r2 reading

[c.boy]

Hi All,

Rewired a kitchen today and part of the downstairs ring, the old twin & earth is 2.5 and 1mm earth and obviously the new wiring 2.5 1.5 twin.Problem being, as i carried out the ring continuity test

live and neutral 0.32
earth 1.24???

As part of the ring is 1mm iam aware that i should be expecting a reading of 0.80 i checked all sockets and the d/b for any loose connections almost all of the sockets are brand new appart from 2 which look about 2-3 years old.

My boss is adamant that the readings should be bang on or just out!!having checked all sockets and d/b im stuck any ideas???

thanks

 

[Guest 004]

easy calculation of the earth is the resistance of the of P1 = 0.32 x 2.5/1.5 = 0.53 that is the reading you should be getting. As you are not you probably have 'unseen' connections in a joint box somewhere. The important thing to remember here is what the Zs of the circuit is, which in your case will be about 0.4 ohms + Ze, which will be acceptable. On the test sheet just put some comments about the readings (readings a little high on the earth)

If you are still unhappy, you will have to investigate further. If you have time

 

[nickblake]

probabley a loose connection or could be corrosion on a termanal or on the get carry out an R1&R2 test at each socket and see if you get any significat rises in the readings as you go round the sockets , its suprising the differance change any very old sockets on the circuit as these could also contribute too dirty terminals

 

[i=p/u]

well it shoulld be quarter of the loop as you probably know, and if higher could be a spur, and if keeps getting higher as you go along i think is reverse polarity.... someone will probably come with bang on awnser

 

[c.boy]

Hi

I have been under every inch off the floor and there is no j/b! i still have the d/b to change and ill recheck on monday
but as i said i checked that!as for 0.53 would i not be getting that if all the earth was 1.5?? as 0.32x1.67 =0.53 and 0.37x 2.5=0.8?
i will defo not get away with putting a note on the sheet as the boss is adament that everything should be spot on!! i have done a i/r test
and all is good! came across this a few times!! is he just being a ****?? a work for a large company and a think he wants to make a name for himself!!

 

[Guest 004]

So what are you r1r2 readings then?? have you done that? link the incoming phase, with the outgoing earth, then all your readings should be the same at each socket. Maybe that is what he talking about.

I think you will find that if it was 1.5 all the round the ring, then my calcs will be correct. It was how I was taught at college. As you have 1mm earth in places, its is of course going to make the reading higher.

 

[c.boy]

yes your calcs are correct as were mine!! as a said the entire ring is not all 1.5 and just wondered if any1 had come across this before!!! il change the d/b monday and obviously test more! ran out of time today.

 

[Guest 004]

I certainly dont think that your boss is a ****

 

[c.boy]

LOL !!!Thanks for your input but a dont think that all your readings can be spot on!!maybe you test from your van?? but a dont!!! and a also live in the real world!!!

 

[Guest 004]

Peace brother

 

[c.boy]

Dito dude

 

[telectrix]

c.boy. i take it that english is not your first language then?

 

[mayfair]

Hey Dude hows your cold man!!!!!

c.boy. i take it that english is not your first language then?

 

[i=p/u]

its scotch like half farmer and half monkey , ya na wa a mean pal. only joking

 

[telectrix]

cold is bad mate. needs alcohol.