Questions about consumer units / fuse boxes

JRT404

Hello everyone. I am looking to replace my fuse box and had some questions which I hope you can help me with. If you have answer to only a select few then that's also fine - still interested to hear your opinions on the parts you know about:



1) What's a better brand, wylex or mk?!

2) How much does a "quality" unit cost? Is it around the £100 mark (for domestic / homes)

2) What is a reasonable price to pay a Part P NICEIC registered electrician for both the unit and its installation in London? Is 300 too cheap?

3) What does "dual rcd mean" as opposed to single rcd

4) What's the difference between rcd and mcb?

5) What does it mean to be compliant with bs7671

6) what does xxx way (e.g. 16 way) mean? Is that 16 switches?

7) Is there anything else salient when buying a unit that I should be aware of?

angel_of_dartford

as long as the board is to BS7671 then I wouldn't worry too much, I've always found MK to be better quality though.

Around £100 is a reasonable price to pay for the unit c/w breakers, check the screwfix website

£300 is a reasonable price for supply and fit, as long as it includes certification

dual rcd means the board is split into 2 sections, so if one rcd trips, the other one doesn't so you don't lose everything in one go

rcd - residual current device - detects an imbalance in the current flowing in live and neutral, and trips if there is an imbalance (e.g. leak to earth)
mcb - miniature circuit breaker - trips if the current flows is greater than the rating (think like a fuse)

rcd is the safer

bs7671 is the british standard for wiring installation (IEE 17th edition)

the number of ways is indeed the number of circuits

would be much less trouble to go down the supply and fit route

Risteard

angel_of_dartford wrote: »

rcd is the safer

Not for anything other than an earth fault.

Cornucopia

16-way = 16 MCBs for 16 circuits. You can match the number of MCBs to the existing Consumer Unit, to ensure it's big enough (though 16 should be more than enough for an average 1-3 bed property).

kaya

i paid £100 for mine from screwfix then £300 to have it fitted a few months back, all signed of and certified

jc808

be aware that non-split load boards dont comply with regs UNLESS you put RCBOs on each way - very expensive

dont buy a board as you dont know what you want

get the sparks to supply

JRT404

angel_of_dartford wrote: »

as long as the board is to BS7671 then I wouldn't worry too much, I've always found MK to be better quality though.

Around £100 is a reasonable price to pay for the unit c/w breakers, check the screwfix website

£300 is a reasonable price for supply and fit, as long as it includes certification

dual rcd means the board is split into 2 sections, so if one rcd trips, the other one doesn't so you don't lose everything in one go

rcd - residual current device - detects an imbalance in the current flowing in live and neutral, and trips if there is an imbalance (e.g. leak to earth)
mcb - miniature circuit breaker - trips if the current flows is greater than the rating (think like a fuse)

rcd is the safer

bs7671 is the british standard for wiring installation (IEE 17th edition)

the number of ways is indeed the number of circuits

would be much less trouble to go down the supply and fit route

Thanks - very useful information.
In terms of rcd vs mcb then. Should I think of mcb as each individual switch on the board while rcd is the big switch that turns a set of switches off?

When you say "as long as it includes certification" do you mean getting an EICR certification? I.e. Should I be expecting them to also include the periodic report (electrical installation certificate) also as part of changing the fuse box?

JRT404

jc808 wrote: »

be aware that non-split load boards dont comply with regs UNLESS you put RCBOs on each way - very expensive

dont buy a board as you dont know what you want

get the sparks to supply

What is a non split load board? Do you mean single rcd?

What is an RCBO aswell please?

JRT404

kaya wrote: »

i paid £100 for mine from screwfix then £300 to have it fitted a few months back, all signed of and certified

Was the certificate an EICR or just a certificate saying it had been installed ?

JRT404

Any more opinions on wylex vs mk please ?

Ectophile

You should get an EIC (electrical installation certificate) when something new is installed. An EICR is a report on an existing installation.

A quick guide to the jargon:

MCB = Miniature Circuit Breaker. Acts like a fuse to prevent overloads and fires, but unlike a fuse you can turn it on again.

RCD = Residual Current Device. They used to call them "Earth Leakage Circuit Breaker", but someone decided to change the name to something that nobody would understand. Stops you being electrocuted if you accidentally touch something live, by shutting off the power very quickly.

RCBO = Residual Current Breaker With Overload. Another over-complicated name for something that's just an RCD and an MCB in the same module.

Modern consumer units should either have two (or more) RCDs, each protecting some of the circuits*, or lots of RCBOs. Or even a mixture of the two - provided that every circuit goes through an RCD or RCBO.

If you have an electrician in mind, you may want to ask them what they would prefer to install. Electricians hate it when customers hand them cheap and shoddy kit to install. They may even be able to get a trade discount if they buy it themselves.

*That's what a "split load" board is. If all the circuits are on one RCD, then one fault blacks out the whole house and you're left stumbling around in the dark trying to find what tripped it.