Earth Fault?

[darkle]

Hi Guys came across this one when I was installing a bathroom fan. When I took the old fan down which had blown, I tested the wires and noted the following; Between active and neutral 240 between active and earth 120v the same on the Switched Active but when I turned off the lights the voltage incresed to 227v. Does this mean I have a fault to earth?

Cheers for any help

-Michael

 

[GLENNSPARK]

Well thats a hell ov a volt drop...........

 

[darkle]

Thats what I thought. Any suggestions? Does this mean I have an active conductor in contact with earth somewhere in the circuit? If so why would it be dropping when the I turn the lights on, I mean I could understand the switched active, but why would the active be influenced by the light switch?

 

[GLENNSPARK]

You could IR test the circuit in question mate............Test between all conductors and make sure that when you do that nowt else sensitive is connected to the circuit you are testing (so isolate the circuit under test from any others first wont you mate).............

 

[JUD]

Thats what I thought. Any suggestions? Does this mean I have an active conductor in contact with earth somewhere in the circuit? If so why would it be dropping when the I turn the lights on, I mean I could understand the switched active, but why would the active be influenced by the light switch?

You're very active.

They're called line conductors​ these days.

 

[darkle]

The lighting circuit is full of low voltage transformers, do they affect IR readings? If there is a voltage drop does this mean its dropping across something not earthed? If there is a fault to earth why would breaker not trip?

 

[darkle]

Not enough fault current? Sorry just trying to rattle off ideas.

 

[GLENNSPARK]

The lighting circuit is full of low voltage transformers, do they affect IR readings? If there is a voltage drop does this mean its dropping across something not earthed? If there is a fault to earth why would breaker not trip?

trannys are ELV mate (extra low voltage) dont forget terminology here.......How many loads are connected and how longs the cable run and what size is it?..........the problem with radials is you get volt-drops appearing as length increases and loads are applied.....

 

[Monkey]

Darkle,

start at the begining check at the mains first I had this the other day 210 volts at the end of line

found 210 coming in some times over thinking blinds us just a thought

also I find as Glennspark says do some basic checks get it clear in your head good luck

 

[darkle]

Ok fair call, sorry. There are probably 15 elv downlights in the bathroom on 1mm 2C + E maybe 30 m run.