Electronic – Phantom Voltage When Near Outlet

acmultimeteroutletvoltage

I am pretty new to electronics, and have mainly worked with DC circuits. I'm majoring in Computer Science, but I also find electrical engineering interesting, so I am learning as much as I can. Well, my multimeter measures about 0.050 to 0.100mV when not connected to anything. As soon as I move close to the wall outlet, it creeps up to 0.1 volts, then 2 volts, then when I am pretty close to it, it reads about 4 – 6 volts. Also, when I plug one lead into the hot or neutral, why does it read 6 volts or more? And between neutral and ground, it usually reads 0.4 volts when there is minimal load on the outlet. I heard that that is normal, but is 4.4 volts from neutral to ground normal when a 1300W heater is running? Thank you for your help. I'm still learning, so these questions may sound stupid. And yes, I am taking safety precautions so that I do not get shocked.

Best Answer

0.050 to 0.100mV when not connected to anything

This is pretty normal. It's not a big number and probably just represents the noise floor of your multimeter.

As soon as I move close to the wall outlet, it creeps up to 0.1 volts, then 2 volts, then when I am pretty close to it, it reads about 4 - 6 volts.

Also pretty normal. The electric fields emanating from house AC wiring can make a multimeter show these kind of voltages when close up. It's mainly due to the electric fields capacitively coupling to you probes with your body acting as a capacitor to ground. It would be interesting to see what the voltage drops to when you stop holding the multimeter - I would expect it to still register a number but a smaller number.

between neutral and ground, it usually reads 0.4 volts when there is minimal load on the outlet. I heard that that is normal, but is 4.4 volts from neutral to ground normal when a 1300W heater is running?

4.4 volts is certainly no un-heard of. Usually neutral is connected to earth at some point between your house and the local sub-station and given the volt drop down the neutral wire when passing several amps this would be fairly commonplace.