New Kitchen, new Consumer unit?

[gemius]

Hi
I'm having a new Kitchen fitted in a few weeks with all new appliances. My current unit is as photo.
Am I right in saying that if a new connection or any work needs to be done I must have a new unit fitted with an RCD, but if everything can be run off the existing fuses there's no need to change anything?
You may advise a new unit anyway but as the electrician won't come until the old kitchen has been stripped out I don't want to be bounced into making a decision with everyone waiting to get on with the job.

 

[flameport]

If you don't make any alterations to any circuits, and don't have any new circuits installed, and keep everything exactly as it is now, then in theory you can keep that 30+ year old obsolete consumer unit for as long as you like.

More realistically it's a couple of decades overdue for replacement, new kitchen or not.

a new unit fitted with an RCD,

RCBOs, one for each circuit.
The era of a single RCD is long gone. So is where 2x RCDs were installed.

 

[plugwash]

BS7671 does not give a whole lot of guidance on to what extent existing installations must be upgraded when carrying out alteration works. However afaik most electricians start from the principle that new work should be to current regs. Some electricians are likely to be stricter about this than others.

The problem is the regs don't say consumer units must have RCDs, they say that sockets rated at 32A or less, domestic lighting circuits and most concealed cables must be RCD protected. That means if there is no RCD protection in the consumer unit then it's NOT the consumer unit per-se that is non-compliant but the stuff fed from it. In other words if the electrician doesn't take steps to add RCD protection then any additions or alterations made will not comply with current regs.

I'm pretty sure that CU is from an obsolete range that is not compatible with current products. So modifying it without replacing it (or at least replacing everything inside it, but at that point you may as well replace the whole CU) is problematic.

There are certainly ways that RCD protection could be added without replacing the CU

* A RCD in a seperate enclosure could be added "upfront" in the feed to the CU, the problem with doing this is that it leaves the whole house on one RCD, which is not ideal from a nuisance tripping point of view.
* RCDs in seperate enclosures could be added in a "downstream" on the circuits that will be modified. This would work, but it gets messy the more circuits are involved.
* A second smaller CU could be installed and the relevant circuits moved to it (but nearly half your circuits are feeding stuff in the kitchen, do you want to do half a job?)

But ultimately replacing the CU is generally the sensible option.

Given that it's going to be replaced, there is then the question of "with what"? several descisions to make.

1. Dual RCD vs RCBOs, dual RCD is cheaper but makes nuisance tripping more likely and the source of it harder to track down.
2. Do you want to go with a cheap brand or a well-known one. Well-known brands are likely to support their products for longer but there are still no guarantees.
3. Do you anticipate future expansions, if so you want to ensure the CU has the capacity to support them, and it may make sense to get actual breakers fitted rather than just blanks (see above comment about manufacuturer support of lack thereof down the line).

I would advise getting the electrcian involved before having the kitchen ripped out.

 

[gemius]

OK thanks. I'm convinced. He can do the lot.

 

[JohnW2]

BS7671 does give a whole lot of guidance on to what extent existing installations must be upgraded when carrying out alteration works. ...

Is there a "not" missing from that sentence? If not, could you perhaps expand/explain a bit? Thanks.

Kind Regards, John

 

[plugwash]

yes there was a not missing, edited now.

 

[JohnW2]

yes there was a not missing, edited now.

I'm glad to hear that - otherwise I would hasve been rather confused. Thanks!

Kind Regards, John

 

[ericmark]

@plugwash has given a very good reply, when mothers kitchen was altered when she became disabled there was a problem with the house electrics, the house needed rewiring, but dad put his foot down and said I am not living in a building site, you can rewire it when I'm gone, so needed to find a way around the problem.

The method used was a steel wire armoured cable fed from a large MCB in the original consumer unit and a second consumer unit in the kitchen which just powered the kitchen.

There is always a way to do it, but not always what we really want, in mothers case there was no option but to fit a new kitchen as work services too high for wheel chair use, but had she not lost her leg, then the rewire would have come first.

The problem is until some one has used meters and tested the installation we have no idea if you can simply fit RCD's or RCBO's. We have two main meters, the clamp-on ammeter with a 0.001 amp scale so we can test actual leakage, and the insulation tester which uses 500 volt DC to calculate the leakage, until tested you may have unknown faults, this house in the hall some one had selected the wrong neutral in a 4 gang switch, and upper and lower floor lighting would not work until corrected, lucky just one wire to move.

Many houses need the stairs lighting rewired or wireless switches fitted where lines were borrowed when first installed, referred to as borrowed neutral.

When mothers wet room was being installed (around 2004) I got a phone call from the electrician, he was to fit a second consumer unit with a RCD just for wet room, and for an extra £100 he would fit a new consumer unit for whole house and then whole house would be RCD protected. (This was before the kitchen)

I got to mothers house to find the electrician pulling out his hair, and could not get the RCD to hold in, he as a temporary measure fitted an isolator instead promising to return next day, never saw him again. At least back then not forced with regulations to fit RCD's so technically broke no rules.

Daughter also had problems when fitting RCD protection, it took me all day to find the screw in a socket which had earthed the neutral, so easy to fix, but so hard to find.

OK daughters the electrician had identified the fault before starting, and made an agreement with me I would come next day and fault find. But an electrician should do a part EICR before starting so he knows what the problems are.