Hi, please could I ask for help with the following...

We are in Bangkok under the M.E.A.

We have a house with an old consumer unit (square d attached pic no1) that needs replacing.

The meter is a 30/100a, is across the road with a cable run of no more than 15m from meter to main breaker, and uses a thw-a aluminium 50mm sq cable to feed the consumer unit.

We think we have an earth, but cannot actually observe the rod in ground, just the cable going to ground and can follow it to the earthing busbar, its about 10mm sq.

We have what appears to be a m.e.n system with a shortcable running from the earth to neutral.

Im looking at a haco or bticino consumer unit, with a 100a main breaker.

We will have 3 x ac's (9000btu x 2, 15-18,000 btu x1)

3 x hotwater heater ( 2x 4500w 1x 6000w multipoint)

1x washing machine, 1x mid size fridge

3 floors of lights and main sockets

Ive seen many diagrams (see attached no.2) of various consumer units where the main tail neutral goes into the ground bar first, before the main breaker, but in my current old setup (as pictured) both the live and neutral goto the main breaker first, and the m.e.n link is installed.

The first (of many) small issues is the incoming tails just about fit through the wall and into consumer unit with no additional space for movement or to move them freely as I will be needed to renew the CU, not least considering its a 50mm sq cable.

I currently have no rcd protection or rcbo.

I was thinking of 2 choices;

1) just using main breaker >mcbs >and then rcbo's for shower heaters, outside lights.

2) main breaker > rcbo's than split with 1 rcd > mcbs

Does anyone kindly have any ideas or opinions that might help me understand what we need to do, or any corrections to what i have stated or understand to be the case...?

Thank you in advance.

Sorry forgot to add pics

The position of the N-E link for MEN to keep with Thai regs is incoming neutral going via the earth bar to the main breaker.

That said, I would use the same arrangement as is used in your current board when you replace it.

Note that if you have an RCBO main breaker then a N-E link placed after that breaker will cause unpredictable trips in your future life.

I would use RCBO's for "risky" circuits - Water heaters, bathroom outlets, outdoor stuff and leave the rest as MCB only.

Since you have a permanent meter (around 4 Baht per unit) there's no requirment for any further inspections so it's up2u and your sparks.

You really need to test that earth is actually an earth.