jim234

Any recommendations for drywall ceiling skimmers/plasterers and interior painters in the bkk area? 

English is not required

Thank you!

Any recommendations for a quality electrician in or around bkk would be highly appreciated. Need complete house wiring, according to architectual plans, of a new build. (possibly more)

English is not required

Thank you!

9 hours ago, Crossy said:

Yeah, just export your earth from CU1 to CU2, just one rod and one N-E bond.

 

I would feed the 10mm² to CU2 with a 50A breaker to give some discrimination but in the event of a short all bets are off as to which MCB will actually open first.

Ok a 50A breaker it will be!

9 hours ago, bluejets said:

It's a mistake to run (as in your case) 4 circuits from each of the rcd's.

Any one of which will trip the rcd and render 4 circuits inoperable.

Single combo's are available here, and I'd argue very little, if any, difference in cost with the added obvious advantage when tripped but also in board space.

I do understand the benefits of using RCBOs and have looked into it. As far as I have found a RCBO set up will cost me about 4x as much though. 

I will have about 30 circuits in total, so I am far from a black out in the event of a faillure where 4 circuits will be cut off. Also, I will divide my light circuits among several RCDs, so there will always be light close by.

So for me it basically comes down to the costs for choosing RCDs instead of RCBOs.

16 minutes ago, sometimewoodworker said:

That is of course if you don’t have an indoor hydroponics weed grow operation so have huge numbers of lights ???????????? 

Haha, I might be Dutch but have no plans in doing so (yet)

The load is been divided quite equally among the 3 phases. I assume the Earth bar from CU2 can be connected to CU1? No extra rod is needed, right?

54 minutes ago, sometimewoodworker said:

The general usage is, no you don’t need that. In general the vast majority of people here treat each phase as single phase after the main incommer. 
So you have a single phase for the ground floor, a different phase for the first floor and the third phase supplies the second floor.

Thank you, that does make more sense!

My plan now is as follows;

-secure 1 phase in the main CU with a 40A MCB

-use a 10mm2 cable (L-N-E) to go upstairs to connect my 2nd CU

My 2nd CU will have;

-40A main switch

-40A,30mA RCDs  (total of 3)

-MCD not exeeding 20A    (total of 12)

Does this seem like a good set up? No ´selectivity´ issues here, right?

4 hours ago, Crossy said:

• Have you considered how to connect all those neutrals to the incoming neutral?
• Similarly, three lives to each of the incoming lives?

because of the size of the CU (3 boxes) I was thinking to go from one RCD to the next, so most RCDs will have 2 N´s and 2 L´s connected on the top of the RCD (is that called parallel?)

I could make a main N-bar and a L-bar for each phase, but because the size of the CU I thought that might get a bit messy

5 hours ago, Crossy said:

You might want a non-RCD protected circuit for your freezer (coming home to a defrosted freezer in a tropical country is not fun). 

that sounds like a good idea!

5 hours ago, Crossy said:

• Do think about adding lightning surge suppression.
• And under/over voltage protection.

I have no experience with both of them, I will look in to that.

5 hours ago, Crossy said:

Are you considering solar?

Yes, I do plan on adding a solar system. Not sure yet on the details. Once I have my CU sorted out I will read the solar forum on here!

5 hours ago, Crossy said:

A backup generator?

We are in Bangkok, so I reckon a generator won´t be necessary.

5 hours ago, Crossy said:

You must have a pretty big place, running sub-mains and having local consumer units for each zone may prove more economical on cable. Same for the shed/man cave.

Actually, that´s what I wanted to do, but reading through some forums discussing ¨selectivity¨ kind of put me off. Again, I´m probably overthinking things.

Please advise me on this;

If I want to place a second CU upstairs (approx. 15m from the main CU)

I assume I need to bring all 3 phases?

What size of cable do I need?

How to secure the 2nd CU in the main CU? With a MCB? Or can I just bring 3L+N straight after the main switch?

Does my 2nd CU need a main switch rated lower than the main switch in the 1rst CU?

Can the RCDs in the 2nd CU have the same rating as the RCDs in the main CU?

How many sub CUs can a system have? When does ´selectivity´ comes in?

It will indeed safe me quite a lot on cables and will make the overall installation easier!

6 minutes ago, OneMoreFarang said:

I found a supplier in Thailand for Type A and Type B.

เบรคเกอร์ MCB กันดูด (RCCB) ABB (pnbmart.com)

Good that they are available at all. But they are very expensive in Thailand.

Thanks for that! Expensive indeed. I still have some lying around here which I plan to use, but it is good to know that they are available there.

2 hours ago, Crossy said:

Do a sketch of what you propose to do and let the brains that know analyse.

I am not very skillful with Paint but I hope the following sketch makes sense

The heaviest loads I have are two 32A´s, they are for ceiling cassette aircons. Two 20A loads are for the garden circuits, the other two for my workshop. Everything else is for inside the house.

I am aware of the MEN link, main neutral bar after main switch, and the appropriate size for wiring.

Am I good to go like this? 

13 minutes ago, Crossy said:

I really think that you are over-thinking here, you will end up with a vastly over-specified system, of course that won't hurt anything other than (maybe) your wallet.

You are probably right on that one!

13 minutes ago, Crossy said:

Do a sketch of what you propose to do and let the brains that know analyse.

Will do, thank you!

7 minutes ago, Crossy said:

In reality your 40A RCDs will be fine, they don't explode or stop working at 40.01A.

 

If worried keep the total of the breakers controlled by said RCD to <40A.

The MCBs behind the RCD will be less than 40A. I calculate that by taking the highest MCB plus 40% of the value of the others. I believe that is the right way to do it, right?

17 minutes ago, Crossy said:

In reality your 40A RCDs will be fine, they don't explode or stop working at 40.01A.

If I do get a 45A supply on each phase, won´t that be an issue with the 40A RCDs? Thought that they won´t be able to handle that.....

or... the amp going through will never extend the amp of the demand? So even if the supply is 45A, that doesn´t necessary mean that 45A will pass the RCD, correct?

15 minutes ago, Crossy said:

Putting an MCB in front of the RCDs seems like overkill although it does let you kill all juice to that section without turning off the whole installation.

ok clear, thank you!

11 minutes ago, Crossy said:

EDIT I must do that drawing I promised, sorry it's been chaos at work.

  No worries, you have been very helpful already!

7 minutes ago, Crossy said:

You will likely get a 15/45 3-phase which is 45A per phase (usual incomer 50A - increase to 63A when the inspector has gone).

Does this mean if I have 50A or 63A main breaker, 40A RCDs are not safe to use? 

Do I need 63A RCDs instead? 

On 9/26/2023 at 9:39 AM, Crossy said:

 

I have noticed that there are 63A MCBs being used in front of the RCDs. 

Although we use 40A RCDs here, we never place a MCB in front of a RCD. Is this done because of the higher Amp?

Thanks so far for all the help! Yet another question;

How much Amp is a typical 3 Phase supply in Thailand? 

Where I a from a standard 3 Phase supply is 3x25A. Therefore the main breaker and all RCDs are rated 40A. (Which also leaves room for a EV system per phase.) 

I still have quite a few new 40A RCDs and a main switch lying around here which I was planning to bring to Thailand. But reading through this forum makes me wonder if a 40A set up is suitable for Thailand. Many on here seem to use 63A (or even higher) as a main breaker. Why is that?

Am I safe to use a 40A set up in Thailand as shown in the diagram here below?

main breaker 40A, 400V

                     -------> RCD 40A, 30mA

                                   ------> MCBs not exceeding 40A (highest circuit + 40% of others)

I´ll be having 9 RCD groups in total

5 minutes ago, Crossy said:

Let me do a sketch once I get home, I don't have Visio on my office machine.

 

If you do it like the inspector is expecting then he will be happy.

 

The inspections usually are pretty minimal, if he sees what he expects to see. Ours was 30 minutes max, 25 minutes of which was him drinking coffee and gassing with Madam. He looked at the rod, and the MEN routing, noted our RCDs and moaned that the poles weren't straight.

Thanks for that, I really appreciate it!

Yes, I agree with doing it like the inspector expects it to be done.

The main reason why I opted for using 2P MCBs is that I could only find C-curve MCBs in Thailand. 1P breakers are not available here in Holland, so I thought to bring 2P breakers instead. Anyways, I now understand that using C-curve is not a big issue, so I will buy my MCBs in Thailand. I probably will bring RCDs Type-A (and 1 Type-B for EV) to Thailand as I can´t seem to find them there.

4 minutes ago, Crossy said:

You need to do something like this with the added N-E MEN routing: -

Thank you! This is all clear now, except for the actual MEN link.

Can I just connect the Neutral CU bus bar link with the Earth bar as a MEN link? 

The PEA diagram shows the N going through the main breaker after the MEN link hence my confussion. So how is N going the the main breaker if it is not actually being switched? 

Thank you all for the replies so far!

Here is a diagram of a typical 3F set up that I´m use to, only the MEN link which I added is new to me.

6 hours ago, Crossy said:

Switching the N on a 3-phase supply is not usually recommended, you need a specific 4-pole breaker which connects N first and disconnects it last. Just use a 3-pole, it's easier and cheaper.

I still have a new 4P main breaker lying around here, thought of using that one. This complies with Dutch regulations.

If I use a 3P breaker, where does the N go? To a N-bar?

The diagram you shared (which is very helpful!) shows the N going through the main breaker too, right? Or what am I misunderstanding here?

6 hours ago, Crossy said:

Making everything 2-pole (or 1P+N) is going to confuse the heck out of the inspector (not to mention your sparking contractor).

Yes this is my main concern indeed.

7 hours ago, motdaeng said:

i wouldn't do that! you can buy quality materials here in thailand, of course, at its price.

the only RCCBs/RCCBOs I seem to find are Type-AC with C-curve. Type-AC is prohibited where I am from (safety issue) and C-curve is hardly being used in a domestic set up. 

I can find some Type-A´s on Lazada but they are all Chinese brands. Not sure if I feel comfortable with them.

8 hours ago, bluejets said:

(1 example) ....Main neutral should not be switched and yes, there should be a neutral link bar as well as an earth link bar.

The MEN link is then, just that, a link between the two.

yes I thought of linking the N bar with E bar, but when I see Thai regulation (also the diagram Crossy shared) I notice that the N goes through the main breaker first before a N bar is created.

6 hours ago, Crossy said:

Personally, I'd stick to the standard Thai kit, single pole MCBs and multiple small ground bars for each RCD.

That might be better then. So bring N through the RCD to create a seperate N-bar.

That means I will end up with 6 (or later more) N bars, no issues with that right? 

To my understanding, PEA will check the following;

Earth Rod

MEN link

Minimal use of 1 RCCB/RCBO (at front end)

After contemplating for a few days and searching on internet, I have decided on the following set up. Please comment if this will work in Thailand. Any suggestions are highly appreciated!

-> MEN link (incoming N goes to E bar before main switch)

-> 40A main switch, 400v (4P)

-> Six RCCBs 40A 30mA type A (2P)

-> Each RCCB feeds 4 MCBs 10A/16A/20A Curve B (1P+N) 

This will give me 24 circuits divided in 6 RCCB protected groups in a plastic (allowed?) DIN rail CU. A 3F set up that I am used to in Europe.

So no N bar is being used! (is this ok for PEA?)

I'm currently in Europe, so I plan to buy all materials here.

Any thoughts on this? Thank you!

2 minutes ago, Crossy said:

The C-curve only affects the magnetic switch-on surge protection, in reality no hazard.

 

The Type-AC RCBO section can be "blinded" by pulsating DC faults, since pretty well everything these days has switching power supplies these days you should really avoid Type-AC (although better than nothing) use Type-A if at all possible.

Thank you!

So no need to worry about C-curves being used, that´s good to know.

I will search further for schneider Type-A RCBOs.

So far only found the Type-AC ones on lazada.

6 minutes ago, OneMoreFarang said:

I have 2 N-bars, separate for each group of MCBs with a RCCB.

And the RCBOs have all separate L and N outputs, no N-Bar. 

And it's important not to mix up the N wires.

So where do the N tails of your RCBOs go to?

How to make it a close circuit?

Back home we don´t use N bars, so that still confuses me a bit

that box looks quite impressive!

5 minutes ago, sometimewoodworker said:

The reason was given above 

7 hours ago, sometimewoodworker said:

It is likely that few Thai electrical fitters know or understand the theory if which category is required and why.

I understand your point.

Just want to know what the safety hazards are by using RCBOs Type-AC with C-curve opposed to using RCBOs Type-A with B-curve. 

Or am I overthinking things by questioning the use of RCBOs type-AC with C-curve? 

20 hours ago, OneMoreFarang said:

Personally I installed two RCCBs with each somewhere between 5 to 10 MCBs - it's not finished yet.

And then I have a few RCBOs for special circuits, i.e. one for the fridge, so that I can easily switch everything off except the fridge. And one RCPO is for my home automation system to make sure that works independently from all the rest.

Does this mean that you have 3 seperate N bars?

One for each RCCB and a third one for your RCBO´s? 

5 hours ago, Crossy said:

Yeah, Type-AC are the lowest of the low, being phased out in several countries Aus being one IIRC @bluejets? Type-AC units can be "blinded" by pulsating DC which is a by-product of switching power supplies.

 

Type-A are recommended as a minimum now. Type-B for your EV.

 

Important Note - we are talking about RCD/RCBO types here https://www.electrical-installation.org/enwiki/Types_of_RCDs#: not MCB tripping curves which are related to start-up surge characteristics.

 

seems like the commonly used RCBO´s here are type AC with C-curve. 

Type AC is prohibited in my home country, curve-C is only used for specific machinery with a high start-up surge. So it does confuse me why they seem to be the standard here.

All RCBO´s that I can find here in Thailand are type C. Are there no type B´s available here?

I thought type B is standard for residential use, type C for (big) machinery use. What is the reason why type C is commonly used here?

When using type C, do I need to cut the max cable lenght into half?

For example: 20A, type B max cable lenght approx. 90 meters

                       20A, type C max cable lenght approx. 45 meters

Any suggestions where to order RCBO´s, cables, etc.? or is lazada the way to go?

thx for that! I´m actually used to wiring 2p breakers, 1p with a Neutral bar is prohibited where I am from. (the Netherlands)

thx for the replies!

My plan was to have 7 RCCB´s with each 4 MCB´s, which will give me 28 circuits. 

Using RCBO´s for each individual circuit does add up. I do understand the advantage of only one circuit being cut off instead of 4, but are there more benefits? It doesn´t make the system more safe than what I am propossing, does it?

 Using RCBO´s for a few special circuits does sound like a good idea.