Voltage Measurement on Energized Capacitor: Explained for Rookies

[rabuntjer]

can anyone explain to a rookie in very simple terms why you can measure voltage from a capacitor (or any other electrical device) that is energized and find no current via phase to ground but measured voltage phase to phase. In my job we're taught to measure phase to phase and phase to ground b4 proceeding to work on any electrical devices.

 

[Irid]

What is your ground, when you consider a sole charged capacitor?

 

[capnahab]

This is very simple indeed! When you measure the voltage on a capacitor with a digital meter to ground (who uses Simpson 260s anymore) there is no path for current flow to ground.

That is very smart advice you get at work. I always put my meter on resistance first and check for continuity in the meter leads before proceeding with the measurement. I then check phase to phase and then phase to ground to ensure there is no voltage potential. Sometimes I also check my meter on a known live circuit also to make sure it is working properly. After all of that I touch the electrical part very fast to ensure I don't get a shock. This is from someone who does not need to be reminded anymore.

 

[vanesch]

I always put my meter on resistance first and check for continuity in the meter leads before proceeding with the measurement. I then check phase to phase and then phase to ground to ensure there is no voltage potential.

But don't forget to switch from "resistance" to "voltage" in between

 

[capnahab]

100% right! My biggest problem is after checking current with my Fluke multimeter, I put the voltage measuring leads in the same holes and then blow the meter fuse, a cycle that keeps repeating.