Consumer Unit Single RCD incomer acceptable?

To my mind it's all down to whether 'service conditions allow' - and the person probably best positioned to tell you that is the user/customer. If they're happy with a single RCD covering everything than that's fine. I would probably offer them the option of positioning the RCCB(s) after the CU for the affected circuits (one for the sockets, one for the cooker?) or even a CU change (for an all RCBO option) and let them pick.

   - Andy.

“Would the Forum like to comment/propose a reasonable, effective, compliant alternative approach?”


Replace the consumer unit?


Andy B.

Well, it's a modest 2 bed  flat , so no outdoor lights or rambling wiring to outbuildings, nor the array of IT equipment you may get with a large family. I reckon the only time the RCD will get near to tripping is if there is a faulty appliance. It may not be to the latest recommendations, but I do not see it as especially  bad.


It may be worth thinking about an emergency light fitting I suppose, depending on the location of windows relative to the street lamps, and communal lighting by the front door,  but there are plenty of houses with a single 30mA RCD as incomer that are quite happily in use, and only pop off very occasionally. The RCD needs to be accessible of course.

Not wanting to replace a thirty year old consumer unit that is no longer fit for purpose when a 5-module consumer unit with a main switch and three RCBOs for less than a hundred quid plus labour will bring it up to current standards is just being tight.


If this is a tenanted flat omitting RCD protection purely on the basis of cost would be absolutely disgraceful, if it is owner occupied doing do is slipshod.


I would never say never to Installing a upfront 30 mA RCD in the tails, but it is the last resort.


And yes, I do mean three RCBOs, the boiler can be moved onto the socket circuit.


This arrangement is okay, but it’s not a job to be taking photos of to promote your work.


Andy B.

I agree in a perfect world it would all become DP RCBOs, it is however a significant extra expense on 'move the cooker switch and add one socket'  it rather depends what was asked for.

Certainly with so few circuits there would be very little merit in the 'standard'  2 RCD solution.

sounds like the job has been done and all is fine. After all it is an improvement, with added benefit of no badge of protection required as no notification required?

Many thanks for the input, I didn't consider replacing the C.U. as it would have added a few hundred quid onto the price of relocating a couple of accessories. Also, I hadn't found a requirement in the Regs to justify the more expensive approach.


However, the Forum seems clear that the addition of RCDs is required and there is a bit of reluctance to accept a common RCD. For the future, I think that I will look into adding a couple of rail mounted RCBOs in a metal enclosure(s). Then give the Client the optional price.


Regards

Last year I asked Rexel  aka Newey and Eyre if they had a Newlec RCD to swap this main switch out, the reply was "Yes we have one in Kings Lynn, the price is £70 plus VAT".


At that price a new 5 mod consumer unit with a nain switch and three RCBOs was far better value, obviously more labour, there comes a point where things aren't worth saving. 


Andy B.

Of course the less than a hundred quid price of the consumer unit assumes that there are not any arc fault or surge protection devices, which are still optional at the moment,  but you are supposed to have a discussion about them and record the outcome. 


Andy B.

Sparkingchip:

Not wanting to replace a thirty year old consumer unit that is no longer fit for purpose when a 5-module consumer unit with a main switch and three RCBOs for less than a hundred quid plus labour will bring it up to current standards is just being tight.

. .. .. . … .

This arrangement is okay, but it’s not a job to be taking photos of to promote your work.


Andy B.

Andy, I agree that hardware cost differences are not large.
As a rough estimate, taking the adopted single RCD solution as the basis for hardware cost;-
The downstream two, single pole, RCBO option would be about £20 dearer.
The new C.U. option would be about £35 dearer.
Although the new C.U. is not significantly dearer from a hardware perspective, it would involve the extensive inspection and testing of the complete installation giving an overall project price increase of about £200.
Quite significant when considering the original scope.
There are a number of Registration Body, ESF documents that caution against “over-zealous” coding and unnecessary changing of C.U.
For similar circumstance in the future, I think I’ll continue to hover between the single RCD and the downstream RCBOs.
Thanks