531.3.3 & Maintenance

[lozarus]

As we know, Type A RCD's are favourite for many circuits (in terms of Socket outlets, lights etc)

At our site most of our lighting is now LED - we've been swapping them out as a combination of upgrade and just remedial works. However, as they're all on Klik roses we haven't had anything to do with the boards - so the circuits are still sat on their AC RCD's.

At what point does one have to 'decide' that the DC currents will blind an AC and I need to change the existing RCD's to A?

In my eyes the job is "maintenance" - but at the same time we haven't really "replaced like for like" - as we don't fit fluorescents anymore.

This made me wonder how domestic folks approach this. For example, - if you change Mrs Smiths 8ft fluorescent in her kitchen because it has failed or she wants something brighter, is that enough to tell her it can't be done unless a Type A is retrofitted to replace her old AC one?

It's frustrating that there's no figures given for acceptable DC leakage. Leaves it a bit vague surely?

 

[Pretty Mouth]

My opinion: replacing lights, accessories, etc is maintenance, so I wouldn't upgrade the RCD.

Also my opinion: I doubt DC blinding of AC RCDs is that commonplace, and most of the AC's that I have tested have passed a test on A setting anyway.

 

[James]

You have made a really interesting point.

If you have changed something for maintenance then a like for like replacement needs no further thoughts or considerations.

however, if it is not a true like for like replacement then due consideration should be given to how it affects the circuit protective devices.

a similar but slightly more obvious one would be replacing light switches with fancy metal faced ones when there is no cpc available at the switch point.

there is no simple answer other than we should consider how the changes we make to any circuit affect its safety and not just blindly follow a reg. that we think should cover our behind.
lets face it, if the changes we make reduce the safety and someone gets hurt, we could end up spending some time in court and nobody wants to be in that position.

 

[newfutile]

Do an rcd test with the lights on,try on type AC with lights on,you could also do a type A test to see if you can blind the device,you then have information to make a decision

 

[littlespark]

I would think it’s not just LED lights.
Anything with a DC element could have an effect.

Maybe one for the powers that be to answer… ie, the authors of the regs.