Andrew Gabriel wrote:
In article ,
Dave Osborne writes:
The Medway Handyman wrote:
Hi

Could someone clarify the difference between an RCD & a RCCD or is it just
different terminology?

There are various British and European Standards for the design of
electrical control gear. One of them (don't ask me which, I can't
remember) in about 1980 (possibly earlier - don't quote me) defined the
term RCD:-

RCD is an umbrella term to cover all Residual Current Devices.

It came about due to a campaign by Which? and That's Life!

Ah, I don't remember that. We didn't watch That's Life! or read Witch?
in our house.

This was the point where RCDs became consumer products, and
every manufacturer and IEE was calling them something different,

I don't remember that there were many different names. I remember that
there was confusion between old-style voltage-operated ELCBs (Earth
Leakage Circuit Breakers) and new-fangled current-operated ELCBs - which
became residual current circuit breakers.

leading to much consumer confusion and avoidance of the
products. Which? and That's Life! pressed the industry to
use one common name - RCD (which probably wasn't the best choice
but that's not important) - and the industry fell into line.

RCCB was one of the old names -- sort of hung on as some other
EU countries adopted it (even though it had no direct local
language meaning).

Hmm. I'm not sure that's true. More likely that the manufacturers made
product to UK spec. and then sold it on to whoever wanted it. Most of
the technical info printed on an RCD is symbolic not natural language
anyway, so each country would need its own crib sheet to interpret the
symbols. Easy to have a local translation of RCCB or RCD - or just
ignore it.


RCDs are sub-divided into RCCBs and RCBOs.

So, an RCCB is a Residual Current Circuit Breaker.

and an RCBO is a Residual current Current Breaker with Over-current
protection.

However, at that time, when the contracting industry and the IEE were
pushing the use of RCDs in domestic environments, there was very little
call for RCBOs (which hitherto were mainly used in factories).

RCBO's didn't appear until later -- until RCD's themselves
could be made small enough to make them worth combining with
an MCB, around 1990 from memory.

You may well be right on this point.

They were too pricey for
domestic use at that point though.


I don't think there was any call for them for domestic use and they
wouldn't have fitted in consumer units of the day anyway - you still
have to be careful to choose a consumer unit/RCBO combination that
physically works.


It's possible that the "standard definitions" were retrospective. I'm
pretty sure I've seen definitions as I have stated (in BS something or
other). I don't have wide access to BS any more, so I can't check
further. Perhaps someone can do some digging.