Looking for opinion on whether this scenario is compliant

[telectrix]

then the disconnection time is compliant (200mSec.).

 

[The Ghost]

Ok then I am worrying about nothing. Good.

 

[Strima]

Ok so what about table 41.1 TT?

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

 

[littlespark]

Keep at them about the broken sockets, and the day before they say they're coming, go back and replace with the old ones.
But then, youll be sitting with broken sockets in your shed for the next 4 years

 

[Adam W]

So everything is RCD protected and the CU was compliant when it was installed.
Cross bonding is no longer necessary.
The water and gas supplies should be bonded unless the pipes are plastic.

 

[Gavin John Hyde]

When you say council @Vortigern do you mean a housing association? if so and its curo you can contact the head honcho victor da cunha and he will actually personally respond to emails and deal with any issues like this! one of the few decent chief exec's i have come across, most of the housing associations around the west country are quite decent, Bristol council are one of the few in the region who still own there own properties, have done work for them.. they are slow paying and quibble over silly little things in the price and everything is as cheap as possible. Would not do contract work for them again.

 

[The Ghost]

do you mean a housing association

Mmmm not sure now you ask!

 

[The Ghost]

That’s for over current protective device disconnection

Yes thats fine so I am testing socket and get Zs of 11.75, compliant or no? (RFC 32A)

 

[Dillb]

Yes thats fine so I am testing socket and get Zs of 11.75, compliant or no? (RFC 32A)

You will usually get higher Zs values ok a TT than a T-N system. What is the Ra valie?

 

[westward10]

Frankie??

 

[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.