weird lighting fault

[Dean Williams]

Hi folks
while testing this theatre, i attempted to get a Zs from an emergency exit sign. The steel conduit is being used as cpc.
when i connect my three probes to l,n,earth i'm getting 110v on the screen and when i press test it comes up with about 160 ohms.
i put a voltmeter across and found 110v between L and E but 230v between L and N.
could this be a poor connection on the steel conduit cpc and if so, why does the voltage drop to approx 110v

thanks...its a bit of a puzzle

 

[telectrix]

do a R2 test on the conduit end to end. then test to MET.

 

[Dean Williams]

from the board to the fitting is about 300 metres...

 

[telectrix]

even if it's 3000m you've got to get it right, one way or another. do it in stages with a wander lead.

 

[Dean Williams]

that will be fun, all the conduit is buried in walls and in ceilings to which there is no access. Thanks

 

[Dean Williams]

assuming it is a bad earth, can someone please explain the science behind it...how does it become 110v???

 

[Guest 004]

sounds like a break in the conduit to the fitting, just code 1 it, and recommend rcbo

 

[telectrix]

code 1 it and FIX it. you don't put a band- aid on an arterial bleed.

 

[Dean Williams]

thanks. the conduit is 35 years old!
just dont understand why its 110v

 

[Dean Williams]

i will....i just want to get my head round the reason as to why the voltage drops to 110v

 

[Guest 004]

probably getting a reading through the damp walls, and forgot to mention, you should not walk away from a code 1, without isolating or rectifying.

 

[telectrix]

floating earth?

 

[Dean Williams]

i'd be there forever and a day if i rectified all 76 code 1s that ive found so far!!!

 

[Guest 004]

There should be an agreement of what to do, as you find the code 1's

 

[telectrix]

only 76, must have been done on a good day.