Can RCD's be faulty

[Doc Hudson]

All this has doe id proved it isn;t a faulty appliance. It is now either a wiring fault or faulty RCD. I've never replaced a faulty RCD, I've been called out to many wiring faults. I think you are wsting your money changing the RCD, and (no offence intended) I don;t think you should be changing the RCD yourself as it's not just a case of plugging it in. I'm not saying you are incompetent, just that I'm here, you're there, erring on the side of caution here.

Thank you Lurch. You are confirming the general consensus of this thread, that it is best to get correct testing done by a competent person before replace anything. The comment in your first paragraph probably hits the nail on the head? "I've never replaced a faulty RCD, I've been called out to many wiring faults."

Doc H.

 

[Andy™]

Thank you Lurch. You are confirming the general consensus of this thread, that it is best to get correct testing done by a competent person before replace anything. The comment in your first paragraph probably hits the nail on the head? "I've never replaced a faulty RCD, I've been called out to many wiring faults."Doc H.

ive had the odd faulty RCD, but almost everytime it is faulty wiring and not RCD

 

[NozSpark]

I can only confirm Lurches and Andy's posts..

The only faults that I have found with RCD's are when they don't trip when tested...

I have never been to any RCD that trips without any underling circuit fault..

 

[jdmjrmdam]

What would cause a fault like this to suddenly manifest itself? Could it be rodents chewing a cable?

 

[Lurch]

Could be anything, rodents, damp, corrosion, pressure on a cable in a box, cable disturbed somewhere, anything really.

 

[Andy™]

often dampness, but can be many other things inc rodents

 

[NozSpark]

Damp, slugs, water getting into light fittings, rodents, mechanical movement, crushed cables, heat from pipes, loose connections, DIY that never hapened (nails, screws, drills...)

all sorts of things

 

[paul b b]

What would cause a fault like this to suddenly manifest itself? Could it be rodents chewing a cable?

thats quite possible!

also remember that cables do vibrate, thus possible to work themselves loose if a connection is not properly tight.

or maybe something has melted together due to poor connection or diy job gone wrong.

paul

 

[batty]

Could be central heating if you have it and ovens are another favorite also immersion heaters. I would isolate these to start with. As others have said it is unlikely to be RCD although that its not to say it could not be. If RCD will not reset it's easier to find than nusaince tripping which is a lot harder to find. Welcome to the forum by the way.

Batty

 

[davetheglitz]

I've been called out over this cold snap and found lots of condensation in lofts, and in one particular case drips onto an aerial amplifier. This was double insulated - but the plug was conventional and had the cardboard connection details on the back. When this got wet it was enough to cause an RCBO to trip after a minute.

In 4 years I've only had one RCD failure - but loads of circuit and appliance faults. First rule is unplug and isolate everything in sight and see if things improve!

If not call someone with the test gear to check it out!

 

[SPECIAL LOCATION]

What would cause a fault like this to suddenly manifest itself? Could it be rodents chewing a cable?

In addition to the other replys... rodents / damp etc..

(don't forget washings machines & dishwashers are very good a generating damp around electrics!)

As we are having a bit of a cold and damp spell at the momenent...

and its Christmas / new years hols....

Possibly there are more people in a property for longer periods of the day consuming more lectwickery.... and remember...

ELECTRICITY ALWAYS GENERATES HEAT when passing through a circuit!

could be just something got a bit warmer than normal... melted a bit of insulation around a badly terminated accessory / j-box.

there can be lots of valid reasons for a fault to manifest itself.

:|

 

[SPECIAL LOCATION]

But can a fusebox and its internal bits be called like for like?Doc H.

Unlike an MCB which has a max permissable Zs, an RCD's characteristics are not relevant to the lenght of the circuit.

Just the mA trip rating e.g. 30mA, 100mA.....

Time delayed or standard operation.

Max current rating, e.g. 25A, 60A, 80A, 100A......

so IMHO as long as the new RCD is the same rating characteristics...

& spec (BS EN 61008) then it would be Like - 4 - Like!

Whereas a complete Fuse box replacement cannot be considered as like for like as per note 'C' page 8 Approved document P.

 

[gselectrical]

All this has doe id proved it isn;t a faulty appliance. It is now either a wiring fault or faulty RCD. I've never replaced a faulty RCD, I've been called out to many wiring faults. I think you are wsting your money changing the RCD, and (no offence intended) I don;t think you should be changing the RCD yourself as it's not just a case of plugging it in. I'm not saying you are incompetent, just that I'm here, you're there, erring on the side of caution here.

Ive replaced many faulty RCD's. Mostly on caravan parks though, where damp is an issue. :Y

 

[SPECIAL LOCATION]

Ive replaced many faulty RCD's. Mostly on caravan parks though, where damp is an issue. :Y

Valid point there GS!

environmental issues can affect the switch gear!

spose the other question thats not been asked is..

was the quarterly test-button test done as per BS7671 & manufactures guidance? :| ?:|

 

[sellers]

I would definatley get an electrician in to have a look. Your looking at 'roughly' 30quid per hour and may only take 1 hour to actually locate the problem (first hour will probably be a little more). You wouldn't mind paying someone 30quid to take a look at why your car won't start.

As for changing the RCD this would have to be done by a part p registered electrician. You are allowed to change items like for like. But within a consumer unit its a bit more technical, with certain ratings, bs numbers etc to be followed along with tests afterwards. I don't agree with the 'like for like' scenario within a consumer unit.

You don't want to swap your rcd, find it works and doesnt trip, then years down the line get a shock from the original wiring fault and find the new rcd was broken and staying closed due to not testing it with the correct equipment.

Right off to bed, had a few too many Guinness but it is xmas

 

[AFB1]

Many thanks to everyone who has answered. I have just managed to locate an electrician who is coming round this afternoon.

Will let you know the outcome later.

Kind regards

Tony

 

[Apache]

Many thanks to everyone who has answered. I have just managed to locate an electrician who is coming round this afternoon.Will let you know the outcome later.

Kind regards

Tony

Good man!

Have a beer while you are waiting! Guinness

 

[ianmacd]

No paperwork if like for like *runs and hides*

No paperwork to BC not no paperwork at all. Should still have a MWC (to record new RCD times).

Ian.

 

[matt.leung]

i would always paper work a job, even if it just for my own records....

for this electrical job i would def complete the correct paper work

 

[ianmacd]

i would always paper work a job, even if it just for my own records.... for this electrical job i would def complete the correct paper work

So now comes the question, MWC or EIC?.

I would do a MWC but scams may want you to test all the circuits protected by the RCD but (as mentioned above) its a supplimentry protection device not the main one and they are not changing (unless you cant find an RCD that fits and a new board is required).

Ian.