voltage query

[jon090]

Hi, iv changed an outside light for a customer and completed all the necessary tests. After powering up I got 230v between L and N but strangely 120v between L and E. The tests were done at the jb prior to the light fitting. Any ideas what could be causing this?

Thanks in advance!

 

[Darkwood]

What were the results of your Earth loop impedance test?
What results for R1 + R2
You tell us you done all the necessary tests so please post your findings then we can better assist you.

 

[jon090]

R1 R2 - 0.34
Zs - 0.41

 

[Plonker 3]

What voltage was showing on your tester when you carried out the Zs? As my tester show the voltage between conductors and wont allow me to carry out the test unless the voltage is within a certain range (unsure what it is)

 

[Darkwood]

Ensure you have good contact to earth with probe ...some items are coated with anti corrosion and can give bad contact, check all termination points again and re-do the testing .... see if you are presented with same situe as it dosnt really tally - your results show a good earth, you say you have 230 L/N yet it seems to show a bad earth L/E.

 

[jon090]

Fair point that.. Cant remeber tbh. Ill head back later on redo a couple tests and take some pics!

 

[tony mc]

I would re test the cct making sure you have good connections and as mentioned check what voltage you loop tester is testing on the EFLI.

 

[Edd]

The fault you have described, 120 L-E points towards a loss of earth, but as you say you have carried out the tests and got good readings! When you go back I'm sure the fault will be staring at you in the face.. Please let us know what you find. Theres too many threads where we miss out on the final find

 

[tony mc]

What voltage do you get at the CU between earth? As Edd says it will be something staring you in the face !

 

[jon090]

Just to update you all.. Went back, retested and strangely all was fine. L to E 230. Only thing I can think is what dark wood said and the connectors where possibly coated throwing my tester off! Cheers guys

 

[Darkwood]

You said you had 230 L/N and the reading for ELI and R1/R2 were fine so all pointed to a bad lead on tester or poor contact....if this re-occurs elsewhere replace test leads and have meter calibrated or new voltage tester.... either way always best to carry a back-up like a cheap multi-meter.... just because the computer says yes it dont mean its ok all the time.
I had a multimeter that showed 430v to earth on a 3ph system and turned out to be a fault on meter.