Consumer Unit RCBO advice

[Terence Arnold]

Hi

I'm ordering a Hager 10 way split load CU and also want to order some RCBOs. I have an old house(1930s) that was rewired in the 1980s then I moved in and built a double height extension in the 1990s.

The lighting and power in old house are on separate circuits and the lighting and power in the extension are on separate circuits. I'd like to put th lighting and power old house circuits on RCBOs and also a 9.8KW shower.

I know I should be ordering Hager type B RCBOs but I heard they do reduced height ones which would be better but the only ones I can find on Sparksdirect are the type A reduced height. Also they don't do an RCBO that would be OK for the shower circuit(45 amp). Are the type A ones ok or should I just get full height type Bs? Also I assum I will just have to have the shower on an 45A MCB?

My sparks coming next thursday to do the job .

 

[Strima]

Ask your sparks what type to order then.

 

[Midwest]

You can't fit RCBO's in a split load CU. Think you need to discuss this with your sparks. Don't know many that would do the project this way, you buying the materials.

 

[Spoon]

Have you not discussed this with the electrician that is coming to do the job on Thursday?
What has the electrician quoted for?

 

[richy3333]

Yet again blinding! Given as you are probably trying to save money be aware the shorter RCBO’s are more expensive. You also have the wrong C.U.
As has benn said, ask your sparks!

 

[Andy78]

Soooo glad none of my customers are like this.

 

[TJ Anderson]

Terence....Murdoch will be along in a sec with a step by step guide for install........

 

[Flanders]

As above You are ordering the wrong consumer unit if you are fitting some seperate rcbo , if you are getting parts yourself ask the sparks to give you a full list of parts as there will plenty of sundries, no need to get the shorter rcbos there plenty of room in the hager CUs for the longer rcbos

 

[Midwest]

As above You are ordering the wrong consumer unit if you are fitting some seperate rcbo , if you are getting parts yourself ask the sparks to give you a full list of parts as there will plenty of sundries, no need to get the shorter rcbos there plenty of room in the hager CUs for the longer rcbos

Or just get the sparks to get the stuff, unless you insist on saving £50.

 

[Terence Arnold]

Already spoken to Spark, he told me he could do this, would just use one of the RCDs for the remaining circuits and would put the circuits I wanted on RCBOs. THis is the Consumer Unit, it is configurable so why wouldn't it be able to be used?:
VML710CU - Hager 10 Way Metal Consumer Unit Amendment 3 with 8 MCB Breakers FREE, Split Load Config 100A Sw 2x63A 30mA RCCB - https://www.sparksdirect.co.uk/hager-10-way-metal-consumer-unit-amendment-3-with-8-mcb-breakers-free-split-load-config-100a-sw-2x63a-30ma-rccb

Reason I'm asking about RCBOs here is cos I wanted to order today and ccan't get hold of him at the moment.

 

[TJ Anderson]

Go all RCBO or go Dual Split.

 

[Terence Arnold]

I'm not particularly trying to save money, if I was I wouldn't be bothering about RCBOs would I? I just wanted a decent CU putting in and found a good deal on Hager . The spark has quoted £200 for fitting.testing,cert etc I'm providing CU and RCBOs. He was quite happy with this or to provide an MK CU himself but I thought Hager was a bit better quality?

 

[TJ Anderson]

If you are going RCBO then you just need a main switch CU without RCD's

 

[TJ Anderson]

I'm not particularly trying to save money, if I was I wouldn't be bothering about RCBOs would I? I just wanted a decent CU putting in and found a good deal on Hager . The spark has quoted £200 for fitting.testing,cert etc I'm providing CU and RCBOs. He was quite happy with this or to provide an MK CU himself but I thought Hager was a bit better quality?

£200 seems steep for an hours work!!

 

[TJ Anderson]

I'm joking. That's a good deal.

 

[Terence Arnold]

I have 7 circuits and wanted to put 3 of them on RCBOs, 2 of them because they were older circuits and one cos its a shower. I suppose to go all RCBOs would cost another £100ish on top , didn't really think it was needed cos those other 4 circuits are newish and I know were installed and tested properly.

 

[Terence Arnold]

Thanks. Spark said it would be OK to put the 3 circuits on RCBOs and the other 4 MCBs on an RCD. Would this cause problems?

 

[TJ Anderson]

You don't need any RCBO'S. They are nice but won't offer any more safety.

An RCBO is an RCD/MCB combined.
The advantage is for single circuit earth faults it will only trip the affected circuit.

The board you have specified has 2 RCD units which cover MCBS. You still have exactly the same level of circuit protection it is just that if there was an earth fault all the MCB'S covered by that RCD would be affected. Circuits arranged sensibly and a healthy install minimise issues.

 

[Terence Arnold]

Thanks for the reply, I'm grateful. I know I don't need the RCBOs, its just as the older wiring was done in the 80s it might be better if I put those circuits on RCBOs so if there are problems(As I'm moving from a fused CU to MCBs) only the individual circuit would go down. I thought this because I was told RCDs are likely to trip when theres problems that wouldn't affect a CU that has fuses. I'm quite prepared to pay the spark extra to check there are no faults on the older wiring and make sure RCDs won't be tripping.

 

[Andy78]

Thanks for the reply, I'm grateful. I know I don't need the RCBOs, its just as the older wiring was done in the 80s it might be better if I put those circuits on RCBOs so if there are problems(As I'm moving from a fused CU to MCBs) only the individual circuit would go down. I thought this because I was told RCDs are likely to trip when theres problems that wouldn't affect a CU that has fuses. I'm quite prepared to pay the spark extra to check there are no faults on the older wiring and make sure RCDs won't be tripping.

This should be done as a matter of course when installing a consumer unit.

 

[TJ Anderson]

Thanks for the reply, I'm grateful. I know I don't need the RCBOs, its just as the older wiring was done in the 80s it might be better if I put those circuits on RCBOs so if there are problems(As I'm moving from a fused CU to MCBs) only the individual circuit would go down. I thought this because I was told RCDs are likely to trip when theres problems that wouldn't affect a CU that has fuses. I'm quite prepared to pay the spark extra to check there are no faults on the older wiring and make sure RCDs won't be tripping.

His inspection and tests will identify exactly what condition your wiring is in and also ensure it will not have existing faults on your system that would cause an RCD to operate. 30 years for PVC/PVC cable is fine and should still be in excellent condition. It's if it's been installed badly / bodged since that there can be issues. ...

 

[Strima]

We don't install RCBOs due to the age of the installation. Get your electrician to either buy the materials or give you a list of what is needed rather than second guess and try to do it yourself cheaply.

 

[Octopus]

I only fit RCBO boards, more expensive to start with but far better in the long run

 

[TJ Anderson]

I explain benefits/disadvantages of Dual RCD with MCB's vs RCBO'S and give them the choice.

 

[bigspark17]

We don't install RCBOs due to the age of the installation. Get your electrician to either buy the materials or give you a list of what is needed rather than second guess and try to do it yourself cheaply.

Why would you not install rcbos due to the age of installation?? I dont install dual rcd units on cu change only rcbos.. only install dual rcd units on new wiring eg rewire/ new builds.

 

[123]

Why would you not install rcbos due to the age of installation?? I dont install dual rcd units on cu change only rcbos.. only install dual rcd units on new wiring eg rewire/ new builds.

Why Dual RCD on rewire/new builds and RCBO on CU change?
Why not Dual RCD on all or RCBO on all, or offer the paying customer the choice?

Most common cause of faults I've come across is not the wiring, it's appliances, central heating, immersion heater and damp/moisture/water.

 

[bigspark17]

Why Dual RCD on rewire/new builds and RCBO on CU change?
Why not Dual RCD on all or RCBO on all, or offer the paying customer the choice?

Most common cause of faults I've come across is not the wiring, it's appliances, central heating, immersion heater and damp/moisture/water.

As its usually 20+ years old wiring set up on cu changes i find that fitting a dual rcd cu is a really poor option due to wiring issues, borrowed neutrals, accumalative leakage i dont feel that giving a cu that if one circuit developes a fault then it should not take out other circuits which dont have faults, after all this is what the customer with the rewirable fusesis used to i.e individual circuit protection.
I dont particulary enjoy cu changes anyway so i quote rcbo boards only on cu upgrades, i do get undercut by people quoting dual board but i am ok with that.
I will offer a dual board on a rewire/new build as all wiring is new by me & these are jobs i am more interested in winnin so quote dual rcd cu & when it comes to installing cu i will give them option (£150) ish extra for allrcbos but usually they dont bother.

 

[suffolkspark]

With only 7 circuits id defo be going main switch board and rcbos, if money is a problem look at lewden.

 

[Baddegg]

Cef do full rcbo boards (MCG) 8 way around £80 + the dreaded....

 

[Terence Arnold]

Money not a problem to within snsble limits, lol. I see what your saying about why not go full RCBO. I'm quite prepared to spend the extra for a good fully RCBO consumer unit. I've seen MK have a 12 way with 6 RCBOs -are these good quality? My spark said he liked them(from screwfix) . I know the CU and RCBOs could be sourced separetly but would rather purchase the whole kaboodle in one go. Will have a look to see whats available.

 

[Octopus]

I would recommend you discuss this face to face with your spark before spending any money ,......

And I have lost count of the number of fuseboard changes where the expected quantities and ratings of rcbos has changed on the day .... I carry stock and spares so that isn’t an issue ...