Planning Power & Lighting Circuits

[Greenside]

When we built the building we are now living in, the arrangement of power and lighting circuits turned out slightly haphazard as I didn’t specify circuit groups and the electrician took the easy way out in several areas so for example cutting the power to the kitchen also switches off the printer in my office next door. Fortunately, they didn’t go as far as mixing power and lighting on the same circuit.

We have now started work on what is to be our family home (if the pound doesn't vanish completely beneath the waves) and I'm trying to be more organised about instructing the electrical contractor. The overall specification, placement of outlets, lights, fans etc was agreed when we signed the contract but this is an extra level of detail. Here is a draft of the notes I'm giving them and the plans to go with them - I'd be grateful for any thoughts on what I may have missed or be about to do wrong...

Main House - General Notes

1. 3 Phase power supply
2. Load Centre sited in Laundry room adjacent to kitchen and protected by an RCBO
3. Fridge (kitchen) and freezer (storeroom) not via main RCBO so accidental trip won’t spoil food.
4. Bathrooms have a power outlets (shaver type) with built in protection.
5. Bathrooms have UK style pull switches for lights
6. A/Cs x 5 have dedicated circuits
7. Oven has dedicated circuit
8. Multi point water heaters x 4 have dedicated circuits
9. Provision for an EV charging point in the car port – 3 phase terminating in a junction box.

Power Outlets – See Power Circuits.pdf

1. Panasonic Full Colour Wide (metallic grey)
2. Grouped in circuits as shown by coloured areas
3. Exterior outlets divided into two areas – Q: should these have additional protection?
4. One circuit provides power to Bike Shed at rear of main house

Lighting - See Lighting Circuits.pdf

1. Grouped in circuits as shown by coloured areas
2. Lighting in 2 areas + Security PIRs x 4 not via main RCBO – Q: should these have their own RCD or just be wired direct in some way?
3. External lighting on one circuit
4. Bike/Tool Shed – behind car port
5. 2 x double power outlets
6. 2 x fluorescent lights
7. Landscape lighting - Q: Is this best run through the house load centre or would a separate one outside in a junction box make sense given the extra wiring required to go in and then out of the house? We have a small consumer unit with a couple of spare circuits in a box where the power comes in from the road.

Lighting Circuits.pdf

Power Circuits.pdf

Edited March 26, 2013 by Greenside

[Crossy]

You've obviously thought quite hard about this so I have few comments:-

1. I would put two power circuits in the kitchen, with the kettle, toaster, microwave etc. the load soon adds up.
2. I would have more splits on RCDs or RCBOs and lose the front end RCBO.
3. Anything outside or powering outside kit should have 10mA RCBOs for maximum safety.

[Greenside]

Thanks as ever Crossy!

Good idea for the kitchen - I'll definitely make that change.

Not sure I follow about not using a "whole house" RCBO though. Wouldn't it mean having an RCD of some kind for every circuit or maybe there's a way of grouping them I haven't come across. Can you elaborate a little, please?

Exterior sockets: Yes. I think I omitted to put that in the notes - 10mA for all of them.

[David48]

Is there any thought possibly given to a separate circuit just for the fridge (refrigerator) when there is an ELCB (Earth Leakage Circuit Breaker) installed on the power circuits?

This is a general question and not specific to the OP ... but he may wish to consider this as well. ... just reread point #3 in the main house ...

.

Edited March 26, 2013 by David48

[Crossy]

Not sure I follow about not using a "whole house" RCBO though. Wouldn't it mean having an RCD of some kind for every circuit or maybe there's a way of grouping them I haven't come across. Can you elaborate a little, please?

If I was doing it I would do this (not the only way of course).

Small incoming 3-phase DB with an incoming 4-pole MCB and outgoing 3-pole MCB to the EV point. If you have any 3-phase appliances feed them from this DB (but I would avoid if possible). It is in this DB where your MEN link should be (if you have one).

Feed three single-phase boards from the incoming MCB, 1 board per phase. You could use a single pole MCB to feed each the individual boards if you wish which would allow you to isolate each board for maintenance.

Each board can have a combination of RCBOs, MCBs for unprotected circuits (freezer) and an RCD protecting further MCBs for protected circuits. Have a look at the split-service arrangement here http://www.crossy.co.uk/wiring/Consumer.html

Spread outlets and lighting between the boards, if you lose a phase you won't lose all the power / lighting in part of the house.

If you use the same "ABB System proM" DBs as we have (which have DIN rail mounting for MCBs etc.) they are readily adapted to whatever you want to do.

[Greenside]

Thanks for your notes. I think I understand - now it's a matter of being clear that the contractor really understands this arrangement. I'm still pissed that a the last guy failed to comprehend how to wire in an expensive Xpelair delay timer I brought over from England (despite a circuit diagram I got him) and left me with a fan that simply switched on and off with the lights.

Edit: Sorry, I meant to ask you what you class as "leaky circuits"?

Edited March 27, 2013 by Greenside

[Greenside]

Leaky appliances = Washing machines, multi-point water heaters, showers etc as these are likely to trip an RCBO?

[Greenside]

I should have added this question to the OP:

I want to ensure I don't end up with the typical Thai "twisted ends" connections and seem to remember there are a couple of types that have been suggested on here and are hopefully available in Thailand.

Can someone refresh my memory, please.

[Naam]

I should have added this question to the OP:

I want to ensure I don't end up with the typical Thai "twisted ends" connections and seem to remember there are a couple of types that have been suggested on here and are hopefully available in Thailand.

Can someone refresh my memory, please.

[Kwasaki]

I should have added this question to the OP:

I want to ensure I don't end up with the typical Thai "twisted ends" connections and seem to remember there are a couple of types that have been suggested on here and are hopefully available in Thailand.

Can someone refresh my memory, please.

Don't forget to tape these as well the plastic falls apart after a while.

[Crossy]

We used these https://www.wagobox.com/shop/pushwire/

Yes, they are available in Thailand, I'll dig out details of the agent.

[Greenside]

I think I was after the pushwire type of connector. I may be wrong but if I recall the plastic type that Naam suggested aren't rated for permanent installations in the UK at least (although I have no idea why not). A huge step up from a twist and a couple of inches of insulating tape, I grant you.

If you can find me the supplier I'll buy a bunch to give to the contractor to take his mind off the increase in complexity of the Load Centre arrangement you kindly suggested!

[bankruatsteve]

Whatever connector you use, they must be inside enclosure and the wires secured within that enclosure or within a few inches from the outside (to wit the US NEC). Actually, twist and tape is OK for that. No matter what the connector, they cannot be free swinging or possible movement of the wire: fire hazard and breakers, RCD's do not protect.