RCD's and RCBO's...Whats the difference you may ask?

[Spark123]

It is all pretty well explained here (16th edn document): http://www.theiet.org/publishing/wiring-regulations/mag/2005/15-insp-test-rcd.cfm?type=pdf

 

[ban-all-sheds]

Anyone who claims that a Residual current Circuit Breaker with integral Overcurrent protection is not a Residual Current Device is clearly an idiot.

The term "RCD" is not used to describe a device which provides overcurrent protection.

The fact that some residual current devices do provide it does not make it any more correct to say that "RCDs provide overcurrent protection" than it does to say "motorised vehicles provide comfortable seating for 50 adults" just because some do.

It is misleading and possibly unsafe to tell people that RCDs provide overcurrent protection when some don't, particularly when they are simply described as "RCD"s.

This says "RCD" on it:

It does not provide overcurrent protection.

An RCBO is a circuit breaker - would it therefore not be idiotic to say that circuit breakers provide residual current protection?

Given that this is a DIY forum, and we recently had a DIYer here who thought that a switch provided overcurrent protection because it had 100A written on it, maybe the idiots are the ones saying that RCDs provide overcurrent protection.

Edited to correct image URL

 

[Risteard]

No-one said RCDs provide overcurrent protection. They only said that certain types (RCBOs) do, which would be obvious to anyone who knows what RCBO stands for.

You are the one who says that incorrect usage of language should be challenged (e.g. electrocution) and yet here you are trying to defend abuse of the term RCD.

It is a generic term. Therefore I am challenging you on your misuse of it. An RCBO is an RCD which has integral overcurrent protection. That fact is not disputable.

 

[LoveRocket]

What on earth are you babbling on about Banal?

No one is saying that an RCCB provides overcurrent protection (other than the OP 6 years ago).

What we are saying is that an RCBO is an RCD.

 

[Spark123]

RCD is just a generic term
Even though the device in the MK piccy says RCD on it, the correct terminology for it is an RCCB - which is a form of RCD.

It is like looking in the regs at the term RCD and saying we must use a device with RCD printed on it, infact we can use RCBOs, RCCBs, SRCDs, current operated ELCBs etc.

 

[securespark]

Cor! If FWL were here, he'd be having a chuckle!

 

[ban-all-sheds]

Therefore anyone disagreeing with me that an RCBO is an RCD is frankly wrong.

Is anybody saying that an RCBO is not an RCD?

And as such, whilst it is not a function of an RCD to provide overcurrent protection it cannot be said that no RCD provides overcurrent protection.

No, it cannot, but since some RCDs do not provide overcurrent protection is just as equally cannot be said that RCDs do.

An RCBO most certainly IS an RCD.

But that does not mean that an RCD provides overcurrent protection.

An RCBO is an RCD and provides integral overcurrent protection, ergo certain types of RCD do provide overcurrent protection like I said.

And these, and other posts, by other people, seem to indicate a belief in them that it is not wrong to say that RCDs provide overcurrent protection.

It is.

 

[holmslaw]

What on earth are you babbling on about Banal?

He's just babbling, don't think he's had a mulipager for a few weeks this could be the biggest yet, a pedants paradise.

 

[Risteard]

And these, and other posts, by other people, seem to indicate a belief in them that it is not wrong to say that RCDs provide overcurrent protection.

No. I said that certain types (namely RCBOs) provide overcurrent protection. So it's not correct to say that no RCD provides overcurrent protection, although I have made clear on every occasion that it is not the RCD function providing it.

You're usually pedantic (don't worry - I like that) but you can't change definitions when it suits you. I can be more pedantic than anyone.

You fought well but you've lost this battle.

 

[ban-all-sheds]

I'm not trying to change any definitions.

Just, as I said, pushing back against the idea which seemed to be being promulgated which was that it is not wrong to say that residual current devices provide overcurrent protection.