Hey Bobnick

I don't think you need worry about overloading the Main Switch, it can happen but not often, your service fuse should be in-line to protect against that sort of overload.

Stick with the board, arrange it so the loads are in ascending order, e.g. start with the biggest current's closest to the main switch, and the same from the RCD side, this is good practice.

I would reccomend that you arrange the MCB's in this order

MAIN SWITCH 100A

Cooker 40A
Immersion 16A
Central Heating 16A
Ground Floor Lights 6A
Kitchen and Utility Lights 6A
First Floor Lights (1) 6A
First Floor Lights (2) 6A


RCD - 100A - 30mA Residual current

Garage 32A
Ground Floor Power 32A
Conservatory Power 32A
Kitchen and Utility Power 32A
First Floor Power 32A
External lights 6A

Now theres a few thing's you need to know, firstly all the breakers should be B-Type and not C-Type.

Only the ground sockets need be on the RCD, all the rest are up to you, as a rule of thumb I put all socket's on an RCD, it will only trip if you have a fault.

If the garage has an RCD of it's own in the consumer unit (CU) in there (Garages usualy have a small CU of there own) then there is no need to put the garage on the RCD side of the board in the house.

If however there is no RCD in the garage then leave as is above.

You need to look at Main Earthing and size of tails, for a 100A supply you need to be looking at using 25mm sq double insulated meter tails.

For the Main earthing to the Gas and Water Pipes and any other services you will need 10mm sq single core copper earth cable, this links from the pipe, e.g. water, back to the Main Earthing Terminal (MET) which should be located near the consumer unit.

Supplementary bonding, this is additional earthing to the main bonding, this is usualy carried out in the bathroom, it links all the pipes to each other and then to an earth teminal such as in the light switch or light fitting, this is not run back to the MET, and is run in 4mm sq earthing cable, all of the bonding should be donw with appropriate earth bonding clamps to BS 951.

A few other things to consider

Have you made sure all the cables are the correct size for there application?

e.g.. 1mm/1.5mm for light circuits, 2.5mm for a 32A Ring circuit or 20A radial and so on?

If theres any other questions you may have please feel free to ask

Earth Block -

Earth Clamp -

Well if your sticking to the On Site guide (brown/blue) you can't go wrong, this is just the simplified domestic version of the regs BS7671

You do tend to get used to 450mm, we had allot in high up in the lounge (around 1000mm) when it was wired in the late 70's as the furniture was right below this, subsequently the rest of the house is about 450mm.

Do you know what type of Earthing system it is, e.g. TN-S, TN-C-S or TT?

Hi again

The only difference between the Blue version and the Brown version is that the brown version is updated to Amendment 2, this contains the new cable colours, where they were previously Red (Live/Phase) Black (Neutral), they are now Brown (Live/Phase) Blue (Neutral) the same as flexible cable colours.

You should really upgrade the earth block (MET) if you can, it's the normal way of running the earthing now.

Quote:


I'm not entirely sure what you mean by this, But if you follow the pictures for the TN-S setup in the On Site Guide your good to go, make sure it is the TN-S earthing your looking at and not the other systems as they have a different earthing system.

Yep

You should only have the supply earth clamped to the sheath, never heard of the water & gas bonded to the sheath next to it  

You have the right idea tho, try and find out if the supply earth cable to the CU is 16mm as it needs to be for 25mm sq tails

You should only need a 4-way, 16mm in and out at either end, and 10mm water and gas on the other two.

Hope it all works out for you

Regards

LS

I'm not keen on visible METs - all you need is a kid with a screwdriver & an inquizative mind and you've dot no earthing!

Thanks guys.  I had great difficulty finding the computer with all the lights out

I noticed that the CU earth bar had terminals marked "BOND", but fig 4a of the OSG showed the MET and earth bar separate so I figured that was the best way to go.  The point about young budding electricians is a good one, though with the CU close to the MET there are probably even more "interesting" things to do with a screwdriver.  An ugly MET I could probably live with.

If I understand this correctly, either a separate MET or use of the CU earthing bar are both OK, I just have to bear in mind the points made by Lectrician and Sparkjonny.

Thanks again.  I'd better get on with fitting that CU!

installed in a lockable cupboard.

Should be fun trying to find the keys to the CU (or even the CU) in the dark or better yet, try and put a key in a keyhole while you are watching one of your children doing the robot (with their finger in a socket outlet). I know that should never happen but how many circuits/homes are adequately protected?

There again your child could be doing the robot attatched to the cu, so it is a no win situation.

I have noticed that you dont seem to be putting in linkable smoke detectors or a heat detector for the kitchen. I have not seen the job so dont know how many levels or floor distances, should be one at least on every floor and heat in kitchen.

Here is a site that might help you with this,

www.tlc-direct.co.uk go to the technical section or look up smoke detectors then go to the technical section.

hope this helps mate but you do need them per building regs.

regards T