RCCB not tripping

In the process of installing a new Consumer unit. (Contactum 10way split load) Just got power and the main earth (6mm earth from incomming cable lead sheath to be replaced later by PME) connection onto it at the moment but the test button on the RCCB (30mA) does not cause it to trip. Anyone know of any reason, other than it's DUFF, for it not to function ?

thanks Ady

Reply to
ac1951
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If it calls itself an RCCB it's probably pretty ancient. Yes if it doesn't self-test it's faulty, at least per the regs. It *could* be that the test circuit is faulty - you'd have to test it with an RCD tester (or suitable resistor from live to earth) but either way it's not for production use.

Reply to
John Stumbles

You don't need an earth for the test button on the RCCB to operate, as the test button creates a current imbalance between the "input" side and the "output" side of the RCCB. Usually, if the RCCB does not trip on the test button, it will not trip on a "proper" earth fault either. This is because the little itty bitty (technical term ;-) ) solenoid is "stuck" and will not trip the mechanism on the available fault current. It's duff; Send it back for a replacement.

HTH Rumble

Reply to
Dave Osborne

Nah, RCCB is the proper term. RCD is actually an umbrella term which includes RCCBs and RCBOs, but the industry is inconsistent in its use of the terminology. ISTM you're thinking of an ELCB, which would be ancient.

Category: RCD (Residual Current Device) Sub-Category: RCCB (Residual Current Circuit Breaker) Sub-Category: RCBO (Residual Current Breaker with Overcurrent protection) ELCB: Earth Leakage Circuit Breaker (Obsolete terminology for obsolete technology).

Cheers,

Rumble

Reply to
Dave Osborne

True, and EN 61008-1 does refer to RCCBs, but UK market devices have long since been labelled "RCD" (or "RCBO") and not "RCCB". I think it's an industry agreement to simplify the message for the general public.

John's words "calls itself an RCCB" were significant since one that does is probably be quite old and to the old BS 4293 standard. In mentioning ELCBs you've introduced a red herring - I see nothing to suggest that it's one of those.

Reply to
Andy Wade

Its faulty, replace it.

If for some reason you want to mess with it, you could add an external test button, which is a push to make button + a resistor that passes

30mA. Connect from live in to neutral out, and test using that. If it trips on that test it will trip on a real world fault ok, if not its stuffed.

NT

Reply to
meow2222

Well, ABB, MEM, Siemens, Moeller, Merlin Gerin, Crabtree, Square D and Hager (to name but eight) all know what an RCCB is, and some even label their product accordingly.

e.g.

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the reason there is confusion over the nomenclature is simply because Wylex and MK marketing people don't know the difference.

In introducing the term ELCB I have not introduced a red herring at all. I'm not suggesting for a moment that the op's device is an ELCB, I was merely trying to show where Mr Stumbles may have been barking up the wrong tree.

Cheers, Rumble

Reply to
Dave Osborne

Fair enough.

As I said, I think it's deliberate rather than done out of ignorance. The term "RCB" was also used at one time.

Reply to
Andy Wade

Either its knackerd, or you have not actually got power going to it yet...

(would not be the first time I had a new out of the box split load CU with the internal bus wires in the wrong places (one would have shorted the main supply if installed as supplied!))

Reply to
John Rumm

That reminds me of a story involving a generator transfer switch, two

300 amp fuses and a somewhat red-faced electrician. . .
Reply to
Andy Wade

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I checked the internal wiring before installing the CU and can confirm it's wired correctly (but thanks for the advice) Regarding RCD or RCCD, I was aware of the confussion but in posting I decided to follow the naming convention used by Contactum and also as advertised (currently) on TLC's web site.

I've arranged for a replacement to be shipped from TLC and will post again on that experience (hopefully no issues)

Thanks to all for the advice..

Andy

Reply to
ac1951

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OOPS didn't mean to introduce more confussion I did mean to say RCB and RCCB (must wake-up before making early morning posts :-)

Reply to
ac1951

Just to add to the confusion, what we now know as RCD's were commonly referred to as "current operated ELCB's" in their early days. That's certainly the case in the 1979 MK catalogue I still have.

Reply to
Mike Clarke

or even RCD and RCCB ;-)

Reply to
John Rumm

ELCB covered both types: "current operated ELCB's" are what we now call RCDs as you say, "voltage operated ELCB's" are the older ones with two separate earth terminals which monitor the voltage between the CPC and real ground.

RCD comes from a campaign by Which? and That's Life! to get the industry to agree on a common name. When these started appearing as consumer products (initially in the form of 13A plug-in types), every manufacturer started calling them something different, which made it impossible for consumer organisations to talk meaningfully about the devices and their safety advantages. Which? and That's Life! got together with the industry and persauded the industry to adopt a single term name, and the industry decided on RCD.

Reply to
Andrew Gabriel

Unfortunately, that's not universally true. There are some that generate an earth leakage by the test button, and cause upstream tripping too. There are some that have a monitoring earth connection and will deliberately fail a test if it's not connected, even though they don't use it to generate the differential test current. Some use their earth connection to operate the trip mechanism if the neutral becomes disconnected, which will also trip upstream.

They contain electronic circuitry which can cease working too. Had that with a powerbreaker one.

Reply to
Andrew Gabriel

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