Low R2

[Malcolm]

Hi. I don't know if anyone can help or shed any light on this one.
I installed a new circuit in my sons garage. 2.5 T&E clipped direct, 4x metal clad sockets and back boxes.
I haven't terminated it into the CU yet as I need to get a RCBO.
I just got everything in place and did dead tests.

End to end L 0.21Ohm
N 0.21Ohm
E 0.02 Ohm

IR >1000 Mohm

There is nothing connected in the board so no parallel paths.
I had my yearly assesment today and I asked the assessor and he couldn't think of why it would be so low.
Any one any ideas?
Thanks

 

[Pete999]

Hi. I don't know if anyone can help or shed any light on this one.
I installed a new circuit in my sons garage. 2.5 T&E clipped direct, 4x metal clad sockets and back boxes.
I haven't terminated it into the CU yet as I need to get a RCBO.
I just got everything in place and did dead tests.

End to end L 0.21Ohm
N 0.21Ohm
E 0.02 Ohm

IR >1000 Mohm

There is nothing connected in the board so no parallel paths.
I had my yearly assesment today and I asked the assessor and he couldn't think of why it would be so low.
Any one any ideas?
Thanks

Poor connection on your MFT?

 

[Malcolm]

Nope. Checked it half a dozen times. same result. Checked it with my other mft, same result.

 

[hightower]

Excuse me for silly suggestion (just a trainee) but no parallel paths like cable armouring (I know you said T+E, just trying to have a go at helping) :willy_nilly:

 

[stevethesparks]

How far away is the CU from the sockets, and what are they fixed to?

 

[hightower]

What does the end to end test as on the rest of the unused cable drum?

 

[joehat]

Read the meter wrong?

 

[malcolmsanford]

They haven't put in a 10mm CPC in the T+E have they?

Honestly this defies logic. You obviously have a ring on your r1 rn and so by rights your smaller CPC should be higher on r2.

All I can think of it start to break the ring down, it's only 4 sockets and test the cable from CU to Socket 1 and then Socket 1 to 2 and go round the ring

 

[Malcolm]

Thanks for the replies.
(Hightower) No parallel paths. End to end on drum, I will try that. It was a new 100Mt roll.
(Steve) It's a double garage, the CU is in the garage. so total ring about 15/20mts? They are fixed to a breeze block wall.
(malcolm) Will do, I will be going back there next week to finish off, so I will try that.

 

[Pete999]

Thanks for the replies.
(Hightower) No parallel paths. End to end on drum, I will try that. It was a new 100Mt roll.
(Steve) It's a double garage, the CU is in the garage. so total ring about 15/20mts? They are fixed to a breeze block wall.
(malcolm) Will do, I will be going back there next week to finish off, so I will try that.

Metal sockets? if so remove the front plates from the back box and dis the fly lead (if you have one) and re test r2

 

[Malcolm]

Right just checked the rest of the roll.

L 0.37
N 0.37
E 0.67

Which is what you'd expect. So why it is down on the install I'm stummped.

 

[Malcolm]

Pete, yeah will try that also.

 

[Pete999]

Right just checked the rest of the roll.

L 0.37
N 0.37
E 0.67

Which is what you'd expect. So why it is down on the install I'm stummped.

Have you responded to post 10 yet?

 

[Malcolm]

Sorry wrote it out then got sidetracked.

Pete, yeah will try that also.

 

[Pete999]

Sorry wrote it out then got sidetracked.

Pete, yeah will try that also.

Please do I'm clutching at straws but I may be onto something