Looking for opinion on whether this scenario is compliant

[The Ghost]

the Ra

Did not test Ra, just wanted to change sockets and get council to check basically.

 

[Gavin John Hyde]

What is the Ra valie?

If it is anything like the rods I have measured the last few weeks then the readings will be much higher than normal.

 

[telectrix]

That’s for over current protective device disconnection not RCDs.

Wrong..... if you look below table 41.1, it specifically mentions RCDs.

 

[Wilko]

Sorry if I've missed something, but B32 won't trip "instantly" with that L-N impedance. Hopefully appliances are protected by 13A fuses but a short in the cabling would cook for a while, I think.
And stepping out on the edge a bit further, I don't think the ring is intact

 

[The Ghost]

Ok so still, 11.7 ohms Zs on RFC any thoughts? 60898 MCB 32a B

 

[Strima]

Wrong..... if you look below table 41.1, it specifically mentions RCDs.

But if you rely on an RCD for fault protection you must ensure the fault currents are significantly higher than the rated residual current of the RCD.

As RCDs are used for additional protection then the timings for those must comply with table 3A in appendix 3.

Leaving you to ensure that the PSSC of the installation will disconnect the OCPD within the stated times of 41.1.

 

[Strima]

Ok so still, 11.7 ohms Zs on RFC any thoughts? 60898 MCB 32a B

Using a 30mA RCD for earth fault protection then your maximum permitted Zs is 1667 ohms.

But what was the PSSC for the circuit? Only this measurement will tell you if the OCPD will disconnect within 0.2 seconds.

For a 32 amp B type 60898 you need a current of 5x the device rating for a disconnection time between 0.1 and 5 seconds. i.e. 160 amps.

 

[Strima]

Infact looking at one of your earlier posts with you L>N of 2.64 ohms that will give you a fault current of 87 amps which will disconnect in roughly 40 seconds so it will not comply.

How far out in the sticks is her house and what was the voltage reading?

 

[telectrix]

agreed. the RCD will comply with a L-E fault, but not with L-N. for a L-N reading of 2.64, must be a bloody long circuit.

 

[westward10]

Doesn't need to comply across L/N as no values are given for this scenario. We need to know the L/N reading at source.