up and beep when held close to an AC source.
The El-Cheapo 70-1000VAC model: HF Non-Contact Voltage Tester

The sniffer that I prefer is adjustable from 5-1000 VAC so it can be used on low voltage lights, door bells, and thermostat wiring.
Greenlee GT-16 - Non-Contact Adjustable Voltage Detector, AC 5-1000V

The precaution is that like digital voltmeters they can give false positives.
To verify AC voltage rather than using a DMM I prefer a WIGGY, because of its low input impedance will not read phantom voltages as seen sometimes on DMMs.
Klein Tools: Electrical Testers - Wiggy Solenoid Voltage Tester

The name Wiggy is copyrighted so here is the Gardner Bender copy:
Gardner Bender at Lowe's: Solenoid Voltage Tester

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& Stay Safe
.....Bob Lavery
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common vs traveller

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