Complete Rewire - Advice Needed Please

[Driver]

Hi all,

I'm about to start a complete refurbishment/extension of our house and need some advice. One of the things I've been thinking about is the electrics. I want to make sure it's done right and the setup is adequate for our current needs with some element of future proofing.

Starting with the CU, the contractor is recommending a 20-way split load which will supply 5 bedrooms, 3 bathrooms, a utility room, a large kitchen/diner/lounge, a living room, a play room/home cinema and a server room. There will be LED spots throughout and the server/play room/HC will have have servers/PC/amps (high current) for AV distribution.

In my previous house, when switching on amps or anything high current, we would get a dimming or flicker of the lights. I'm guessing this is because of the old CU and wiring setup but an example of things I want to avoid with the new rewire.

So my questions:

1. Is a split load CU ok or should I spend more on a RCBO? I've read Crabtree is a good brand, any other recommendations? Model's or links would be helpful.

2. We are having dimmable LED spots throughout. In my previous house the dimmer switches would buzz and often bulbs would blow. Again I'm assuming this was down to the old wiring and dimmer switches but want to avoid this with the new rewire. Is there a 'best practice' wiring diagram to show how the lights should be wired? If we have any issues in future, I want the setup to be easy to troubleshoot for any electrician.

Apologies for the long post and thanks for reading!

 

[cprfenom]

Morning.

If you are happy to spend the extra, then I would recommend RCBOs. In terms of brand, then that is often personal preference. Crabtree is a nice brand to use, I know that a fair few of us on these forums use Hager. I would be checking if the contractor will be installing the new amendment 3 board (Hager Design Range) that comes in to full effect in Jan 2016.

Technical Properties VM120K

In terms of your lights, you need to make sure you use dimmable bulbs, and if the circuits are designed right, I would prefer mains voltage. It is well worth spending good money on the bulbs and the LED dimmers.

 

[Driver]

Morning.

If you are happy to spend the extra, then I would recommend RCBOs. In terms of brand, then that is often personal preference. Crabtree is a nice brand to use, I know that a fair few of us on these forums use Hager. I would be checking if the contractor will be installing the new amendment 3 board (Hager Design Range) that comes in to full effect in Jan 2016.

Technical Properties VM120K

In terms of your lights, you need to make sure you use dimmable bulbs, and if the circuits are designed right, I would prefer mains voltage. It is well worth spending good money on the bulbs and the LED dimmers.

Thanks for the reply. With regards to the Hager CU, what is the difference (in laymans term) between a Switch Disconnector and RCCB Incomer? Also why do the Split Load's cost more if they aren't as good as RCBO's?

With the light's do you mean mains voltage rather than using 12v transformers? Any pointers to a diagram that would illustrate a proper circuit to do this?

Thanks again.

 

[SS-2015]

I don't think a split load board will cost more than a board full of RCBO's. Most RCBO's from any of the reputable brands are around the £20 mark - Compare this with £60 for a full RCD split load board.

If cost is no issue I'd go with RCBO's this means if you trip one you will only loose that circuit where as if you you go down the split load board you will loose everything on that side of the board.

Also I agree - I'd stick with mains voltage lights and not transformers, it's less to go wrong which will help any sparky in the future trying to fish around in your ceiling for a faulty transformer.

As far as the lighting circuit itself I'd go with 2 plate design instead of 3 plate (more common) as it can be beneficial having a neutral at the switch.


Also in REF to your high current items, Amps etc...How high current are we talking?

 

[Spoon]

Hi Driver. Are you planning on doing most of the re-wire yourself? I understand why you want to know about different makes and best lights to get but why do you need to know about circuit diagrams.

 

[Driver]

I don't think a split load board will cost more than a board full of RCBO's. Most RCBO's from any of the reputable brands are around the £20 mark - Compare this with £60 for a full RCD split load board.

If cost is no issue I'd go with RCBO's this means if you trip one you will only loose that circuit where as if you you go down the split load board you will loose everything on that side of the board.

Also I agree - I'd stick with mains voltage lights and not transformers, it's less to go wrong which will help any sparky in the future trying to fish around in your ceiling for a faulty transformer.

As far as the lighting circuit itself I'd go with 2 plate design instead of 3 plate (more common) as it can be beneficial having a neutral at the switch.


Also in REF to your high current items, Amps etc...How high current are we talking?

Thanks for the reply. So just to get this right, a Split Load is already populated with circuit breakers(?) whereas with a RCBO you need to buy them separately making them more expensive overall?

With regards to my amps, I have these Model Halo JC 1 « Parasound. Not sure what the actual current is but it peaks at 135a. I also have some servers with dual 1000W PSU's and some PC's. These will be running off the same set of sockets in the server room if that makes sense?

Hi Driver. Are you planning on doing most of the re-wire yourself? I understand why you want to know about different makes and best lights to get but why do you need to know about circuit diagrams.

Hi, I'm not planning on doing any of the work myself, I'm employing professionals. The diagrams etc are just for my info really, I'm quite techie (some say geeky!) so this kind of stuff interests me.

 

[telectrix]

think you'll find that the 135A peak current is at the output side ( extra low voltage) and you should look at the power reqirements ( 1280watts peak) for assessing the load on the installation. this equates to approx. 6A.

 

[Spoon]

Hi, I'm not planning on doing any of the work myself, I'm employing professionals. The diagrams etc are just for my info really, I'm quite techie (some say geeky!) so this kind of stuff interests me.

I totally understand. I'm like that myself. Really interested in how things work. I like to watch the discovery channel as they have a few programs on that go into depth about how things work.

 

[cprfenom]

In regards to your lights, I am not a fan of transformers, but depending on design you may need them.

Hager make a nice switch plate with a neutral terminal integrated on to the back plate.

The biggest advantage of RCBOs is the fact that each circuit is protected separately rather than several by 1 RCCB.

 

[SS-2015]

A Split load board is exactly that - Split into at least 2 banks of Circuit breakers, each bank of MCB's is protected by an RCD device that is usually built into the main switch for that bank.

So with this setup if a fault occurred on any of the Circuits in that bank that caused the RCD to trip it would cut power to that whole bank - Obviously this is a pain as this could cause you to loose some lighting, maybe medical equipment and vital apparatus for pets as just a few examples.

One way around this is to have RCBO'S which is an MCB and RCD combined. With this method if a fault on, lets say the upstairs sockets occurred causing the RCBO to trip it would only take out that RCBO and no other circuits would be affected.

AMP: The Amp almost certainly wouldn't being pulling 135amps if it did you'd have a problem as most domestic supplies are only 100a max.
If you are using high powered equipment and it's permanently sited in a particular room then it may well be worth looking at providing it with it's own supply circuit, like you would with a cooker or Shower.

 

[Spoon]

Can you not buy split load boards where there are some ways that are not part of either bank, that you can then add RCBO's to if you want?

 

[Spoon]

Also Driver, if you have a spare £25 then think about getting this. It will be a good read.
On-Site Guide (BS 7671:2008+A3:2015): Incorporating Amendment No. 3 (Electrical Regulations): Amazon.co.uk: The IET: 9781849198875: Books

 

[SS-2015]

Can you not buy split load boards where there are some ways that are not part of either bank, that you can then add RCBO's to if you want?

Well you can separate the board out however you like - but obviously with doing this you'd still have some circuits protected by a common RCD - I just meant if cost was no issue then RCBO's would be less of a nuisance should a fault occur.

 

[GMES]

Hi Driver I see that you have been a member for 5 years with only 5 posts during that period, Have you got any electrical experience.
The reason for my question is we are more than happy for members to offer up advice and guidance on the latest products available and their preferred install methods but not to hand out an actual wiring diagram to soeone with no experience or qualifications.
Maybe the best thing would be to have a chat with the Electrician you're using for the job and see if he is willing to help you out. but in themeantime feel free to get advice on the other aspects of your question.

 

[Octopus]

This should be in DIY.

You should consider a Hi integrity board or a RCBO board. Do not agree to a dual RCD board.