quick test on a garage

[pevvers]

R1-0.32
rn-0.32
R2-0.48
R1+R2-0.48

now my questions i thought R1,R2 was meant to be a quarter of R1+R2?
on the insulation test did i get a dead short due to earth and neutral having the same potential?
any help would be great

Well the calculation on a ring would work out at (r1+r2)/4, but if you have done the figure of 8 test then this could have been due to spurs. If the figure of 8 test was conducted the other way around, you could get spurious results.

The live neutral fault could be due to the main switch not being open. If this is the case, then you would be seeing the neutral-earth link the PME head if it's TN-C-S, or back at the star point of the transformer if it's TN-S.

Make sure you've isolated from the main switch, and left all MCB's on and fuses in place....

 

[Mr Mark Sparks]

Well the calculation on a ring would work out at (r1+r2)/4, but if you have done the figure of 8 test then this could have been due to spurs. If the figure of 8 test was conducted the other way around, you could get spurious results.

The live neutral fault could be due to the main switch not being open. If this is the case, then you would be seeing the neutral-earth link the PME head if it's TN-C-S, or back at the star point of the transformer if it's TN-S.

Make sure you've isolated from the main switch, and left all MCB's on and fuses in place....

for anyone like me who didnt know what spurious was

–adjective1.not genuine, authentic, or true; not from the claimed, pretended, or proper source; counterfeit.

 

[pevvers]

for anyone like me who didnt know what spurious was

–adjective1.not genuine, authentic, or true; not from the claimed, pretended, or proper source; counterfeit.

Sorry, should I just have said incorrect results?

My bad,

 

[Guest123]

for anyone like me who didnt know what spurious was

–adjective1.not genuine, authentic, or true; not from the claimed, pretended, or proper source; counterfeit.

lol.....:d

 

[Mr Mark Sparks]

its ok its my new word i will put it somewhere on my next periodic to confuse my manager

 

[pevvers]

Just pointed this out to the missus, and she doesn't know what it means either... So you're not alone!!

That'll teach me for reading the "improve your word power" section of Readers Digest in the bog for the last 25 years or so,

 

[Guest123]

I prefer to substitute the word spurious with "a bit iffy"

 

[jimmylaud]

thanks for all the replys so basically what i should have done was disconnected the ring from the board and then done the insulation tests? What do you mean by figure of 8 test pevvers? Has anyone got any thoughts on why my R1+R2 was higher than it should be thanks again

 

[Johno]

the R1+R2, if all sockets was on the ring,you would expect to be about 0.2 but if there was a spur off the ring then that would be added which would give a higher reading

 

[Johno]

as for the insulation resistance, if you are testing 1 circuit only, you must disconnect it, (L,N+E) and of course disconnect/unplug any appliances and remove any bulbs etc, but i find it is a good idea to test at 250v, to make sure nothing is still connected, before doing 500v