IR Faultfinding

[Steve D]

Hi All,

I've got a C&G 2330 practical exam on insp & testing and faultfinding on tuesday.

When performing an IR test on a ring for example to try to identify a fault, I've read somewhere to set the meter to 250V instead of 500V.

Is this right, and if so can you explain why please ?

Cheers
Steve

 

[Mr Mark Sparks]

the only reason i can see to do that is so you dont harm any load still plugged in
i dont know if this is correct when doing your exam though
i would say it is good practice though to try 250 first

 

[Steve D]

Cheers Mark.

We know there won't be any loads connected as we will be able to see all the sockets in front of us.
If I'm asked why I'm testing at 250V rather than 500V then I just need to be able to jusify myself.

Cheers
Steve

 

[s1m0n]

Hi, I did my practical exam in march, use it on the 500v range as that is what is needed for LV in the regs, 250v is for ELV. see Table 61 of BS7671 regs (page 158).
the caution we had was that we had 4 rcbo's that were vunerable to insulation resistance testing, so the phase was removed from the rcbo for testing ie P-N, P.E.
hope this helps, also if you are on a similar rig, there was a choke in the bath room light, neon on the shower switch and the coil in the DOL to take into concideration.

good luck simon

 

[lockhes]

got mine toorow (monday)

we have never been told to put on 250v setting

you do 500v then if thats low or 0 you do killo ohms setting again if to low you put on normal ohms setting like you would for continuity

then you work out if its low IR or short circuit

hope that helps