Earthing Reading

[paul_sut]

Hi all i did a fuse board change the other day and when testing i got a ZE reading of 0.43 and a KA of 5.93 why would the KA be so high, also zs failed on all circuits for breakers. This is TNS. what would any one recommend??

 

[paul_sut]

I just said on my post i was arranging a re visit for more investigation!!

 

[p11jor]

Your r1 + r2 reading looks wrong to me! Shouldn't it be around 0.23?

Wouldnt it go on the length of run?

 

[p11jor]

Wouldnt it go on the length of run?

Oh you mean the the line & earth together not the end to ends!!


Yer it's r1 + r2 / 4 iisnt it

 

[Richard]

Wouldnt it go on the length of run?

l=0.36 n=0.36 e=0.56

0.36 + 0.56 = 0.92

0.92/4 = 0.23 ohm

 

[Jimmy Boy]

Problem we have unlike the gas we don't have the power to turn off.

But you have the choice as to whether you should power it up, this whole thread worries me.

J

 

[Snapester]

Well no your readings should be 0.23 if you did a figure 8 at the board and tested at each point on the ring?
Something don't add up to me and you need to have good results and thorough tests to prove the main earth is at fault, especially if you are getting good readings of .43ohms with the Ze?

 

[Snapester]

:77: I have this feeling on this thread

 

[Jimmy Boy]

I think as for the ring reading, you should go to each point of use, and take the highest reading, now if there was a spur of a reasonable length off the ring the ohms would be higher on this than a pure ring and this would be the value entered on the cert as proof of meeting the disc time.

J

 

[p11jor]

l=0.36 n=0.36 e=0.56

0.36 + 0.56 = 0.92

0.92/4 = 0.23 ohm

Yer I put that underneath I miss read the first one!

 

[trev]

Your r1 + r2 reading looks wrong to me! Shouldn't it be around 0.23?

He's obviously not done the figure 8 .36+.56= .92 so he's added them together and put that down as (R1+R2)

 

[Octopus]

He's obviously not done the figure 8 .36+.56= .92 so he's added them together and put that down as (R1+R2)

Precisely what I was hinting at!

 

[trev]

You're too diplomatic today Murdoch

 

[p11jor]

But you have the choice as to whether you should power it up, this whole thread worries me.

J

With additional proTection by rcd is in place then 1667 ohms is the highest zs, we have 6ohms here, that's 1661 ohms less that the maxium.....although that is totally unrealistic zs and should be investigated but even then the regs states anything over 200ohms. So he has done everything to bs7671 here.

 

[Richard]

With additional proTection by rcd is in place then 1667 ohms is the highest zs, we have 6ohms here, that's 1661 ohms less that the maxium.....although that is totally unrealistic zs and should be investigated but even then the regs states anything over 200ohms. So he has done everything to bs7671 here.

Sorry in advance! Thats a poor attitude to take. I can honestly say that i'v never left an installation like that. Something is obviously wrong so it needs sorting end of.

 

[trev]

So he has done everything to bs7671 here.

Except testing it properly