Why "No RCD protection on lighting circuit"?

[EFLImpudence]

Appliances never require RCD protection. ... It is the cable which may require it.

I'm not so sure about that. For a long time there has been a requirement for RCD protection of a socket likely to supply an 'outdoor appliance',

The socket must be protected by an RCD in case you damage/cut the cable.
(sockets are not appliances)

even when the same circuit, with the same cable would not have required RCD protection if there were no socket likely to be used for outdoor equipment.

?

Similarly with the requirements we now have for RCD protection of any circuit supplying a bathroom - again, it's not really the cable that is being protected, but, rather, whatever the cable is connected to.

No. It is the people who are being protected.

As we have said before, an electric shower does not need RCD protection; the circuit does for benefit of the person.

 

[JohnW2]

The socket must be protected by an RCD in case you damage/cut the cable.
(sockets are not appliances)

... or in case exposed-c-ps of the equipment/appliance/whatever were somehow to become live.

even when the same circuit, with the same cable would not have required RCD protection if there were no socket likely to be used for outdoor equipment.

?

There may have been some misunderstanding here - I thought you were talking about the cable of the fixed wiring of the circuit, not the flex of the 'appliance'. However, your reference below to a shower confuses me even more, since that only has 'fixed wiring'.

Similarly with the requirements we now have for RCD protection of any circuit supplying a bathroom - again, it's not really the cable that is being protected, but, rather, whatever the cable is connected to.

No. It is the people who are being protected.

Quite - it's not primarily the cable that is being protected but, rather, what the cable might be connected to (like a person!).

As we have said before, an electric shower does not need RCD protection; the circuit does for benefit of the person.

Again agreed - but protection for whatever was connected to the end of the cable (like a person), not (as you said) to "protect the cable".

Kind Regards, John

 

[EFLImpudence]

John, I know you like a good discussion but there comes a time when it looks like you just question everything for the sake of it.

You will not find an appliance where the instructions (correctly) state that "This {whatever} must be protected by an RCD".
You know perfectly well that <50mm. buried cables must be protected by an RCD in case someone screws/drills into them.

It is not the shower which must have RCD protection.

 

[DetlefSchmitz]

John, I know you like a good discussion but there comes a time when it looks like you just question everything for the sake of it.

You will not find an appliance where the instructions (correctly) state that "This {whatever} must be protected by an RCD".
You know perfectly well that <50mm. buried cables must be protected by an RCD in case someone screws/drills into them.

It is not the shower which must have RCD protection.

The shower fitting instructions will be almost guaranteed to require an RCD. This is firstly to protect the shower vendor (legally), and secondly to protect the shower user.

 

[JohnW2]

The shower fitting instructions will be almost guaranteed to require an RCD. This is firstly to protect the shower vendor (legally), and secondly to protect the shower user.

I know - but it was EFLI who brought showers into this discussion, not me!

Kind Regards, John

 

[EFLImpudence]

The shower fitting instructions will be almost guaranteed to require an RCD.

Yes, for the circuit.

This is firstly to protect the shower vendor (legally),

They will state it because that is what the electrical regulations require because it is in a bath/shower room and the pipe may be exposed.
Some have metal hoses to the rose - an unnecessary hazard.

and secondly to protect the shower user.

Yes, although it is difficult to see how a plastic appliance can present a hazard.


The shower itself does not benefit from RCD protection.

 

[EFLImpudence]

The shower fitting instructions will be almost guaranteed to require an RCD. This is firstly to protect the shower vendor (legally), and secondly to protect the shower user.

I know - but it was EFLI who brought showers into this discussion, not me!

That is why Detlef quoted my post.

 

[JohnW2]

You know perfectly well that <50mm. buried cables must be protected by an RCD in case someone screws/drills into them.

Indeed but, at least in a TN system, not really to "protect the cable" - it's in case someone touches the screw or nail. ... and, in any event, the requirement for RCD protection of any circuit supplying a bathroom would still be there even if the whole cable run were protected (from nails/drills) by conduit with half inch thick steel walls - so clearly is nothing to do with the cable, per se.

Kind Regards, John

 

[EFLImpudence]

You're quibbling.

"...the cable shall be provided with additional protection by means of an RCD..."

Goodness knows what that really means.

 

[JohnW2]

You're quibbling.

I suppose I am - but only really because I responded to your initial "quibble"....

Appliances never require RCD protection. ... It is the cable which may require it.

Kind Regards, John

 

[sparkwright]

But the whole of the shower circuit doesn't need to be protected though, does it?

There's no reason why a non-RCD-protected surface mounted cable couldn't be run from the cu to the corridor just outside the bathroom, then to an RCD, then into the bathroom, via pull cord perhaps, to the shower.

 

[JohnW2]

But the whole of the shower circuit doesn't need to be protected though, does it? There's no reason why a non-RCD-protected surface mounted cable couldn't be run from the cu to the corridor just outside the bathroom, then to an RCD, then into the bathroom, via pull cord perhaps, to the shower.

Indeed not (that is, after all, a fairly common situation) - provided, of course that the cable is not 'new' and requiring RCD protection itself because it is buried <50mm deep in a wall.

Kind Regards, John

 

[EFLImpudence]

I didn't have time nor think it necessary to quote all of Chapter 52.

 

[bazme]

Ah - light dawns. I put all my trust in the almighty CU god and now I see it is not infallible. So I have three lighting circuits without RCD protection. To do the job properly I now need 3 RCBOs to replace the 3 MCBs on the right of the CU. Can anybody please point me in the direction of a supplier of NSB type RCBOs that are interchangable with the MCBs? The cables are <50mm where they enter the switches - so the inspector is right!

No overcurrent protection on Circuit 8 arose because the sockets were originally on a ring circuit with a 32A MCB. I split it into 2 radials but did not drop the MCB to 20A. I am putting the two radials on 2 seperate 16A MCBs.

 

[AndyPRK]

You only need rcd protection on the light circuits in the extension.

Rcbos are £35 each? And it's quite an old board so I would only go for 1