This (not so good) drawing shows the el supply today:

(EDIT: FIM should be FIL)

The pole has 2 meters - one for cables to FIL house, one for cables to main house. The guest house is fed from a MCB from the CU in FIL house, and will be discarded (cut A).

To feed the guest house should I

1. Split (open isolation and clamp on two more cables) the two blue cables at B for a parallel feed to the two houses, and put in a CU or a single main switch/breaker/RCD in the guest house (one shower unit with ELCB and earthing, unearthed outlets, one earthed outlet, lights). The guest house has an earth rod.

or

2. Take the feed from the the main house. Where? (before/in between/after the main breaker/RCBO/MCB). Use 3 pole cable (for common earth for the two houses) or use the old earth bar in the guest house (the 2 bars in the main house and guest house are separated ca. 10m.)?

If there is a MEN system on the supply side, what implication has this for my best choice?

Thanks.

Is this the same place that has the issues with the heater and the unknown meter size from another post here? It seems you want to do a lot of power supplying with a as yet unknown amount of electrons.

Yes it is - and IMO nothing to be ashamed of.

Thanks to crossy, elkangarito, lopburi3, you and myself I now have a plan for fixing the main house first. It is - as you can see from the other thread - a simple plan: I close the 10 kW heater and install a 3.3 kW wall shower.

I find it prudent - in a boy scout kind of 'being prepared' way - to expect that there will be some painting to do, garden work, repairs, and - most important - cut the 30 or so meters of cable (it's actually 3 times 10 meters knotted, twisted and taped together) from the FIL's house and replace it with something halfway decent. I have even ordered concrete poles to replace the tired bamboo poles supporting the cable to the main house.

I understand that the Thais live here and now - but I like to plan ahead.

Sorry for being a lttle bit pedantic.

philo

PS I also miss my children, so for me it is a good opportunity to go 'home' (it's not my home, it is the home of my wife and children).

Well, I guess I will go for solution 1. That will make the two buildings two separate installations. The only thing shared will be the meter on the pole and the first 40 meters of the blue main supply cables.