Line to Earth fault 70 volts?!?

[iamgary25]

Just tested a lighting circuit to find that the voltage between Line and Neutral was 240V and Line to Earth was around 70 volts? What could this be? a short between Line and Earth? Also the circuit is on a 6A 30mA RCBO but doesn't trip, the test button works though...

thanks

 

[Plonker 3]

What testing did you carry out, and what test equipment did you use ?

 

[iamgary25]

A Megger Voltage indicator... i tested another lighting circuit on another RCBO and i got 240 L to E etc...

 

[Plonker 3]

Time to get the test equipment out and carry out IR, continuity of conductors. RCD times and ramp test then.

 

[Richard Burns]

Presumably a loose earth connection on that circuit that has a resistance providing a voltage drop of about 170 volts so you only see 70V.

 

[iamgary25]

ok thanks for the advice will get onto this tomorrow.

 

[Knobhead]

Time to get the test equipment out and carry out IR, continuity of conductors. RCD times and ramp test then.

Don't confuse him Dillb. He missed a couple of days out of the 5 weeks.

 

[Lucien Nunes]

Line to Earth was around 70 volts? What could this be? a short between Line and Earth

Does not compute... you can't have a voltage across a short!

 

[nickblake]

Test kit out ,if you have 70 volts between line and earth your earth is possibly open circuit , and if all was ok and you had a line to earth fault i would expect a Bang !!! so you need to carry out an r1r2 test ,ir test etc

 

[Besoeker]

Just tested a lighting circuit to find that the voltage between Line and Neutral was 240V and Line to Earth was around 70 volts? What could this be? a short between Line and Earth?

A problem possibly but 70V is hardly indicative of a short circuit.
Maybe the neutral not connected to earth so the system is floating?
Have you checked that?