Discuss Exceeding max adjusted Zs on a board change. in the Electrical Forum area at ElectriciansForums.net

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polo1

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Testing during a board change, a RFC on a 32A 60898, with rcd protection, you find that the max Zs is exceeded by 0.1 ohms using the no trip setting on your mf tester
On the EIC do you -
A) simply record the actual measured value
B) record the actual measured value and note the position under comments on the installation
C) retest, bypassing the rcd, on the Hi setting of the tester and record the revised value
D) change the ocpd to a lower value to achieve compliance with max Zs
E) do something different?

There's a round of drinks riding on this, so think carefully!
 
It is a board change so not much you can do about the Zs so use the rcd for fault protection.
 
It would have to be a very long RFC to have a non compliant Zs on a B32 Mcb, I suspect a high resistance connection lurking somewhere.
 
Don't understand why the Zs is so high with those readings, ditch the rcd and test on high.
 
The R1 & R2 must have been obtained at a spur on the RFC ? Regardless you have a Zs of 0.79 which is well under the max value for a 32a B type OCPD ?
 
The R1 & R2 must have been obtained at a spur on the RFC ? Regardless you have a Zs of 0.79 which is well under the max value for a 32a B type OCPD ?
This is what I worked out to max to bs7671 on ocpd is 1.37 O.P. said +0.1 that gives 1.47 ????????? even at 80% I make it 1.09 + 0.1 =1.19
 
Test a few more times and take the best reading. Tin hat on and suitably bonded to the nearest window frame/radiator :)
Daz
 

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