# Testing an RCD



## Webby1 (Mar 11, 2012)

I posted a problem some time ago about the RCD test button not working.

One of the replies indicated that sometimes they "stick" and if I switch it on and off a couple of times the test button should then work..............which it did.

So now I always switch on and off at EHU and thought the problem was solved. But on trying a few days later the test button would not operate.......switch on and off and it works again.

SO............not knowing how the RCD works...............if the test button is not operating does that mean the whole unit is likely to fail when needed............................really I think I know the answer.......where might I look for a new unit..............are they ordinary household RCD units.

After some research I think I mean an RCBO.............but you already know that ?????????????

Thanks


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## cabby (May 14, 2005)

Yes we did already know that. :wink: 
Yes again to having it replaced. 8O 
Perhaps an electrician would be best, then if any problems you can inform your insurance company it was done by a trades person, you could buy the parts and ask your dealer to fit it for you.

cabby


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## Evs54 (Mar 11, 2013)

Webby1 said:


> I posted a problem some time ago about the RCD test button not working.
> 
> One of the replies indicated that sometimes they "stick" and if I switch it on and off a couple of times the test button should then work..............which it did.
> 
> ...


 An RCD usually protects the wholw board which probably is what you have, an RCBO usually protects a single circuit where an RCD is not used as a main switch. If the Rcd fails to trip on the test button it could be faulty or you have a poor earth circuit . . An Rcbo iusually identified with having a B or C before its current value ie B40. Rcd could be 63 /30 or similar. ITo test your system properly you need an Rcd tester and perhaps Loop impedance tester. And yes they are the same as what is used in domestic circuits.


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## Webby1 (Mar 11, 2012)

*RCD fault*

Thanks for your information EVS54...................from your description I think it is an RCD as it does indeed protect the whole circuit and is also the main switch.

The test button always works throwing the main switch hence my thinking it is a mechanical "stickiness" in the switch rather than a poor earth circuit...........which I think it would mean it would never work or randomly.

But you can see my lack of expertise so I'll get it properly tested/replaced asap and although it's easy to replace I take your point Cabby about potential insurance problems.

You don't think it could be caused by reversed polarity ????

Only joking ..................let's not go there[/img]


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## rayc (Jun 3, 2008)

*Re: RCD fault*



> Webby1 said:
> 
> 
> > Thanks for your information EVS54...................from your description I think it is an RCD as it does indeed protect the whole circuit and is also the main switch.
> ...


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## ubuntu1 (Jan 14, 2008)

*RCD*

Don't mess just get a motorhome engineer to fit you a new one. They aren't expensive but a real life saver if something goes wrong.


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## Evs54 (Mar 11, 2013)

*Re: RCD*



ubuntu1 said:


> Don't mess just get a motorhome engineer to fit you a new one. They aren't expensive but a real life saver if something goes wrong.


Rather recommend an Electrician .


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## ubuntu1 (Jan 14, 2008)

Why an electrician? I have had to sort out a number of motorhomes where a domestic electrician has done things that don't comply with the requirements of leisure vehicles. An Approved Workshop motorhome or caravan engineer will hold a 240v qualification specific to leisure vehicles.


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## cabby (May 14, 2005)

The point is it needs replacing and a qualified person to do it. Not a case of an easy job, as I said insurance company will require this, should there be a problem.A dealer should have a workforce to cover this.

cabby


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