Minor cert main RCD replacement

[sparkdog]

What do you usually put on a minor cert regarding tests for main RCD replacement?Looks like Zs,insulation and RCD times would be about it.Also looks like it has been incorrectly wired from new with its neutral going to the non-RCD neutral bar but it is faulty,won't stay on with L & N on load side disconnected.Thanks.

 

[telectrix]

replacing an RCD is not MWC . you need a full EIC... test the existing RCD with it wired in correctly for starters. you need to measure your circuit parameters, including R!+R2. r1,r2,rN, fir ring finals. Zeand PSC.RCD trip times ( all 7 ) . check earthing and bonding and upgrade if necessary.

 

[IQ Electrical]

What do you usually put on a minor cert regarding tests for main RCD replacement?Looks like Zs,insulation and RCD times would be about it.Also looks like it has been incorrectly wired from new with its neutral going to the non-RCD neutral bar but it is faulty,won't stay on with L & N on load side disconnected.Thanks.

If the characteristics of the device are the same, I'd be happy with just the new disconnection times.

What IR and Zs will you measure, considering it's a 'main RCD' replacement?

Just to clarify after reading the post from Telectrix, because the RCD is not an overcurrent protective device, the only characteristics of the installation that you are changing are the disconnection times and they are only tested once (each test) at the device.

 

[telectrix]

reason im said EIC is because the RCD rfeplacement will affect several circuits.

 

[IQ Electrical]

Ok, think of it a different way: Are you altering the overcurrent protective devices that require a certain value of Zs to operate within a given time to comply with ADS?

The answer is 'no' so why would you get involved in the existing installation other than to visibly confirm earthing & bonding as you would before undertaking any work?

 

[Des 56]

Maybe a way to look at the situation is to ask yourself what difference does a change of Rcd make to the existing installation
Is, or are there,any circuit deficiencies that would result in you deciding that it was making the installation less safe ?

If you take the view that it is an improvement to change a faulty Rcd for a functioning one,then circuit readings have no added benefit

 

[Geoffsd]

Had similar before so agree with need for EIC but I would only consider testing up to the RCD is necessary; i.e. not the final circuits.

 

[telectrix]

agreed up to a point. IQ and Des. However, if, as he says, the old RCD is faulty. i would certainly IR all circuits, as the old RCD may not have picker up a fault.

 

[Geoffsd]

I would say so, GLENN.

As for tel's point - if new RCD doesn't trip would that not be ok?
Makes for a big job otherwise.

 

[IQ Electrical]

So ze pfc rcd times and earth bonds geoff?
Thanks.
Glenn.

Guys, you're swapping a main RCD, not doing a Periodic Inspection!

The only altered characteristics are the tripping times of the new device, I think we're forgetting that there is no overcurrent protection changing here....

By all means, you can complete an EIC (as you can for any minor works if you wish) but there would be no logical reason to do so.

 

[telectrix]

point conceded. LOL>