Implications of replacing Consumer Unit?

The bottom board has an RCD so only talking about top board, so implication is if there is leakage on for example the cooker after changing the RCD may trip, but as is unlikely to be a problem. The main reason to go from fuse to trip is should a fuse rupture looking for a new one, should a trip go it is a simple reset.

As to danger of not having RCD well it seems unlikely there would be any where the circuits are not to sockets, unless you drill the walls a lot, so on balance for some one retired who one assumes is not going to be drilling walls, it could be safer without the RCD, or more to point trips.

I say this as looking at lights, when a bulb blows there is a fuse inside the bulb which should if the gases inside the bulb ionise blow, and with 99% of time blow before the fuse in fuse box/consumer unit, but with a trip they act faster, so instead of fuse built into bulb failing the main trip goes so you loose all lights.

So doing a risk assessment I am not convinced moving to RCD protection is the right thing in your case.

ericmark said:

The bottom board has an RCD so only talking about top board, so implication is if there is leakage on for example the cooker after changing the RCD may trip, but as is unlikely to be a problem. The main reason to go from fuse to trip is should a fuse rupture looking for a new one, should a trip go it is a simple reset.
As to danger of not having RCD well it seems unlikely there would be any where the circuits are not to sockets, unless you drill the walls a lot, so on balance for some one retired who one assumes is not going to be drilling walls, it could be safer without the RCD, or more to point trips.
So doing a risk assessment I am not convinced moving to RCD protection is the right thing in your case.

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I don't completely understand what is on the 'anti-RCD' side of your risk assessment?

If one wants 'compliance with current regulations', one obviously has little choice, since virtually everything is now required to have RCD protection.

Kind Regards, John

ericmark said:

So doing a risk assessment I am not convinced moving to RCD protection is the right thing in your case.

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A risk assessment is not applicable in a domestic installation.

scousespark said:

A risk assessment is not applicable in a domestic installation.

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Good to see you. I hope all is well with you and yours.

Is it not the case that, in any environment, when a judgement/decision has to be made (between possible options, or whatever), it will usually be at least partially made on the basis of a risk assessment (whatever one calls it), even if the assessment is a 'subconscious' one?

As I said, my difficulty with what eric wrote was in understand the basis on which his assessment led to the conclusion he suggested.

Kind Regards, John

Roger465 said:

What sort of cost are we talking about to have somebody replace the 2 complete CU’s? Very roughly?

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£500 - £1000

I am considering my mother, and the problems if we lost power, if socket power lost then auto call to call centre so we knew straight away no power, but any other loss other than sockets and we were not auto informed, so she had to try and get to a phone and in a wheel chair so clearly some danger if she needed to transfer, and she had to phone us, she would likely wait until next carer due, at which point they would phone.

With no RCD there was very little chance of loosing lights without power, and the same applies with only the sockets RCD protected, remember looking at "retired, so on a fairly tight budget" so one assumes not walking around with an electric drill fitting new shelves every day, and the question is "Implications of replacing Consumer Unit?" and one of the implications is more likely to trip when a bulb blows. Also of course is if the bulb blows and does take out a fuse, harder to put power back on than if it trips a MCB/RCBO.

So there is not a hard answer, but swings and roundabouts, and he has asked for implications, so this is what we should be telling him, not BS 7671 says XYZ he has not asked that.

So @flameport has answered the cost £500 - £1000, and for me at 70 yesterday with a reasonable income I would fit a new consumer unit or RCBO's as I want the protection, I am also still active, most of the time, and not been living here long so still drilling walls etc. But I can still remember back in around 1985 when I first swapped my fused for MCB's how each time a bulb blow it would take out the MCB, to the point where since the stairs were centre of house, I fitted an emergency light top of stairs, and also one in garage where fuse box was so I could see to reset MCB.

scousespark said:

A risk assessment is not applicable in a domestic installation.

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I would say a risk assessment is very applicable with a domestic installation, including where the distribution unit is located, mothers house under the stairs, OK for able-bodied, not so good for wheel chair bound, last house in garage, with car in garage it had to be driven out to access the fuse board or RCD, this house under the house in the flat, meaning need to walk down set of steps, but many houses a MCB, RCBO, RCD trip is a very quick fix, and this does need to be taken into consideration.

As does toddlers crawling around.

But we are told we should measure the earth leakage, in use this should be less than 9 mA, this is also part of the risk assessment, if we see whole consumer unit leaking < 1 mA then there is very little risk having whole consumer unit on one RCD, however if > 9 mA then circuits need splitting, this is all part of the risk assessment, and the question is implications so in this case all about risk.

Even with the RCD we assess risk when selecting type, we all know most LED lights today use a capacitor to limit current which will not pass DC, and so no need for type A for lights, but we also look at fridge/freezer, washing machine, electric car and we decide if there is a risk that a type AC will not trip, this is all part of the risk assessment.

I would agree to do an EICR we do not consider who lives in the house, if alzheimer's suffer or toddlers are in potential danger even if no alzheimer's suffer or toddlers in the home you would still award code C2, we are not considering if the occupant is skilled or instructed. We have to write a report considering the house may change occupants. But here we are looking at retired people who are "retired, so on a fairly tight budget" and we should be considering that.

Thanks again for the different views on the situation - I had no idea so many factors had to be taken into account... OK, could anybody gie input on my idea about replacing just the fuse cartridge which supplies the pond pump with an RCD unit please?

Is that feasible/sensible?

If available nothing wrong with fitting RBCO, personally I have all circuits RCBO protected, but you said on tight budget, so I felt to try to push you into a CU change was wrong.

ericmark said:

I am considering my mother, and the problems if we lost power, if socket power lost then auto call to call centre so we knew straight away no power, but any other loss other than sockets and we were not auto informed ... With no RCD there was very little chance of loosing lights without power, and the same applies with only the sockets RCD protected ...

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Fair enough. That's one consideration I hadn't thought about, but it's very specific and would not be applicable to the vast majority of households.

For most households, the only downside of RCDs is they increase the risk of losing lighting (or supplies to freezers etc.) but, as I always say, since that can happen just as easily due to a power cut as due to an RCD tripping, the only proper way to address that is by the installation of emergency lighting. Once that has been done, there are even less potential 'downsides' of having RCDs.

ericmark said:

.... for me at 70 yesterday ...

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(slightly belated) Happy Birthday! I'm slightly ahead of you

ericmark said:

I would say a risk assessment is very applicable with a domestic installation ...

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I would agree, hence my response to scousespark.

I think this is particularly relevant given the fact that 'regulations are not retrospective'. In deciding whether one should advise bringing aspects of an installation 'up to current standards', some degree of 'risk assessment' will (should) be part of the decision as to what to advise.

ericmark said:

But we are told we should measure the earth leakage, in use this should be less than 9 mA ...

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Even if measurements are done (which I imagine is very rarely), they are of limited value - since what matters (for a sockets circuit) is what loads may be plugged in to the circuit, not just which ones happen to be plugged in at the time of a measurement.

Kind Regards, John

Roger465 said:

Is that feasible/sensible?

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Feasible - yes, parts are available. https://www.cef.co.uk/catalogue/products/search?q=Memshield 2

Sensible - no, the RCD pods are ridiculously expensive, and you would be buying parts from an obsolete product range, to fit them into a plastic consumer unit that hasn't been made for a couple of decades.
Far cheaper to sling it away and fit a complete new consumer unit with RCBOs and surge protection.

JohnW2 said:

Good to see you. I hope all is well with you and yours.

Is it not the case that, in any environment, when a judgement/decision has to be made (between possible options, or whatever), it will usually be at least partially made on the basis of a risk assessment (whatever one calls it), even if the assessment is a 'subconscious' one?

As I said, my difficulty with what eric wrote was in understand the basis on which his assessment led to the conclusion he suggested.

Kind Regards, John

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My post is specific to the thread and Eric has raised the option of avoiding RCD after a Risk Assessment. The regs refer to the Risk Assessment to override an RCD for sockets but especially excludes dwellings.The

Edited

I'm assuming you mean RCD rather than DVD! But yes you are quite right. ALL domestic sockets ≤32A must have 30mA RCD protection. It is not possible to use the risk assessment get out for a domestic dwelling.

scousespark said:

My post is specific to the thread and Eric has raised the option of avoiding DVD after an RA. The regs refer to the RA to override an DVD for sockets but especially excludes dwellings.

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I presume that either 'predictive text' or a spell-checker have gone a bit mad there

As you say, in a domestic environment, for a new installation, one could not avoid the need for RCD protection on the basis of a risk assessment. However, given that regulations are 'not retrospective', it is (at least to my mind) a bit different when one is having to decide whether to recommend that an existing installation is 'upgraded' - and I would say that that thought process could reasonably be described as a 'risk assessment'.

As I said before, my problem with what eric wrote was in not fully understanding how/why his 'assessment' came to the conclusion that it did.

Kind Regards, John

I have not said I don't carry out risk assessments in a domestic environment. I just said the Risk Assessment to omit RCD protection does not apply in this posters case.

I would agree that we carry out risk assessments all the time.

@Roger465 if it's any comfort I have a 1950s ex council house that had been rewired in the 80s and had various dubious looking changes over the years. We had an EICR done and the wiring was deemed to be fine. We made a few changes and had a new consumer unit installed and it was about £400 IIRC.