CU. How many 'ways'.

[CallEdsFirst]

1- You can buy stacking kits for some domestic CU's such as MKs. although there is nothing to stop you using commercial boards if you need even more ways. Hager and MEM have interchangeable MCBs between their domestic and commercial boards, although the hager commercial boards are far better looking.

2- Overkill in my opinion, underkill in some areas! Shower cant be on a 100mA RCD to the best of my knowledge. Why separate all the RCD functions? And I cant see any reaon to RCD the lighting rings or even if it is allowed/wise to RCD the smoke circuits!

3- You can either just allow the ways, rough in the cable first fix for the front and rear gardens and leave the ends unterminated and covered (leave pleanty of slack so you can lopp off any that has been affected by moisture if you just hang them outside until they are needed. Alternatively, you could fit MCBs to supply what are effectively sub-mains to front and rear gardens, depending on what is going on in the garden (ie lighting heating sockets etc), run the cables and terminate them in little CUs awaiting the garden circuit additions.

4- Not sure here, again depends on what garden lighting is going in. Might tie in with number three if you choose, there are so many variables here.

Can I just say, what with the various posts in various places and the complexity of what is looking to be a fairly technologically advanced home, you might consider professionals! If you are thinking home automation, a whole new ball game, you might want to consider DIN mounted relays for switching, PLCs for timing etc, a full blown mini BMS to run baths for you when you are on your way home.

Just a thought!

 

[CallEdsFirst]

All that, and you have blatantly hijacked this guys post I have just noticed! Fancy letting me respond to your problem in his post in such a comprehensive fashion!

 

[Adam_151]

Ed,

Its a TT install I think he said, which means that unless very exceptional circumstances exist you need to have some kind of RCD on everything

EDIT: is it? or is simon trying to confuse me

 

[CallEdsFirst]

doesnt a main RCD incomer suffice for that aspect? Anything that feeds off of that is RCD protected even if it is on a mainswitch. The others are just for downstream discrimination?

 

[Adam_151]

doesnt a main RCD incomer suffice for that aspect? Anything that feeds off of that is RCD protected even if it is on a mainswitch. The others are just for downstream discrimination?

Yes, and no, from an EEBADs POV it works, it is however inconvient when everything goes off together (and with lots of stuff on it, the culmative earth leakage means its more likely to nuisence trip!), I know for a fact that the NICEIC consider this (Single 30ma for whole install) in breach of a reg that calls for inconvience to be kept to a minimum in the case of a fault, however not everyone agrees 100% with how the NICEIC interpret things!

 

[CallEdsFirst]

Firstly peeky has a TT supply potentially, Eyeofthebeholder has hijacked the thread but not mentioned what sort of supply.

Secondly, I bow down to your superiour knowledge. But if EOTB's supply is TT, then still just 2 RCDs will suffice surely!

 

[eyeofthebeholder]

1- You can buy stacking kits for some domestic CU's such as MKs. although there is nothing to stop you using commercial boards if you need even more ways. Hager and MEM have interchangeable MCBs between their domestic and commercial boards, although the hager commercial boards are far better looking.

I think I might go for a commercial board if the MCBs are interchangeable - more hardcore and will give be ample spare space

2- Overkill in my opinion, underkill in some areas! Shower cant be on a 100mA RCD to the best of my knowledge. Why separate all the RCD functions? And I cant see any reaon to RCD the lighting rings or even if it is allowed/wise to RCD the smoke circuits!

Sorry, my mistake on the shower. I heard from somewhere with the lighting circuit it is safer to split it off so if there is a failure somewhere else it won't trip all the lights out. You think the smoke CCT should connect direct to the main switch?

3- ..... Alternatively, you could fit MCBs to supply what are effectively sub-mains to front and rear gardens, depending on what is going on in the garden (ie lighting heating sockets etc), run the cables and terminate them in little CUs awaiting the garden circuit additions.

All I have in the rear garden is a single socket and a light on decking at the rear of the garden. The front garden will eventually have a lamppost only (unless I can think of anything else in the meantime ). If I do go with little CUs, which is my prefered option, how do they connect in the main CU? Do they go straght into the main switch or via a MCB or RCD?

4- Not sure here, again depends on what garden lighting is going in. Might tie in with number three if you choose, there are so many variables here.

It will litteraly by just one security light at the front and back - nothing more special than that

Can I just say, what with the various posts in various places and the complexity of what is looking to be a fairly technologically advanced home, you might consider professionals! If you are thinking home automation, a whole new ball game, you might want to consider DIN mounted relays for switching, PLCs for timing etc, a full blown mini BMS to run baths for you when you are on your way home.

This is a project that I want to do myself, with the help of my Dad who is in the building trade (so he can advise me on the non-electrical parts of the overall job). I do realise that somethings are slightly out of my depth, but I think with time and the right attitude towards electicity I think I will be OK. I'm not the type of person who thinks 'Oh, that'll be OK'. I would rather do it correct and therefore not be killed or blow up some expensive equipment!

Getting in the Pro's is an option I have already covered and recieved quotes for the work, but I didn't fell confident in their abilities to do the other non-electrical wiring correctly etc. Also as I don't actually fully know what I want on that side yet (eg networking, AV, intruder alarm, CCTV, and smoke alarms) it's a commitment I don't want to make. I would rather do it in a slower time myself and investigate it as I go along.

I have also thought about home automation, but I think its a tad OTT for the house I am in. I don't really want to turn into a fat American who can do everything in the home from the armchair .

All that, and you have blatantly hijacked this guys post I have just noticed! Fancy letting me respond to your problem in his post in such a comprehensive fashion!

Sorry - I should have really started a new one

 

[Adam_151]

Firstly peeky has a TT supply potentially, Eyeofthebeholder has hijacked the thread but not mentioned what sort of supply.

Yeah, sorry, think I've confused myself it happens occasionly when I skim read the threads

Secondly, I bow down to your superiour knowledge.

Have I said something to offend?!

But if EOTB's supply is TT, then still just 2 RCDs will suffice surely!

Normal practice is 100ma S type incommer and 30ma in a split board config, indeed simplier than what was proposed in the image, but if the OP wanted to split down his installation further then there is nothing wrong with that as long as he mantains the correct protection to all of it

 

[CallEdsFirst]

No offence!!!!

and my argument wasnt that all the RCDs were wrong, just expensive!