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Discuss No R1 on ring main? in the Periodic Inspection Reporting & Certification area at ElectriciansForums.net

C

Cirrus

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Wired a kitchen this week and the earthing system is TT with a 30mA RCD up front. Got round to testing and everything was going fine until I tried to test for R1. The reading I got was >2000 so basically showing open circuit. I have continuity and Zs but cannot seem to get my R1 +R2. I had this last week on a TT system and I know it can be calculated but can't work out why the Fluke MFT won't give me a reading when I don't get probs on any other earthing system such as TNCS / TNS. Is it just a fact that this happens with TT systems?
 
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Unregistered

  • Thread Starter Thread Starter
  • #2
sorry to pick faults but if its showing open circuit on R1 how have you got continiuty?
 
T

TonyM58

  • Thread Starter Thread Starter
  • #4
Cirrus,

ok my head is fried now

R1?

how do you measure R1? or why?:rolleyes:

R2 yes, R1+R2 yes, but R1????

like to help fella, but i think you would need to explain this test to me:)

the type of earthing system will only affect your Ze,Zs, PFC's and possibly your RCD times.

and a 30mA up front? oh dear, may as well throw the regs away:eek:
 
C

Cirrus

  • Thread Starter Thread Starter
  • #5
Sorry, was typing this on the way out so think I have screwed up what I was trying to explain. Will have a look at the test sheet and come back to you. As for 30mA up front - it is an existing crabtree starbreaker board. I have just added a new ring and cooker circuit.
 
T

TonyM58

  • Thread Starter Thread Starter
  • #6
when you say 'up front', is the RCd being used as the main isolator in the CU?

be interesting to know about the R1 thingy.......:rolleyes:
 
C

Cirrus

  • Thread Starter Thread Starter
  • #7
yes, the rcd is also the main switch. Board is probs about 20 years old but am now confusing myself and think that it is a 100mA rcd
 
T

TonyM58

  • Thread Starter Thread Starter
  • #8
if its the main switch then it should be a 100mA S-Type
 

ian.settle1

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Mentor
Arms
Cirrus,

ok my head is fried now

R1?

how do you measure R1? or why?:rolleyes:

R2 yes, R1+R2 yes, but R1????

like to help fella, but i think you would need to explain this test to me:)

the type of earthing system will only affect your Ze,Zs, PFC's and possibly your RCD times.

and a 30mA up front? oh dear, may as well throw the regs away:eek:
Tony

If it's a ring circuit then he has got to measure r1, r2 & rn for ring continuity.

Maybe he is getting mixed up with upper and lower case letters.
 
T

TonyM58

  • Thread Starter Thread Starter
  • #10
could well be Ian,

of course if its r1 and its open circuit, then this would epxlain why hes still getting Zs (although at an untrue value)

just shows that the three stage ring test works!

regards

Tony
 
C

Cirrus

  • Thread Starter Thread Starter
  • #11
Ok, sorted. I was using a plug top with a link between live and Earth and the link had come out. Now, what worries me is the boards. They are old crabtree boards. The main earth is 6mm and the boards have a 80Amp 30mA RCD up front. I know it is ideal to renew the board but the council won't pay unless it is Cat 1 and essential. Surely this isn't 'essential' as it just means that when the RCD trips, every circuit is affected.
Thoughts gents.......
 

ian.settle1

-
Mentor
Arms
Ok, sorted. I was using a plug top with a link between live and Earth and the link had come out. Now, what worries me is the boards. They are old crabtree boards. The main earth is 6mm and the boards have a 80Amp 30mA RCD up front. I know it is ideal to renew the board but the council won't pay unless it is Cat 1 and essential. Surely this isn't 'essential' as it just means that when the RCD trips, every circuit is affected.
Thoughts gents.......
And the council LABC are supposed to certify work is ok under Part P when notified..:rolleyes::rolleyes::rolleyes:

What a bloody good laugh sounds like do as I say but not as I do...:rolleyes::rolleyes::rolleyes:
 
T

TonyM58

  • Thread Starter Thread Starter
  • #13
Ok, sorted. I was using a plug top with a link between live and Earth and the link had come out. Now, what worries me is the boards. They are old crabtree boards. The main earth is 6mm and the boards have a 80Amp 30mA RCD up front. I know it is ideal to renew the board but the council won't pay unless it is Cat 1 and essential. Surely this isn't 'essential' as it just means that when the RCD trips, every circuit is affected.
Thoughts gents.......

Ok,

glad you got your readings sorted

bottom line is that this breaks a number of regs (16th edition). It depends if the council 'defines' what Cat I is. When an old dear falls down the stairs due loss of lights due to a spurious trip on an unrelated circuit, they may take notice, particularly if sued.......
 
C

Cirrus

  • Thread Starter Thread Starter
  • #14
I know Tony - so what do the regs state?
 
T

TonyM58

  • Thread Starter Thread Starter
  • #15
Ok, sorted. I was using a plug top with a link between live and Earth and the link had come out. Now, what worries me is the boards. They are old crabtree boards. The main earth is 6mm and the boards have a 80Amp 30mA RCD up front. I know it is ideal to renew the board but the council won't pay unless it is Cat 1 and essential. Surely this isn't 'essential' as it just means that when the RCD trips, every circuit is affected.
Thoughts gents.......
well it breaks a number of regs (16th edition) and is a safety matter if an old dear falls down the stairs due to loss of lights after a spurious fault on an unrelated circuit trips the RCD
 
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