My wife's 2 story family home needs rewiring.

[CapraIbex]

The house is located in a very rural environment.

The existing electric power supply comes from a nearby power pole and runs through one meter unit.

 

"Licensed" village sparkies may not be familiar with my plan viz:

For convenience and manageability, I'd prefer utilizing two (2) SAFE T CUT electrical control cabinet consumer units with front-end RCBO - one (1) for downstairs and one (1) for upstairs.

 

The 'upstairs' electrical control cabinet would receive its electrical power by splitting the incoming power cable just before or at the connection to the main circuit breaker of the 'downstairs' electrical control cabinet.

 

I would install two ground rods, one for each electrical control cabinet.

 

BTW: My wife is happy retaining the existing (one) meter arrangement.

 

Would this general idea be safe and sound for piggybacking two (2) control cabinets to one (1) incoming power supply?

[sometimewoodworker]

42 minutes ago, CapraIbex said:

Would this general idea be safe and sound for piggybacking two (2) control cabinets to one (1) incoming power supply?

No.

 

the ideal is splitting the supply in a separate small box like this

 

you can disregard the surge protector and it’s MCB.

 

Then consumer units for each area. I earth rod or if you want 2 earth rods bonded, so 1 earth connection (you will probably bond the earth an neutral as the supply enters the house)

2 separate earth rods for different parts of the house allows for some very exciting fault conditions, so is an extremely bad idea.

 

However depending on how many circuits you have you can do everything from a single consumer unit with 2 independent zones each with its own RCBO

 

 

[CapraIbex]

Thanks for responding and valuable advise.

I was able to locate a SAFE T CUT electrical control cabinet (separate small box) for splitting the power supply and am proposing fitting it out with a suitable sized Main Switch and two (2) suitable sized breakers one of which would feed the downstairs unit and the other would feed the upstairs unit.

If this sounds feasible and safe what would be the recommended size/capacity of the Main Switch and breakers?

Concerning fastening the electrical equipment to earth.
Naturally, for safety reasons I wish ground the electrical connections properly.

Would you endorse grounding the "separate small box" only and then connect the ground wire to the two (2) SAFE T CUT electrical control cabinet consumer units with front-end RCBO ?

[Robin]

If you want to do this, good luck with getting  local 'electrician' to do what you want.  In my experience, anything they have not seen before will be rejected as "not how Thailand does it"   Earth wire is not often understood, nor is cable current carrying capacity.

Most of all, make sure they keep to a colour code fro all wiring; live should always be th same colour, (brown or red, normally)  and this should be switched, not the neutral return, from lights, appliances, etc.

if you are going to use 'modern' 3 pin sockets, then keep to the same convention for wiring each pin, and make sure they are all earthed..  Best of luck in trying o find twin+earth cable for wiring.

[CapraIbex]

23 minutes ago, Robin said:

Best of luck in trying o find twin+earth cable for wiring.

This is not what I proposed. Rather than your "twin+earth cable" wiring method,  I inquired about extending/connecting the SINGLE ground cable from the "splitter box" to the other two cabinet consumer units. And the whole idea for grounding does indeed encompass earthing all 3-pin plug sockets.

[sometimewoodworker]

2 hours ago, CapraIbex said:

Thanks for responding and valuable advise.

I was able to locate a SAFE T CUT electrical control cabinet (separate small box) for splitting the power supply and am proposing fitting it out with a suitable sized Main Switch and two (2) suitable sized breakers one of which would feed the downstairs unit and the other would feed the upstairs unit.

If this sounds feasible and safe what would be the recommended size/capacity of the Main Switch and breakers?

Concerning fastening the electrical equipment to earth.
Naturally, for safety reasons I wish ground the electrical connections properly.

Would you endorse grounding the "separate small box" only and then connect the ground wire to the two (2) SAFE T CUT electrical control cabinet consumer units with front-end RCBO ?

While you can get a Safe-T-Cut branded box, you don’t have to. We got ABB boxes, they are available in a verity of sizes, our main incoming box is an 8 space but a 6 will be enough. 1 x 2 pole incoming then 2 x 2 pole to feed each sub CU

 

If your PEA supply is TNC-S then you bond the neutral and earth before the first breaker and take the earth feed to each Consumer Unit.

 

PEA wants a whole house RCBO I think that an RCBO in each sub CU is better as a fault will only cut power to 1 section. You can go the whole hog and put individual RCBOs on every individual circuit if you really want.

 

as to the main breaker and sub breakers you can see (in the picture above) what we have with a 30/100 supply, as I don’t know your loads or supply I can’t comment. 
 

under is a drawing by the forum guru for a 15/45 supply including a whole house surge arrestor. It is the diagram for the box pictured above except upgraded for the larger supply.

Edited February 11, 2022 by sometimewoodworker

[sometimewoodworker]

2 hours ago, Robin said:

Best of luck in trying o find twin+earth cable for wiring.

That is almost always a U.K. term and as such isn’t understood, however 3 core cable is widely available. We just popped into our local supply store and picked up 2.5mm VAF-G last week

 

though most commonly wiring is done with single core cable in conduit if it isn’t surface mounted.

Edited February 11, 2022 by sometimewoodworker

[sometimewoodworker]

5 hours ago, sometimewoodworker said:

. 
 

under is a drawing by the forum guru for a 15/45 supply including a whole house surge arrestor. It is the diagram for the box pictured above except upgraded for the larger supply.

I’ve just noticed that it isn’t the same setup as the box pictured as the right hand setup is for a voltage limit switch, and they have been displaced into the sub CUs

[CapraIbex]

20 hours ago, sometimewoodworker said:

While you can get a Safe-T-Cut branded box, you don’t have to. We got ABB boxes, they are available in a verity of sizes, our main incoming box is an 8 space but a 6 will be enough. 1 x 2 pole incoming then 2 x 2 pole to feed each sub CU

 

If your PEA supply is TNC-S then you bond the neutral and earth before the first breaker and take the earth feed to each Consumer Unit.

 

PEA wants a whole house RCBO I think that an RCBO in each sub CU is better as a fault will only cut power to 1 section. You can go the whole hog and put individual RCBOs on every individual circuit if you really want.

 

as to the main breaker and sub breakers you can see (in the picture above) what we have with a 30/100 supply, as I don’t know your loads or supply I can’t comment. 
 

under is a drawing by the forum guru for a 15/45 supply including a whole house surge arrestor. It is the diagram for the box pictured above except upgraded for the larger supply.

Thanks again for your excellent input.

I really don't have any branded preferences concerning the consumer units. As far as I can determine both ABB and SAFE T CUT seem to fit the bill and am going to obtain what's available locally.

 

Quote

PEA wants a whole house RCBO [...]

I intend to comply with PEA's requirements but am almost sure that they won't carry out a inspection after completion of work. I purely rely on the local electrician for completing the installation and most importantly ensuring safe use.

 

Quote

I think that an RCBO in each sub CU is better [...]

This is what I intend to do, i.e. 2 consumer units (CU) with RCBO for each downstairs and upstairs residence. As you had recommended previously, the power to these 2 consumer units will be provided via a separate smaller consumer unit ("splitting box") without residual current circuit breaker (RCBO) and miniature circuit breaker (MCB).

 

With respect to surge arrestor specifically to my intended electrical installation.
Would an arrestor installed to the "splitting" box be adequate or should a surge arrestor be incorporated to each RCBO consumer unit?

 

I leave up to the sparky to work on the load requirements for each individual breaker. He worked on 3-core cable installations before and is familiar with its colour coding.
My main concern is earthing the "3-consumer unit set-up" and hope he will be able to complete this properly.

Is there a gadget available for checking that the grounding connection is done correctly?

[sometimewoodworker]

6 hours ago, CapraIbex said:

As far as I can determine both ABB and SAFE T CUT seem to fit the bill and am going to obtain what's available locally.

HomePro has the ABB units

6 hours ago, CapraIbex said:

I intend to comply with PEA's requirements but am almost sure that they won't carry out a inspection after completion of work.

If they check they will want to see an earth rod and that the main incoming breaker is correctly sized.

 

6 hours ago, CapraIbex said:

I purely rely on the local electrician for completing the installation and most importantly ensuring safe use.

That means that you can probably tell me the next winning lottery ticket numbers ???? there are vanishingly few local electricians, just people who do electrical work. We are extremely lucky that we know a real one.

 

incidentally for anyone in the northeast, he is available on weekends for private work. PM me for more information.

 

you haven’t put your location in your profile, so nobody can recommend an actual electrician who does work in your area.

 

6 hours ago, CapraIbex said:

With respect to surge arrestor specifically to my intended electrical installation.
Would an arrestor installed to the "splitting" box be adequate or should a surge arrestor be incorporated to each RCBO consumer unit?

The GURU AKA @Crossy designed my house plan, it has 1 in the incoming box as you can see.

 

However he has probably more in his house than cockroaches or geckos (no house in Thailand is free from either). Again you don’t say where you live and the chances of surges, usually lighting induced is variable.

6 hours ago, CapraIbex said:

My main concern is earthing the "3-consumer unit set-up" and hope he will be able to complete this properly.

He may, you should check to see if you have a TNC-S supply, you do this by looking at the PEA poles rough every 3rd one will have an earth cable if you do have a TNC-S supply,

 

6 hours ago, CapraIbex said:

Is there a gadget available for checking that the grounding connection is done correctly?

Yes, it’s extremely unlikely that he has one, they are not cheap at all. If he does have one then you have a unicorn, ???? a real electrician.

 

in the house, one of these 

will be a useful check

Edited February 12, 2022 by sometimewoodworker

[Crossy]

In no particular order:-

1. I have one of these, works well and includes a handy RCD tester https://www.lazada.co.th/products/i316566794-s634644285.html 
   I do have a proper earth tester, but they are not a cheap beastie.
2. If you already have a permanent supply (about 4.2 Baht per unit) no inspection is required whatever you do (unless you send your meter into orbit of course).
3. Put a BIG surge arrestor in you main incoming box, smaller ones in the satellite boards can do no harm. As @sometimewoodworkersuggests ours have been breeding! You can never have too much supression.
4. The main box is where your N-E (MEN) link should be implemented IF you are TNC-S.
5. This is also where your earth rod should connect to your earthing system (avoid multiple rods if at all possible).
6. I wouldn't bother with a whole-house RCBO, put one in your satellite boards or have individual RCBOs on "hazardous" circuits.

 

[CapraIbex]

17 hours ago, sometimewoodworker said:

HomePro has the ABB units

If they check they will want to see an earth rod and that the main incoming breaker is correctly sized.

 

That means that you can probably tell me the next winning lottery ticket numbers ???? there are vanishingly few local electricians, just people who do electrical work. We are extremely lucky that we know a real one.

 

incidentally for anyone in the northeast, he is available on weekends for private work. PM me for more information.

 

you haven’t put your location in your profile, so nobody can recommend an actual electrician who does work in your area.

 

The GURU AKA @Crossy designed my house plan, it has 1 in the incoming box as you can see.

 

However he has probably more in his house than cockroaches or geckos (no house in Thailand is free from either). Again you don’t say where you live and the chances of surges, usually lighting induced is variable.

He may, you should check to see if you have a TNC-S supply, you do this by looking at the PEA poles rough every 3rd one will have an earth cable if you do have a TNC-S supply,

 

Yes, it’s extremely unlikely that he has one, they are not cheap at all. If he does have one then you have a unicorn, ???? a real electrician.

 

in the house, one of these 

will be a useful check

Thanks for info and photo shots.
I edited my profile.
My wife's house is located about 12km south of the New Buriram I-Mobile stadium.

[CapraIbex]

16 hours ago, Crossy said:

In no particular order:-

1. I have one of these, works well and includes a handy RCD tester https://www.lazada.co.th/products/i316566794-s634644285.html 
   I do have a proper earth tester, but they are not a cheap beastie.
2. If you already have a permanent supply (about 4.2 Baht per unit) no inspection is required whatever you do (unless you send your meter into orbit of course).
3. Put a BIG surge arrestor in you main incoming box, smaller ones in the satellite boards can do no harm. As @sometimewoodworkersuggests ours have been breeding! You can never have too much supression.
4. The main box is where your N-E (MEN) link should be implemented IF you are TNC-S.
5. This is also where your earth rod should connect to your earthing system (avoid multiple rods if at all possible).
6. I wouldn't bother with a whole-house RCBO, put one in your satellite boards or have individual RCBOs on "hazardous" circuits.

 

Thanks for chip in with additional info/advise.

Re: 2 - The house is already connected to a permanent (PEA) power supply.

Re: 3 - Assuming installing 3 consumer units I'm struggling to determine the sizes of the surge arrestors recommended/required as BIG and/or small seem somewhat subjective.

Re: 4 - I still need to check if the house is connected to TNC-S.

Re: 5 - Understood, install one rod only.

Re: 6 - Each individual level/story will have a 8kw water heater and intend to install a RCBO to the respective consumer unit - hope this is satisfactory.

[Crossy]

21 minutes ago, CapraIbex said:

Assuming installing 3 consumer units I'm struggling to determine the sizes of the surge arrestors recommended/required as BIG and/or small seem somewhat subjective.

 

Sorry about that, we have these 100kA units on our incoming supply, they should take the bite out of anything on the mains :-

 

 

And these smaller 40kA units on the sub-boards which should finish off anything that gets past the big chaps (this one is for our solar, hence the Franke DC devices to the left which are on the DC from our panels).

 

 

Your RCBO plan sounds good.

 

[CapraIbex]

15 minutes ago, Crossy said:

 

Sorry about that, we have these 100kA units on our incoming supply, they should take the bite out of anything on the mains :-

 

 

And these smaller 40kA units on the sub-boards which should finish off anything that gets past the big chaps (this one is for our solar, hence the Franke DC devices to the left which are on the DC from our panels).

 

 

Your RCBO plan sounds good.

 

Many thanks for detailed arrestor info and reassurance concerning my RCBO plan.

[sometimewoodworker]

2 hours ago, CapraIbex said:

Re: 4 - I still need to check if the house is connected to TNC-S.

Re: 5 - Understood, install one rod only.

4) Yes

5) 1 earth connection, but it can be as many rods as you like as long as they are all connected to each other before connecting to your panel 

 

 

 

[sometimewoodworker]

2 hours ago, CapraIbex said:

Re: 2 - The house is already connected to a permanent (PEA) power supply.

There will be no PEA inspection. 
 

unless you manage to start blowing PEA transformers or destroy your meter ???? both of these, though possible, are extremely difficult to do without a truly inspired local idiot / electrician 

Edited February 13, 2022 by sometimewoodworker

[CapraIbex]

23 minutes ago, sometimewoodworker said:

There will be no PEA inspection. 
 

unless you manage to start blowing PEA transformers or destroy your meter ???? both of these, though possible, are extremely difficult to do without a truly inspired local idiot / electrician 

Good video info, thanks.