Hi all,
Am about to start my first rewire next week after qualifying and because of this have done a lot of work into design and cable calcs. I am looking at installing a RCD protected split unit but after some advice on what to put on what side. Some say split between up and down stairs. Some say lights and sockets. Advice please, the circuits are as follows:

Circuit Cable RCD

Shower Back 6mm T&E 40amp
Shower Front 6mm T&E 40amp
U/S Ring Final 2.5mm T&E 32amp
U/S Lights 1.5mm T&E 10amp
Cooker 6mm T&E 40amp
Garage CU 4mm T&E 32amp containing Light Garage 1.5 T&E 10amp Sockets Garage 2.5 T&E 20 amp
Kitchen Radial 4mm T&E 32amp
DS Ring Final 2.5mm T&E 32amp
D/S Light 1.5mm T&E 10amp

Any advice on what needs to go on which RCD protected side would be greatfull. Also any potential problems with the design?

Thanks in advance

Smoke and house alarm?

Anything for the loft - like lighting/sockets/tv distribution?

While I don't know circuit length or details of installation , why not 10mm for shower/cooker - allow expansion/upgrade (even though you don't say what KW the shower/cooker is to be). for the price of cable - seems silly not to.

Bonding going in (Gas / Water)?

How big is the kitchen? Most seem to opt for kitchen/utility as seperate ring as it's often where the high load appliences tend to live (washing machine, drier, dishwasher, etc).

any outdoor lighting/sockets/plugs?

I'm sure there is more I've forgot....just trying to think of what's just gone into mine.

BG

I was going to put 10mm in cooker and showers. But only need 7.5 kw due to awesome water pressures.

All bonding going in also for water and gas intake using 10mm

The kitchen - now this is where i wasnt sure which way to go. I know i have a choice of a 2.5mm ring on a 32 amp or a 4mm radial on a 32. The loading is ok for both. Which way is the safest/most effective/easiest.....

I have left 2 spare ways in the garage cu for outdoor lighting which is going to be a future project once i start on the exterior.

Many thanks for your help BillyGoat.

No worries...just stuff I thought I'd mention.

Ring vs Radial I think is one of those preferences and has been argued to death all over the world. It's up to you at the end of the day. You are creating the design, so it's upto your loading. What sort of distance is it going to be ran?

Mine are all rings - s'what I've always had and it's what works well in my books. Mate said he don't do them at all anymore after having odd behaviour towards the end after high load appliences.

Is this your house to live? Have you considered some Cat5e drops while you are doing it? Have you got an office space and what sort of internettings have you got? I've not done any in the house I'm doign as I'm not living there - but my own has tons. It's flexible enough to be used for phone/broadband and can be a good selling point.

As we move into streaming technologies and faster broadband, wireless don't cut the mustard for high bitrate transfers. Don't care what anyone says, it's something I'm not going to move on with current tech and I have a VERY simple demo.

BG

I'd consider putting in a radial for a dedicated fridge and freezer circuit.
I would also consider using RCBO's instead of RCD/MCCB combination, any fault only takes out one circuit..
How far from the house is the garage or is it attached.

John

_________________
Growing old is compulsory, growing up is not!

Billygoat - the loading is fine and its about 12m run between CU and first socket outlet in kitchen.
This is my house to live. Have tenant in at moment but due to him going away for 2 weeks i have grasped the opportunity to do the rewire in this period before i move in with my family mid year. I haven't thought about Cat5's but will do some research now on them. Are they pretty simple to install?

John. The garage is attached so you are only looking at a 2-3m run if that between CU's.

What order should i install the MCBs and which MCBs do you advise to be on each RCD?

as above.

don't waste your time with 6mm, you will regret it in the end, trust our experience. what makes sense to you now won't in a few years time and you will kick yourself.

for lighting i only use 1.50mm T&E and have done for years, it has more scope than 1.00mm.

as you have only materials to worry about i would use RCBO's on each circuit. that way you need not worry about which circuits are sided with which on the RCD. the usage results are much better for you as well.

radial circuits: -
fridge
freezer
washing machine
tumble dryer

that sort of stops any chance of overload and future proofs your installation.

when wiring in the loft, take all of your cable in between the beams and to each end. don't cross them. this takes more cable but if you ever do a loft conversion, cables are not in the way. i also always wire the ring to the loft for future uses too.

this is very good advice, the way my house was wired its like a sprawling mess of wires over all the joists in my loft horrible and a nightmare as we want a loft conversion.

_________________
- Dave
http://www.pamperhouse.net
http://www.invertedcircle.co.uk

I agree with the main points above.
RCBOs to all circuits, I'd get it done this way if I were replacing my CU.
Loft wiring - take all joist crossings to an end so they are out of the way and not a trip hazard.

As for the cat5e, if you're laying cables, go for it, will make your home network just work. Wireless is ok for surfing on your tablet, but for anything serious, i've only had disapointing experience.

Actually connecting the cat5e is actually quite easy. the sockets just have the same IDC punchdown connections as a phone socket, so if you've done one of them before then you should be fine.
Also if you're laying cables, sattelite wires to anywhere you might want a tv is also a good idea, and freeview too.

Cat5e can also be used for phone extensions, though with cordless and mobile phones nowadays, I don't see the need for this personally.


HTH
J

_________________
I am not a pro.

Many thanks for all of your advice.

I have already bought all MCBs etc. Therefore what order would you suggest:upstairs on one side and down on the other???

Thanks

I'd normally put upstairs lights and downstairs power ring on one side and downstairs lights and upstairs power ring on the other. For the others I'd try and split them based on load, a shower on each side, kitchen on one, cooker on the other, etc

_________________
Cheers,
Darren

Property Refurbishment & Maintenance Dorset

I have argued many times over the use of two RCD's maybe because my house has been wired that way for over 20 years so I have had time to realise the problems.

The point is of course if it's doesn't trip then there is no problem but from time to time cheap RCD's will trip for no apparent reason. One problem is not realising they have tripped and so although there are problems in being plunged into darkness at least one is aware before the freezer defrosts.

My intentions are to swap my RCD's for X-Pole type see this write-up but if starting from scratch I would wire radials in Ali-tube or similar for freezer with no RCD. Mainly for safety as one is often unaware of how long it has been tripped for so all to easy to re-freeze food without realising.

In my case originally wiring on one RCD new wiring on another RCD which includes large lump of kitchen. And the new wiring RCD has in the past tripped without me realising.

EM - do you have shares in that company?

In all seriousness - how often do you actually have tripping problems with RCDs to necessitate the need for such ridiculously overpriced bits of kit?

I've been in my current house for 6 years now and can count the amount of RCD related trips on one hand – all caused by genuine faults, as it was intended to do.

It's functioning perfectly well and has been proven as such with the appropriate test equipment.

I have two fridge freezers, a separate tumble dryer and washing machine – along with a MOUNTAIN of computer equipment. None of this causes erroneous trips.

Given the chance to wire things differently – I wouldn't. In fact, I'm currently renovating a property and have no intention of doing RCBOs or radials to individual appliances.

Perhaps it's time to update – 20 years is quite a while and if you have that much of a problem, you should get someone to investigate and fix the issue if you can't locate it. Not to mention the damage your frequent tripping may have caused over its life.

Just my thoughts....

BG

Em, over the tripping i am with B-goat on that one too as i can also count on 1 hand how many times mine has tripped in the last 20 years but in each case there was a valid reason.
however i don't agree with no doing radials to major appliances. it is very common for people to have 3 major appliances in one area i.e washing machine, dishwasher & tumble dryer, that's a ring overloaded already. a lot of the time it ends up in a kitchen too so you can add a kettle to that as well.

radials to at least 2 major appliances, wiring doesn't get overloaded.

that's just my opinion though but it is the way i have always wired to lower loading.

Interesting point about the freezer on it's own RCD/RCBO I'd not considered that before.

I know there are fridge/freezer alarms which would warn if the temperature rose too high, but is there some kind of plug in alarm which sounds on loss of power?

Or an alarming RCBO which sounds when it trips, this could then be used on a smoke detector circuit etc.

_________________
I am not a pro.