Modules for old consumer unit

I have an Ashley SupaSafe consumer unit that has been in the house since it was built - about 25 years ago.

I’ve reason to believe that the RCCB is becoming unreliable and falsly tripping now and then.

Clearly you can’t get original parts (other than second hand) so windering whether it is possible to fit modern RCCB(RCD) and MCB modules or whether the whole consumer unit needs to be replaced.

I’m not against replacing the consumer unit but at the same time I imagine that woukd cost at least £400 and may not be necessary.

Cheers,

Nigel 

What makes you think it’s the Rcd that’s going faulty? When was the last time you had it tested? 

Sharpie makes a good point  Nigel ,  I'm guessing you are not an electrician  but something may be causing it to trip . ie:   It,s doing it's job.  

Ashley became part of Hager who  still trade so you may get an RCD to fit the board .  If you approach  an electrician many will tell you it needs to changed to a metal one  but thats easy to say when you're not paying the £400  . 

Just Googled ....the Ashley &Rock   Supersafe  RCD looks much like any other  , I would guess most RCD's would fit .   (  The powers that be don't like you fitting different makes  but its obsolete anyway , just do it )     Your board is PVC , don't worry about that either.  

I’m not sure I’d advise changing your RCD yourself, electricity is the silent but deadly killer and death is a cold and lonely place to be. 

I’d probably look for a local electrician perhaps ask a local wholesaler to ask for a recommendation. For how long it would take to both test and exchange and RCD your cost should be reasonable. 

nheather said:

I have an Ashley SupaSafe consumer unit that has been in the house since it was built - about 25 years ago.

I’ve reason to believe that the RCCB is becoming unreliable and falsly tripping now and then.

Clearly you can’t get original parts (other than second hand) so windering whether it is possible to fit modern RCCB(RCD) and MCB modules or whether the whole consumer unit needs to be replaced.

I’m not against replacing the consumer unit but at the same time I imagine that woukd cost at least £400 and may not be necessary.

Cheers,

Nigel 

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Unless you have done some appropriate testing of the wiring and the RCD, then I cannot see how you can come to your conclusion. It sounds to me, especially if the wiring is over 25 years old, that you could well have a wiring defect or an appliance defect that the RCD is correctly identifying and disconnecting the power to prevent an electric shock.

An RCD must disconnect the power in a very short time (less than half a second) and detect very small electric currents, (less than half an amp) as half an amp for half a second can kill a healthy adult. Domestic electrical wiring should be retested every 10 years. However this is industry good practice guidance not law.  The actual tests to verify if an RCD is operating within specification takes less than 10 minutes, (assuming you have got your tools already unloaded by the fuse box). Testing the circuit wiring takes longer, as dismantling of connections is required to isolate the circuit being tested from the rest of the installation.

If you have had no testing done in the past 10 years, I would suggest inspection and test of the circuits and fuse box equipment before you spend money replacing what may be a perfectly functional RCD, that is doing exactly what it is designed to do. If the installation has been tested you should have an A4 multi-page electrical certificate or inspection report, plus a label on the fuse box giving testing dates.  Faulty RCDs more often fail to operate at all because they have seized rather than suddenly becoming over-sensitive.

Doc H.

If you have only got one RCD on your whole fuse box....

AND its 25+ years old....

it may be best to just bite the bullet and get the thing upgraded anyway to a multiple RCD....  (Or preferably an individual RCBO per circuit),  system.

You could waste a fair bit of money faffing around swapping bits and still end up with a inconvenient arrangement that takes out multiple circuits when the RCD trips due to a fault on a single circuit..

Intermittent "random" RCD tripping can be signs of appliances such as fridge compressors, or central heating pumps/valves, damp in external wiring, rodent damage, and other such things failing..

A new multi-RCD board + full test on circuits would make it easier to track down a dodgy appliance problem...

RCDs do fail..

And I have replaced a few oversensitive ones over the years...  (I have been trading self employed now for just under 20years).

BUT,  at a rough guess 90%+ of these types of faults turn out to be wiring or appliance issues..

Less than 10% are actual RCD failing...

If I were a betting man I'd put my money on the RCD testing out all OK within its correct spec.

Guinness

Thanks for the replies.

I'm not opposed to getting a new CU but my fear is I pay £400 or more to get it replaced and the mysterious problem is still present.

Out of interest, how would an electrician go about identifying a problem that only happens every one or two days and the moment the RCD trips the fault is gone and the can be reset for another one or two days uninterrupted us?

I'm not an electrician but I understand electrical and electronic engineering and my thoughts are if it is all working at the time then any tests done would simply pass.

Cheers,

Nigel

The point is that so far you have proved nothing and just swapping a component that you have not confirmed to be fault will leave you none the wiser if or when the replacement RCD trips. As you mention you have knowledge of electronics and electrical engineering are you aware that your RCD must trip with a leakage current of 30ma but must not trip at 15ma. and there are specified times that the RCD must operate at when tested at 30ma and 150ma. These items can be easily tested with an approved RCD test meter. 30ma is a very small current eg. approx. 7watts worth of load , maybe the equivalent of the current needed to operate one LED lamp. So whether you do random swapping or actually carry out the industry recognised tests on the wiring you can at least prove that the RCD is not faulty and that there is no direct cable damage contributing towards your problem. The condition of the cables can be verified with continuity and insulation resistance tests as per guidance in BS7671 wiring regulations. Any installation with single RCD means when the RCD trips you don't even know which circuit(s) is or are causing the leakage current.

Doc H.

Yes  have to say,   as the Doc says ,    tracing your fault can be difficult as it occurs at odd times .    But still best to start with seeing if the RCD is stable  ,  then look at the circuits protected by that RCD  .  

An old RCD is less likely to trip than a new one, ergo soemthing is wrong, but as the tripping is intermittent I would suspect an appliance is developing a fault rather than a cct.

evidence of faults is usually there to be found, even if its not tripping at the time.

there is the odd occasion though where there is something showing but the actual fault is not there to be found, so its also possible to spend time looking at / fixing the wrong fault

I would suggest doing an itinerary of all items connected to power outlets on the day/time that the fault/trip occurs. Do this over a period of a week or two. This may give you an indicator, you could obviously reduce the number of items that are connected if they are not in use. 

nheather said:

Thanks for the replies.

I'm not opposed to getting a new CU but my fear is I pay £400 or more to get it replaced and the mysterious problem is still present.

Out of interest, how would an electrician go about identifying a problem that only happens every one or two days and the moment the RCD trips the fault is gone and the can be reset for another one or two days uninterrupted us?

I'm not an electrician but I understand electrical and electronic engineering and my thoughts are if it is all working at the time then any tests done would simply pass.

Cheers,

Nigel

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Is your RCD also a "Main Switch"? so the RCD is supplying the whole installation?

(If Yes;  how do you propose changing it with the incoming suppliers live cables connected to the input side?)

Or is the RCD only protecting part of the board so you also have some non-RCD circuits as well?

How many circuits are connected to this RCD?

Do you have any external wiring connected to this RCD, outdoor lights/sockets/water feature pumps etc....

Is the central heating connected via this RCD?  and if yes, are some of the central heating components also 25+ years old?

Have you had any electrical alterations done recently?  e.g. new socket or replacement socket front fitted or convert socket from standard to USB socket?

can you link / add a photo of your fuse box?

REMEBER: Until you track down the cause of this problem, replacing the whole board or just replacing an RCD you will still have the mysterious problem still there.

If the fuel gauge on my car is showing empty, the solution is not replacing the gauge, (as that will still show empty), it is filling up with fuel! 

The symptoms you describe don't sound like RCD failure to me....   The RCD is detecting an intermittent problem elsewhere... 

Where about are you ???  we may have a local forum member who could pop in to test your RCD and have a quick visual check around your installation.

:coffee

SPECIAL LOCATION said:

If the fuel gauge on my car is showing empty, the solution is not replacing the gauge, (as that will still show empty), it is filling up with fuel! 

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I wondered why I keep breaking down  :C