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Different rcd manufacturers

I've been told that I have a faulty RCD in my consumer unit. But I'm having a job getting a hold of the same manufacturers replacement. A mate has told me that doesn't matter as I can get a hold of any provided it matches the same spec - is he right?

4 Answers from MyBuilder Electricians

Best Answer

Not strictly speaking no. Whilst a lot of RCD's and MCB's are interchangeable and will fit, the original manufacturers brand should be fitted if at all possible.

When manufacturers submit their products for type testing, approval and certification before they go on sale, they are only ever tested with their own products. So whilst another make of RCD will fit and would likely to perform ok, technically the complete assembly has not been type tested and approved for differnt brands of product working together. Therefore if there was ever an issue later, say a fire etc, then your household insurance may not pay out if this came to light?

Whilst its rare/unlikely that you would have a problem in the future there has been a few articles on this particular issue as its quite common to find mixed makes of MCB and RCD in consumer units. Both articales in Professional Electrician and Wiring matters (IET magazine) strongly advise against doing this, so best bet is to try and speak to the manufacturer to see if they can tell you of a local stockist.

What make of RCD is it?


Answered 18th Jul 2012

Your friend is correct in that as long as you get the RCD with the same specification i.e 30mA / 80A 230v. The only problem you might have is that RCD's come in different sizes and you may struggle finding one to fit in your consumer unit.
If you require any more information please don't hesitate to contact me.


Answered 18th Jul 2012

I'm not sure if your consumer unit has an old style RCD in there: Many of the older style of RCD, complying with an earlier version of British Standard are no longer available (eg: BS 4293).

Presently manufactured RCDs for the UK comply with BS EN 61008. These replaced BS 4293 RCDs in 1995.

Electrically, a BS EN 61008 30mA residual current, 80A breaking current RCD will perform functionally the same as the same specification BS 4293 RCD. Physically, they are very different beasts. The new RCD will probably fit on the DIN rail of the consumer unit, but the connector for the line busbar may not line up with the adjacent circuit breakers. I really woudn't recommend bodging it to fit. Also, the older RCDs were 4 standard outlets wide (ie: the width of 4 circuit breakers) whereas the BS EN 61008 ones are only 2 units wide, leaving a gap in the front panel of the consumer unit for some hapless person to poke his/her fingers into.

So - no. Don't replace an old style RCD with a new one. Unfortunately, that means a replacement consumer unit.

You *could* try to get hold of an older style RCD on eBay. I have seen them on there, but - to be on the safe side - you'd need to get the same manufacturer's model to ensure it fits the consumer unit/busbar. These will also be 2nd hand - "rescued" from an old consumer unit that's been replaced. If they say it's refurbished, they will almost certainly not be telling the truth!

If your present RCD *is* BS EN 61008, then there's still every possibility that one from a different manufacturer may not line-up with the circuit breakers' line busbar I'm afraid, though at least it wouldn't leave you with gaps in the front panel!

Again; eBay may be the place to look for a 2nd hand RCD from the same manufacturer.

Hope that helps.


Answered 18th Jul 2012

Yes as long as it is the same fit/same spec.


Answered 18th Jul 2012

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