Mainline (Strange Voltage Measurement)

[hpleung]

Hi,

I am doing the voltage measurement for the first time at step "Clip the black lead of your Digital MultiMeter to 31U. Clip the red lead of your DMM to 32U. Make sure that the metal ends of the two test leads cannot touch each other. Set your DMM to AC volts in the appropriate range."

When the switch is on - i read a 118.2 AC Volts.

When the switch is off - i read a 24.6 volts. ==> Should not this be zero?

Thanks.

 

[Paul Birkeland]

What you're measuring is the voltage difference between the powerline neutral and a wire that is connected to nothing but running right next to a wire carrying 120V, so there may be a bit of coupling going on there.  There's really no oomph behind this though, when the power transformer primary wiring is complete that should go away. 

 

[hpleung]

Got it.  Thanks. Will check the voltage again later.