Ring main IR question from todays EICR

[davesparks]

Neons just glow and leave you with a puzzled expression on your face, or laughing at the poor apprentice trying to work out what they've done wrong.

 

[jackhammerJIM]

See posts 10 and 11.

Apologies happyhippydad i must engage my brain before writing

 

[UKMeterman]

Ok
1. 500V is the standard test voltage for pat testing, if anything can be damaged by 500V current limited to 1ma then it shouldn't be plugged in as it would fail the type testing
2. The output of a megger is current limited to about 1mA so it can't power anything.

 

[Lucien Nunes]

The smoothing capacitors giving you the 24Ω L-E reading as a false reading

Not sure I get your meaning here. No capacitor (except a failed one) should affect a reading on a DC insulation test, although suppressors legitimately create AC leakage when energised. Smoothing capacitors would never be connected in any way to E as they are part of the current-using equipment. Did you mean varistors? They might give an unduly low reading L-E at 500V but not at 250, and would look open-circuit to the continuity test.

 

[Richard Burns]

Perhaps I should have said centre earthed filter capacitors and the like that cause low readings of resistance on power supplies.

 

[derbylad]

Hi All,

While carrying out a commercial EICR today, I was doing IR testing on one of the ring mains an was getting 0.00M ohms between L/N - and the earth bar at 250V & 500V (cant distinguish what 2 earth wires belongs to the other 4 cores)

I have continuity on both L & N legs which are acceptable.
Also tested L- E bar and N - E bar both giving me 0.00M ohms
carried out a resistance test for both L & N to E bar, one was 24.4 ohms and the other was 1034 ohms

No RCD protection at all. TN-S system.

Stumped.... any suggestions on coding and where to start looking for this would be greatly appreciated.

when you i.r tested at 250v and got an unsatisfactory reading why did you then test at 500v ?

 

[DPG]

Ok
1. 500V is the standard test voltage for pat testing, if anything can be damaged by 500V current limited to 1ma then it shouldn't be plugged in as it would fail the type testing
2. The output of a megger is current limited to about 1mA so it can't power anything.

The 500V from a PAT tester is applied with the live and neutral connected together, not applied between live and neutral. Daz