How to tell if a circuit is on an RCD?

[crt]

The lights are above the basin, either side of a mirror. The basin is more than 600mm to the side of the bath. The switch is way on the other side of the room, at least 3m from the bath.

Re the RCD circuits, does your answer mean that all the circuits in that CU are RCD protected?

 

[ban-all-sheds]

The lights are above the basin, either side of a mirror. The basin is more than 600mm to the side of the bath. The switch is way on the other side of the room, at least 3m from the bath.

No ceiling lights?

The basin may be outside the zones, but are both the lights?

Re the RCD circuits, does your answer mean that all the circuits in that CU are RCD protected?

Unless someone has done something bizarre with the split, and fed the far side of it from the other CU, then yes.

To confirm you could take the cover off and look, or you could try what's already been suggested:

Press the test button and see which circuits it knocks off!

Press the test button and see what goes off.

Push the test switch, see what happens.

 

[sparkiedave]

From the pictures, I didn't see a 6A breaker on the RCD side so unless your lights are on a 32A breaker or similar, they are not RCD protected, I would recomend fitting a RCBO for that circuit as the best way to solve your problem, and you would then have one more circuit which complies with 17th Edition

 

[crt]

So, to put an RCBO on the relevant circuit, I just get a RCBO cartridge of the right size and spec and slot it in to replace the existing device protecting the circuit??

Many thanks for all the input.

 

[Taylortwocities]

There is a bit more to it than that.

Firstly you must test the circuit to see if it is within the limits laid down
then you need to select the appropriate RCBO (usually it will be a B curve)

Then install the RCBO, test the EFLI and test the RCD at ½ 1x and 5x its rated tripping current and ascertain that it meets BS EN 61009-1.

 

[crt]

That all sounds very complex.

Probably easier just to bond to the light fitting earth and ensure all other metallic conductors are also bonded in the bathroom?

Basic question remains, though, why did the previous installers (electrical and plumbing) not bond if there is no RCD on the lighting circuit?

 

[ban-all-sheds]

From the pictures, I didn't see a 6A breaker on the RCD side

You must have a bigger screen and/or better eyes than me...

Probably easier just to bond to the light fitting earth and ensure all other metallic conductors are also bonded in the bathroom?

Do you want to?

Do you have any circuits supplying Class I or Class II equipment in Zones 1 or 2?

Basic question remains, though, why did the previous installers (electrical and plumbing) not bond if there is no RCD on the lighting circuit?

Because they are incompetent?

When was the work done?

 

[crt]

Do you want to?

It is not a massive job to do so as all the floors are up and the walls will need to be redecorated so filling in some chasing is not a problem. Cost of the g/y and bonding straps is inconsequential.

Do you have any circuits supplying Class I or Class II equipment in Zones 1 or 2?

No.

[/quote]Because they are incompetent?

Possibly, but all other aspects of the installations look to be done to a high standard, a recent electrical inspection didn't highlight any issue, and likewise recent work by a reliable plumber in the area didn't raise any issues.

When was the work done?

Within the last 10 years.

 

[ban-all-sheds]

It is not a massive job to do so as all the floors are up

If you're going to do it you can't hide the clamps under the floor - they are supposed to be accessible.

Do you have any circuits supplying Class I or Class II equipment in Zones 1 or 2?

No.

Then you don't need any supplementary equipotential bonding.

When was the work done?

Within the last 10 years.

If that means before June 2008, do you have any circuits supplying Class I or Class II equipment in what was Zones 3?

If so then bonding was a requirement.

 

[crt]

If you're going to do it you can't hide the clamps under the floor - they are supposed to be accessible

I was thinking more about running continuous g/y from the various bonding points under the floor, leaving the clamps visible.

Then you don't need any supplementary equipotential bonding.

Even if, as I suspect from the previous posts, my lighting circuit and equipment outside zones 1 and 2 is not RCD protected?

do you have any circuits supplying Class I or Class II equipment in what was Zones 3?

Only lighting which is caught as "luminaires" within the electrical equipment classifications I believe.

 

[ban-all-sheds]

1) Fair enough.

2) Yup.

3) And those luminaires will be Class I or Class II.

 

[crt]

Many thanks.

So, in summary, I did need it, and now I don't.

 

[ban-all-sheds]

Yup.

 

[Spark123]

Then you don't need any supplementary equipotential bonding.

I don't believe it is as cut and dry as this, to omit supplementary bonding you need to ensure all circuits of the location are RCD protected (17th edn), doesn't say just the zones.
You also need to ensure the extraneous conductive parts of the location are effectively bonded too.

 

[ban-all-sheds]

But you aren't relying on the RCD provision to omit bonding if no bonding is required because there's nothing electrical in Zones 1 or 2...