Tomorrow the electrician will connect a shophouse. The old wiring has been ripped out and a new 15-45 meter is installed.

We will have two consumer units.

The plan is to connect both consumer units with 16mm wire. Maybe add a third cu for the workshop area as that will have a welder (16A) and other power tools.

The first consumer unit will be used for the first and second floor. The other for the third and fourth floor. Both have 5 breakers and earth leakage protection.

The electrician brought a whole bunch he bought before and they are red (4mm), blue (2mm), yellow (1.5mm), green (4mm), white(1mm) and black(1mm).

Is there a strategy here? I suspect green will be earth, and others will be easily recognized as live wires with different diameters. I am ok with that. What will be used for the neutral? Would the neutral not be at least the same diameter as the live wire. In that case i would need one color to be neutral and in more than one diameter or just pick the largest.

Is there a color code i am unaware of?

The official Thai colour code is the same as the US NEC:-

Black - Live.

White / Grey - Neutral

Green - Earth.

Absolutely reserve Green for earth, as a rule of thumb it should be one size smaller than the circuit it is protecting.

Nothing to stop him using different colours for lives so long as he's consistent but each circuit will need a neutral of the same size as the live conductor, so some shopping for white wire is going to be needed.

The 16mm² will likely all be black, identify the ends of the neutrals either with white tape or white heatshrink (which will be brown when he's shrunk it with a lighter).

If you're having multiple consumer units, it's wise (but not required) that you have a single point of isolation, i.e. one switch / breaker that can isolate the whole property.

Thank you Crossy.

I will shop for more white cable.

With the info from this and the other thread i have enough info to look over his shoulder and see if it is done correctly.

Half way through, everything was wired with grey as live and black as neutral.

Also the switches for the lights where in the grey (live wire).

Amazing......

Oh, yeah, the air conditioner installer, wondered what to do with the green/yellow wire. So he just cut it of.

Also used tape of course, but first had to remove those crimped clamps. It so happens that the water pipe connection and the taped electrical connection were right next to each other. Water up and electric below. Decided to change that.

Official installers of Home Pro and Thai Watsadu, they probably learned it from there grandfather who was a rice farmer, or shudder did they learn that in school?

My future planned house build will need some more time and 24/7 guidance. Decided to when the time comes, i will use young and inexperienced people. At least the change they do what i say will happen. The old and/or experienced people are completely useless. (not the first time to encounter complete knowledge with 'trades' people).

Half way through, everything was wired with grey as live and black as neutral.

Also the switches for the lights where in the grey (live wire).

Switches should be in the live wire though

Indeed. At least they did not switch colors. But who knows maybe in the next half i have to do, i see another variation.

I would have ejected this chap from site by now!

Show him this document if you've not already http://www.crossy.co.uk/Handy%20Files/groundwire.pdf

I changed his job description from electrician to wire puller.

I will do the final connections myself.