Considering CU update

[dormermike]

Hi all

I've two consumer units, crabtrees circa 1990s with MCBOs, one CU for lights and the second for sockets. The only RCDs (RCBO?) are one for garage, and the other for a shower. Am looking at having an induction hob fitted, so adding extra 6mm cable/circuit, so electrician is involved already.

Total mcbo/rcbo in use is 19, but a new one will need to be added, with a separate CU for RCD for the new circuit according to the electrician.

I'm thinking of biting the bullet and getting them upgraded.

Been quoted £1.3k by the electrician, whom I've used before.

It's a lot of money but in theory would make the installation safer is that right? Any other benefits?

What should I be looking for in terms of questions. The quote doesn't include what manufacturer for example and I'd want a quality brand. Any advice appreciated.

Thanks

 

[EFLImpudence]

Your description is very confusing.

Perhaps pictures of what you have would be better - just copy and paste them.

 

[dormermike]

Ok here is a pic. Am getting electric work done for new kitchen incl induction hob circuit (6mm maybe 10mm CSA) and am considering upgrading this lot to have RCD protection on all circuits and current regs, which will also tidy it up. Worth it?

 

[EFLImpudence]

Am getting electric work done for new kitchen incl induction hob circuit (6mm maybe 10mm CSA)

The left hand CU appears to be all RCD protected - albeit by only two RCDs so not ideal by today's standards.

You already have a cooker circuit; this might be adequate for the new hob.

Depending on installation method, 4mm² could be adequate for 32A 'cooker' circuit but everyone still uses 6mm² for historical reasons.

That it is an induction hob makes no difference.

and am considering upgrading this lot to have RCD protection on all circuits and current regs, which will also tidy it up. Worth it?

Well, that is up to you.

You might require RCD protection for new work (as with the shower) so maybe the best option.

 

[dormermike]

Existing cooker circuit will still be used for the cooker, but we're switching out gas to induction, so new circuit required. As its an 8kw induction hob, I believe 6mm is required and electrician seemed to agree, and due to the length of the run said 10mm may be required. I don't see it myself, but who am i to argue..

The RCD's are for single circuits - on the left board one is for the shower and one is for the detached garage. The bottom (separate CU's) RCDs are for additional works that were done a few years ago - underfloor electric heating, and upstairs sockets.

New CU's would consolidate all that, do an electrical installation safety test, and add RCDs to each circuit (some may be consolidated due to borrowed neutrals etc which I know are in place, as well as shoddy NICEIC contractors - see top right box which is just a live connection, neutral is disconnected).

 

[EFLImpudence]

Existing cooker circuit will still be used for the cooker, but we're switching out gas to induction, so new circuit required. As its an 8kw induction hob, I believe 6mm is required and electrician seemed to agree,

A 32A 4mm² circuit (with no derating factors such as running through thermal installation) is adequate for up to 20kW of cooking appliances.

and due to the length of the run said 10mm may be required. I don't see it myself, but who am i to argue..

Can't tell from here.

The RCD's are for single circuits - on the left board one is for the shower and one is for the detached garage. The bottom (separate CU's) RCDs are for additional works that were done a few years ago - underfloor electric heating, and upstairs sockets.

Ah yes, my mistake.

New CU's would consolidate all that, do an electrical installation safety test, and add RCDs to each circuit (some may be consolidated due to borrowed neutrals etc which I know are in place, as well as shoddy NICEIC contractors - see top right box which is just a live connection, neutral is disconnected).

As I said; up to you.

 

[ericmark]

I looked at this house when I moved in, two distribution units, a fuse box and a split consumer unit, but when pricing up, cheaper to renew all with a fuse box consumer unit, to doing any part upgrade. So new 14 way consumer unit fitted, with SDP and all RCBO's. The parts cost from memory £350, and it took the electrician around 6 hours. Done as a favour, no money changed hands, at least not linked to work done, but did pay for his new boiler, so could say it was expensive.

It does seem a lot of money, but not worth doing half a job.

 

[Murdochcat]

£1300 sounds a bit steep - is he VAT registered and does that include VAT?

Fingers crossed the quote is for all RCBO's and SPD , test, inspect, certificate and Part P

 

[EFLImpudence]

What do you mean by 'Part P'?

 

[Murdochcat]

What do you mean by 'Part P'?

Yawn

 

[dormermike]

£1300 sounds a bit steep - is he VAT registered and does that include VAT?

Fingers crossed the quote is for all RCBO's and SPD , test, inspect, certificate and Part P

Yeah i was wondering about the price. That doesn't include £3k for the kitchen wiring, which tbh, is a lot more than i was expecting for 12 downlights, 7 sockets, and a new circuit for a hob.

 

[Murdochcat]

Yeah i was wondering about the price. That doesn't include £3k for the kitchen wiring, which tbh, is a lot more than i was expecting for 12 downlights, 7 sockets, and a new circuit for a hob.

£3k for 19 points and a hob circuit

I’d be getting another price

 

[flameport]

As its an 8kw induction hob, I believe 6mm is required and electrician seemed to agree, and due to the length of the run said 10mm may be required.

Most hobs are around 8kW, induction or otherwise.
Unless the 'run' is over 50 metres long, 6mm will be plenty.
As already stated, a 32A circuit is suitable for 99% or more of domestic cooking installations, whether that's an all in one cooker, separate hob and oven, hob and two ovens, hob, oven, combi microwave and various other possibilities.
You can of course have a separate circuit for each cooking item if you want, but it's certainly not necessary.

considering upgrading this lot to have RCD protection on all circuits and current regs,

All new circuits and additions to circuits will require RCD protection, which you only have in the left consumer unit, and that particular type of RCD is no longer permitted for the vast majority of circuits.
Those consumer units were a quality choice in their day, but that was several decades ago.

Been quoted £1.3k by the electrician, whom I've used before.

Whether that is appropriate depends on what you are getting for that price.
Should be a full inspection and test of all existing circuits, any minor repairs where required, upgrades to main equipotential bonding if needed, a new consumer unit from an established high quality manufacturer with main switch, surge protection and as many RCBOs as required, preferably those with a switched neutral. Several spare ways as well to allow for any future items.
Minimum of an entire days work, and given the number of circuits it could easily take longer.

There ae plenty of other cheaper and substandard options.

That doesn't include £3k for the kitchen wiring, which tbh, is a lot more than i was expecting for 12 downlights, 7 sockets, and a new circuit for a hob.

Unless there are some exceptionally unusual, difficult and complex things in there, that is excessive.

 

[dormermike]

Most hobs are around 8kW, induction or otherwise.
Unless the 'run' is over 50 metres long, 6mm will be plenty.
As already stated, a 32A circuit is suitable for 99% or more of domestic cooking installations, whether that's an all in one cooker, separate hob and oven, hob and two ovens, hob, oven, combi microwave and various other possibilities.
You can of course have a separate circuit for each cooking item if you want, but it's certainly not necessary.


All new circuits and additions to circuits will require RCD protection, which you only have in the left consumer unit, and that particular type of RCD is no longer permitted for the vast majority of circuits.
Those consumer units were a quality choice in their day, but that was several decades ago.


Whether that is appropriate depends on what you are getting for that price.
Should be a full inspection and test of all existing circuits, any minor repairs where required, upgrades to main equipotential bonding if needed, a new consumer unit from an established high quality manufacturer with main switch, surge protection and as many RCBOs as required, preferably those with a switched neutral. Several spare ways as well to allow for any future items.
Minimum of an entire days work, and given the number of circuits it could easily take longer.

There ae plenty of other cheaper and substandard options.


Unless there are some exceptionally unusual, difficult and complex things in there, that is excessive.

Flameport - thank you for this, great info. I've contacted another couple of local electricians to see if they are interested in quoting.

I've a 32amp circuit already in the kitchen i believe, for the existing electric double oven, sounds like that can be re-used for the new induction and new double oven with integrated microwave. Not sure why my electrician proposed a new circuit. Be interesting to see how other quotes differ.

 

[dormermike]

Had another electrician in and he is saying I need to do an eicr test, and then he will quote for a CU including remedial works. This seems reasonable to me, as he can't know what work needs doing without testing, or am I sleep walking into a rabbit hole?

Also for the kitchen he is planning to use the existing cooker circuit/cable for the induction, and put the new cooker (double plus microwave) on a FCU on the ring itself. Seemed like a good solution.

Only thing I'm not entirely sure about is he is saying for downlights it's ok to run the cables under the joist, i.e. not through the joist. Not sure I'm happy about that... Any thoughts ?