Split load CU

[Doctor Drivel]

That means very few bathroom would ever have them fitted.

[Doctor Drivel]

What are you saying?

[Andy Hall]

That RCBOs are not well suited to protecting lighting circuits anyway for obvious reasons.

[Andy Wade]

And these obvious reasons are ... [not obvious to me]?

[Doctor Drivel]

Gasp! an echo!

[Doctor Drivel]

State it twice and it becomes obvious.

[John Rumm]

The smallest trip current RCBOs commonly available are 16A ones. This exceeds the current carrying capacity of 1mm^2 T&E, and also the rating of many lamp fittings. Hence you would needs additional fusing etc. THis kind of defeats the point of the RCBO.

A 30mA trip RCD spur on a conventionally protected 6A lighting circuit is a more elegant solution at little (say £15 - £20) extra cost. As someone else highlighted you will save that on not needing to EQ bond the bathroom.

For bathrooms that have other higher current using appliances (wall heaters etc), then the RCBO solution may be workable with a RCBO protecting the higher capacity circuit and a FCU used to feed the lighting circuits.

[Doctor Drivel]

The 17th will say that RCD on all bathroom lights, unless way high. So just having the lights on an FCU will not comply.

[Andy Wade]

? - There's no problem finding 6 A and 10 A RCBOs. E.g. MK Sentry range

6932s: RCBO B6 / 30 mA, 230 V, single pole, solid neutral, M6, Cat 3.

[John Rumm]

Which is why I said *commonly* available. Most places don't seem to carry anything below 10A, and even those are not always available (16A often being the smallest that many offer). Even TLC only have a couple of 10A choices and no 6A ones.

(RS do them, if you don't mind taking out a second mortgage to buy them!)

Obviously this will change with demand, but compared to the half cost option of a local RCD spur without the need for a dedicated cable run, I can't see the RCBO option catching on for installations that just require one room with RCD protected lighting.

[John Rumm]

Yes it would, if the circuit has a RCBO at the head end.

e.g. Bathroom has a 16A radial circuit to feed a wall mounted fan heater. This could be protected at the CU with a 16A type B/30mA trip RCBO, and then the bathroom lighting could be powered via a 5A FCU on the same radial.

[Doctor Drivel]

The 17th. The bathroom is easy enough, have RCD protection on all electrical fitting in the bathroom and equipotent bonding is not required. How does the 17th address equipotential bonding/RCD in the kitchen?

[Doctor Drivel]

It's easy when you say it properly isn't it?

[ARWadsworth]

Which is fine if you have a MK CU.

Most people have what the electrician fitted.

Adam

[John Rumm]

What are you on about?

[John Rumm]

yes, we were discussing the detail of implementation, not the broad concepts.

Same as 16th mostly. EQ bonding is not required in a kitchen as before.

RCD protection on general purpose socket circuits. Any non protected sockets need to be specifically labelled.

(with the 16th edition the RCD protection of the sockets was not a requirement unless there was a likelihood they may be used to power portable equipment outside. However it was common practice to protect them thus anyway, and in many cases there was a good probability they would be used for powering appliances outside so it was often a requirement)

[John Rumm]

RS also list a few other makes like Siemens and Merlin Gerin which do not seem to be that commonly used. There was a Hager one mind you (still at £65 though!)

[Owain]

This is not just an RCBO. This is a Hager RCBO sold by RS ...

Owain

[Doctor Drivel]

That's what he said! There something wrong with the Jocks today.

[John Rumm]

Individually selected for freshness, and hand wrapped in an organic box by nubile virgins....

(which when you compare to the bog standard Hager RCDs at £12, and MCBs at £6 (admittedly lobbed into a box by a bloke called Dave in Basidon) does make you wonder).