strange ins res results??

[lister]

newley installaed ring main with 15 socket outlets on it, ( just second fixed so nothing plugged in) when testing end to end resistances loop etc all ok but when insulation testing phase to cpc 48.0 meg neutral to cpc 148.0 meg and phase to neutral 250.0 meg
is the 48 meg result low enough to cause concern and any ideas ??
double checked every thing - all ok

 

[Spudnik]

Assuming you tested at 500V?

How long did you press the test button for?

Did the reading creep up?

Sometimes it can take a few seconds for the circuit to charge up.

 

[Mr Mark Sparks]

all the readings are a pass but brand new i would expect the meter to top out >299 on mine at 500v
it may be worth popping the socket fronts off and having a look behind for pinched cables it will be hard to spot because the readings are not to bad

 

[lister]

thanks for the replys chaps,
auto test so can only press once- if you see what i mean,(metrel 6557) tested several times reading stayed the same give or take a meg out of interest i did give it a blast at 1000V just for the hell of it and reading came back about the same?(just been calibrated as well)
checked every thing again- nowt. circuit now live and has been in use by builders all day ( touch wood no probs)
so would you worry about it or not.

 

[Mr Mark Sparks]

no dont worry as i said ideal would be better maybe new cable a bit iffy
i did a house years ago and nothing was above 200meg (tester red up to 999 then)
never found out why