Insulation Resistance / On site guide Ask questions and find answers to many subjects relating to electrics and electrical work

[s1bgs]

Hi all, just a quick Q re IR.
OSG 10.3.3 states `tests should be made @ DB with main sw off, all fuses in place, sw`s and mcb`s Closed meaning `ON`

Diagram 10.6 clearly says Main sw off, circuit breakers `OFF`.
To me `OFF means `OPEN` where as 10.6.6 says mcb`s should be `CLOSED` whhich to me means `ON`

any thoughts on this ? am I right in what i am saying?

cheers.

[kbrownie]

main isolation switch off/open
breakers/fuses in place, in on/closed position. I Don't have osg to hand so can't comment.
This is a dead test but still dangerous, certain equipment should be either removed or switches opened prior to test.
KB

[sparx]

Hi both, don't have osg in house but for in service inspection/test normal method is to have main switch open(off) so board effectively disconnected from mains.
All mcb's on /fuses in place, LINK Line to Neutral on dead (busbar) side of switch and test to main earth bar in con.unit.
If greater than 2 Meg no more tests should be needed and reading is noted on PIR sheet for all circuits.
If less than 2Meg then circuits must be individually tested by disconnecting neutrals and lines from mcbs, and joining as before & testing to earth with circuit cpc still connected to earth bar.
Doing it this way will protect any electronics from harm, if all sockets empty and no electronics on lighting ccts then lights switched off, Line to Neutrals can also be tested.
regards SPARX

[kbrownie]

Hi,
I have now had chance to look at osg. It is not a very good example but on close inspection it is correct. (obtical elution!)
KB