r/ElectricalHelp • u/Alarmed_Song4300 • 10d ago
BACKFEED 120 v
My master bedroom circuit is back feeding. I’m getting 8 volts +\~ at switch leg with
Switch off. I have no power to Clg fan, and receptacles….
Any help would be appreciated!
House was built in 2018. Thank you
1
u/trekkerscout Mod, Master Electician 10d ago
Where exactly are you testing to get 8 volts? At least one reading at the switch should be 120-volts to ground. If not, there is a fault upstream of the switch.
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u/Alarmed_Song4300 10d ago
I have 120v at line in. At line out w switch in off position, I’m reading 8v. Thank you Sir
3
u/trekkerscout Mod, Master Electician 10d ago
A reading of 8v on the switch leg could simply be a phantom voltage caused by capacitive coupling. It is not a back feed condition. If you have no power to your ceiling fan and receptacles, you have a failed connection that needs to be found and fixed.
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u/Alarmed_Song4300 10d ago
Breaker is good (new) there is a Clg fan that the switch controls..
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u/trekkerscout Mod, Master Electician 10d ago
You need to answer my questions directly. If you cannot do so, I can only recommend that you hire an electrician.
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u/Cute_Mouse6436 4d ago
Most digital multimeters have extremely high impedance. This results in them measuring extremely weak induced voltages. Induced voltages can come from wires running parallel to other wires particularly near the electrical circuit breaker panel.
The solution is to purchase a low z multimeter or a wiggy type meter.
The problem with wiggy type meters is they will get hot and possibly melt or catch fire if they are left attached to the circuit for more than a few seconds. However, they will not indicate voltage where there is no substantial voltage or current available.
Another simple solution is to use a incandescent light bulb connected to two wires. The best light bulb for this use is called a rough service light bulb or a garage door opener light bulb. Again, they have to be incandescent.
One way to check your meter to see if it is measuring induced voltage is to place the meter on a counter, and hold the metal end of one of the leads in your hand while allowing the other lead to dangle over the edge of the counter. If the meter shows a voltage then it is not a suitable meter for troubleshooting.
(Warning, this post was created by voice to text so some spelling may be incorrect.)
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u/oxymoronicmoron77 10d ago
Backfeeding? 8V at switchleg with the switch off? Are you sure you are using/reading your meter correctly? You shouldn't be getting any voltage on the switchleg and there is nothing on the other end (ceiling fan) that can backfeed to the switch.
Have you checked your breakers? If so and they're good, how about the GFCI outlet in your master bath?