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Electrics for new house - can it be explained in layman's terms?


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Posted

The girlfriend and I are in the process of having a new house build, and one of the issues that we have to deal with is the electric installations. I have been reading the different topics in this forum about electrics, but the more I read the more confused I get (it probably doesn't help that I am not a native English speaker). Is there any way to explain what I need for the house in simple terms, that I (and more importantly my "electrician") can understand?

The house will be a fairly standard two storey 3 bedrooms 2 bathrooms house and, of course, the electrical system will be grounded (that much I do understand). Our usage is not that heavy, and I'm sure that a 15/45 Amp meter will be sufficient for us. We will have:

  • Fairly standard amount of lights with fluorescent or low energy bulbs
  • Water pump (200-250W probably) to supply decent water pressure
  • Water heaters in each of the two bathrooms (around 5,000W in each bathroom)
  • Two washing machines (one top and one front loader). Both will be probably be connected to the same outlet, but it's unlikely that both will be used at the same time.
  • Refrigerator
  • TV (currently one, maybe two later on) and satellite box
  • No air conditioners in the beginning, but conceivably two later on (one in each of two bedrooms). If and when the air conditioners will be installed they will be 9,000-12,000 BTU as bedrooms are 16 sq.m. and quite well insulated with 20 cm AAC blocks on external walls and we prefer a temperature around 27 degrees. I will have cabling installed now so it's ready for if/when we install the air conditioners.
  • We will be cooking with gas but the kitchen will have the normal range of water heater, rice cookers, electric wok and maybe one day a small counter top electric oven
  • Laptop computers, printer and wireless router
  • Fans
  • Assorted small stuff

Now that I have given you an idea of our usage requirements, I would like to ask a number of questions that I hope the collective wisdom on this forum will be able to answer - hopefully in a way that even I will be able to understand (or at least can relay to our sparky).

First question:

I want to have some kind of earth leakage circuit breaker that trips if something is wrong and saves our electrical equipment, but I have heard so many different terms used that I don't know what to ask for (ELCB/RCBO/RCD/Safety-cut etc.). Since we are under budget restrains I think one breaker for the whole house will be enough (but what do I know).

What (one) term should I use when I talk with our Thai electrician so that he will understand what I am asking for?

Second question:

All electrical outlets will be of the three prong grounded type, and I assume that lights are not grounded.

Anything that will be connected directly (not via outlet) that will need to be grounded?

The only things that come to mind are the air conditioners (indoor fan unit and outdoor compressor) and maybe the water pump as I don't know how that is connected (but I would assume via plug).

Third question:

What cable thickness do I need for the standard small stuff?

What on our list needs more substantial cabling and what thickness of cable is needed?

Fourth question:

What equipment on my list should be on separate breakers and what size of fuses should they have?

I have heard the shower heaters should be on separate 30 Amp breakers, and assume the air conditioners should also be on separate breakers, but what else (washing machines?).

Any suggestions as to how the "normal" stuff should be bundled on the breakers, or at least how many breakers I should have in our distribution board?

Fifth question:

What about lightning protection, is that something we should consider and if so how do you approach this?

Sixth question:

We haven't hired an electrician yet, and since the house is being build in a small village in the Mae Tha district of Lamphun province we will probably not be able to find someone truly professional (so maybe not much different to the rest of Thailand smile.png ).

Any suggestions for questions I can ask prospective electricians to ascertain that they are at least semi capable of doing the job to a safe standard? Should I just ask him some of the same questions I have been asking here and compare to the answers I am (hopefully) getting on this forum, or do you have other suggestions?

I know this is a lot of questions, and any input you can give me to any of the questions will be much appreciated. No doubt, any answers you give me will be met with a barrage of new questions from me smile.png

Thank you in advance for your time and effort.

Sophon

Posted (edited)

Of course, I forgot (at least) one question.

Seventh question:

Any ball park suggestions as to what would be a fair price to pay for such a job (labour only, I will buy the materials myself)?

Sophon

Edited by Sophon
Posted

Of course, I forgot (at least) one question.

Seventh question:

Any ball park suggestions as to what would be a fair price to pay for such a job (labour only, I will buy the materials myself)?

Sophon

With all these questions do you really think that you are qualified to purchase the correct materials ?

  • Like 2
Posted

OK first off you should go to your local PEA and ask them for the contact details for some actual electricians - usually they'll recommend an ex-staff member who started his own business, sometimes even a current employee doing some moonlighting - the point is if they work(ed) for the PEA, they have actual qualifications. If you want it done right, you don't want to use the guy that just laid your floor tiles, or smoothed your walls... ;)

1. A single load center with an RCBO instead of a main breaker will do the job.

2. Correct - AC's and water pumps are grounded - the latter usually via it's own copper rod, AC's via the normal supply.

3. Depends on how you're going to split up the circuits in #4, and length of cable runs from the load center to the load. Water heaters will want 4mm2 or 6mm2 and a breaker for each. AC's will likely only need 2.5mm2 and will want their own breakers as well. The rest you could probably split up into 5 more breakers: upstairs lights, upstairs power, downstairs lights, downstairs power, outdoor power. If using compact fluorescent or LED lights, 1.5mm2 should do, and for power circuits 2.5mm2 will normally suffice. You SHOULD have a proper electrician do the maths though.

4. see 3.

5. Protecting what exactly? You're not going to arrest a strike on the mains power. You can arrest strikes on phone wiring, but these days who uses that? ;)

6. See my opening remark.

7. Several factors in price, including the points raised in Q's 3-4 and the run from the meter to the house. Assuming it's a fairly standard 3 bedroom house, I'd say anywhere from 30K to 50K for all electrical work, sans parts.

  • Like 1
Posted

Have a look here for some answers: http://www.crossy.co.uk/wiring/

First question:
I want to have some kind of earth leakage circuit breaker that trips if something is wrong and saves our electrical equipment, but I have heard so many different terms used that I don't know what to ask for (ELCB/RCBO/RCD/Safety-cut etc.). Since we are under budget restrains I think one breaker for the whole house will be enough (but what do I know).
What (one) term should I use when I talk with our Thai electrician so that he will understand what I am asking for?


A front end RCBO is the way to go, all of the big name consumer-unit manufacturers do suitable devices which replace your main switch.

Second question:
All electrical outlets will be of the three prong grounded type, and I assume that lights are not grounded.
Anything that will be connected directly (not via outlet) that will need to be grounded?
The only things that come to mind are the air conditioners (indoor fan unit and outdoor compressor) and maybe the water pump as I don't know how that is connected (but I would assume via plug)


Most Thai installations leave the ground off lighting circuits, up to you of course.

Pretty well all fixed appliances require a ground.
Water pump is usually on a plug, if it's a bit remote run 2 core and put a local ground rod at the pump.

Third question:
What cable thickness do I need for the standard small stuff?
What on our list needs more substantial cabling and what thickness of cable is needed?


Put lighting on 1.5mm2 cable and 10A breakers.
Power outlet circuits on 2.5mm2 and 20A breakers (you can use 1.5mm2 for the ground wire).
Water heaters install 4mm2 on 25A breakers for up to 5,500W, 6mm2 on 32A breakers for up to 7,000W.
Most aircons will be fine on 2.5mm2 on 20A breakers.

  • Like 2
Posted

Of course, I forgot (at least) one question.

Seventh question:

Any ball park suggestions as to what would be a fair price to pay for such a job (labour only, I will buy the materials myself)?

Sophon

With all these questions do you really think that you are qualified to purchase the correct materials ?

So long as he gets the right answers, why pay a commission and risk a contractor buying junk to improve their profit? :)

Posted

Of course, I forgot (at least) one question.

Seventh question:

Any ball park suggestions as to what would be a fair price to pay for such a job (labour only, I will buy the materials myself)?

Sophon

With all these questions do you really think that you are qualified to purchase the correct materials ?

So long as he gets the right answers, why pay a commission and risk a contractor buying junk to improve their profit? smile.png

That's exactly the reasoning behind me buying materials myself.

I never said I was qualified to decide what is needed, but with the information I get here plus the advice given by our electrician it should be quite doable. It's basically just a question of buying myself what I have been recommended, rather than letting the electrician do it. That way there will be no financial incentive for the electrician to buy any particular brand or buy at a specific shop - or to pad the bill.

Sophon

Posted

Thanks for all the answers so far.

So in an attempt to sum up:

1. Earth leakage circuit breaker

  • I should ask for a front end RCBO, which will replace the main on/off switch.

If I understand correctly this device sits in the distribution board instead of the normal main switch.

2. Grounded equipment

  • Lights doesn't have to be grounded, but can be?
  • Water pump will be grounded via the plug (it will be located in a small room next to the carport together with filter and water tank, so no need for separate ground rod)
  • Air conditioners must be grounded (I assume both inside and outside units)

Is it recommended to ground lights? I have never lived anywhere where the electrics are grounded, so I really have no idea.

3. Cable thickness

  • Lights: 1.5 sq.mm.
  • Electrical outlets: 2.5 sq.mm (for ground wire 1.5 sq.mm will suffice)
  • Water heaters: 4 sq.mm (or possibly 6 sq.mm if we want to go above 5,500W)
  • Air-conditioners: 2.5 sq.mm

Is the 2.5 sq.mm recommended for A/C to be used for both inside unit and outside compressor?

4. Circuits and breakers

  1. Lighting circuit upstairs: Breaker size 10A
  2. Lighting downstairs: Breaker size 10A
  3. Lighting outside: Breaker size 10A
  4. Outlets kitchen: Breaker size 20A
  5. Outlets upstairs (excluding kitchen): Breaker size 20A
  6. Outlets downstairs: Breaker size 20A
  7. Water heater bathroom 1: Breaker size 25A (32A for water heaters above 5,500W)
  8. Water heater bathroom 2: Breaker size 25A (32A for water heaters above 5,500W)
  9. A/C bedroom 1: Breaker size 20A
  10. A/C bedroom 2: Breaker size 20A

For each A/C will both indoor and outdoor unit go on the same circuit and breaker (I assume they do)?

5. Lightning protection

  • We don't have any particularly valuable equipment, so it sounds like it may be OK to just protect computers and maybe TV with local surge arrestors

6. Hiring an electrician

  • The GF went to university in Chiang Mai (many years ago) with a guy who now works as a contractor. He will recommend some people that he has been working with for the job, and I'm quite sure that these guys will be qualified electricians not just handyman types. But from what I have heard here on this forum, in Thailand even being a qualified electrician doesn't necessarily mean all that much.

    I will ask them some of the same questions I have asked here, and if it doesn't work out I will keep the PEA angle in mind.

7. Labour cost for the job

  • Somewhere in the region of 30,000 - 50,000 baht (I am aware that there are many deciding factors, but I am just looking for sense of what we are looking at).

Is the above a reasonably correct summation of you answers, or have I misrepresented something?

Thanks again for your invaluable advice.

Crossy: Thanks for the link, I will try to read your site and see how much I understand.

Sophon

Posted

One more question that is kind of related.

I have yet to stay anywhere in Thailand, where the electrical outlets will have a firm hold on the euro type plug with two round and narrow prongs. Are there any brands of models of outlet sockets that can be bought here in Thailand that do a good job of holding on to this type of plug?

Sophon

Posted

Looks pretty good.

Yup the RCBO replaces your main switch.

Grounds on the lighting? If you have Class-1 fittings (have a ground connection) and they're within 3m of the floor then you should run grounds, nobody here bothers to be honest.

You only need to run power to one part of the A/C, there's a cable between them, we ran to indoor units.

If you get the good quality 3-pin outlets they do work with the thin Euro prongs but if you hang a power brick off them they soon get tired. I found some simple flat to round adaptors that fit the Euro pins but they tend to get a bit long. You can get the Schuko outlets that take both Euro and Schuko plugs, the proper solution but limits where you can plug in your Euros.

Posted

Looks pretty good.

Yup the RCBO replaces your main switch.

Grounds on the lighting? If you have Class-1 fittings (have a ground connection) and they're within 3m of the floor then you should run grounds, nobody here bothers to be honest.

You only need to run power to one part of the A/C, there's a cable between them, we ran to indoor units.

If you get the good quality 3-pin outlets they do work with the thin Euro prongs but if you hang a power brick off them they soon get tired. I found some simple flat to round adaptors that fit the Euro pins but they tend to get a bit long. You can get the Schuko outlets that take both Euro and Schuko plugs, the proper solution but limits where you can plug in your Euros.

Thank you for the prompt reply. Good information about the A/C internal/external unit being connected so only one needs to be wired, it does sound like the best solution to connect the internal fan unit.

Sophon

Posted

Under the question about cable thickness I forgot to ask about what type and size of cable I need for the distance between the meter and my distribution board. The distance is approximately 30-40 meter and the cable will be run underground. Also, do I need some type of special conduit to protect this cable?

Thanks again.

Sophon

Posted

Assuming a 15/45 meter you'll need to run 16mm2 NYY http://www.bangkokcable.com/catalog/BCC_CATALOG/NYY2EN.HTML

It can go direct in ground, but since there's no service fuses in Thailand I would put it in conduit, black with a red trace for electricity. Get it where you get the cable.

Get it as deep as possible, 500mm minimum and place some blocks above before back-filling to give the JCB driver a clue he's digging something up.

Posted (edited)

Looks pretty good.

Yup the RCBO replaces your main switch.

Grounds on the lighting? If you have Class-1 fittings (have a ground connection) and they're within 3m of the floor then you should run grounds, nobody here bothers to be honest.

You only need to run power to one part of the A/C, there's a cable between them, we ran to indoor units.

If you get the good quality 3-pin outlets they do work with the thin Euro prongs but if you hang a power brick off them they soon get tired. I found some simple flat to round adaptors that fit the Euro pins but they tend to get a bit long. You can get the Schuko outlets that take both Euro and Schuko plugs, the proper solution but limits where you can plug in your Euros.

Thank you for the prompt reply. Good information about the A/C internal/external unit being connected so only one needs to be wired, it does sound like the best solution to connect the internal fan unit.

Sophon

To be on the safe side, i would run the cables to the compressors via the internal fan unit with some excess slack for connection purposes, at both units.

Or, check with the a/c manufacturer that you will be using.

Reason being, not all a/c manufacturers have the cable between them, Daikin being one of them.

I found that the Panasonic brand of 3 pin outlets and light switches to be very good quality,

especially their "Wide Range"

Edited by sotsira
Posted

Looks pretty good.

Yup the RCBO replaces your main switch.

Grounds on the lighting? If you have Class-1 fittings (have a ground connection) and they're within 3m of the floor then you should run grounds, nobody here bothers to be honest.

You only need to run power to one part of the A/C, there's a cable between them, we ran to indoor units.

If you get the good quality 3-pin outlets they do work with the thin Euro prongs but if you hang a power brick off them they soon get tired. I found some simple flat to round adaptors that fit the Euro pins but they tend to get a bit long. You can get the Schuko outlets that take both Euro and Schuko plugs, the proper solution but limits where you can plug in your Euros.

Thank you for the prompt reply. Good information about the A/C internal/external unit being connected so only one needs to be wired, it does sound like the best solution to connect the internal fan unit.

Sophon

To be on the safe side, i would run the cables to the compressors via the internal fan unit with some excess slack for connection purposes, at both units.

Or, check with the a/c manufacturer that you will be using.

Reason being, not all a/c manufacturers have the cable between them, Daikin being one of them.

I found that the Panasonic brand of 3 pin outlets and light switches to be very good quality,

especially their "Wide Range"

I'm not even sure that we will be needing air conditioners, it depends on how cool the house turns out to be. We won't make decisions on brands until if and when we need them, I am just trying to prepare so that we don't have to run extra cables at that point.

Thanks for the tip about Panasonic outlets/switches, I will have a look at them.

Sophon

Posted

Reason being, not all a/c manufacturers have the cable between them, Daikin being one of them.

I've never come across a split type A/C without inter unit wiring (it would then need power to both units). I've checked a few Daikin installation manuals (here http://www.daikinac.com/content/resources/manuals/installation-manuals/split-systems/ ) they all have a 4 core inter unit cable.

Our sparks ran power to the indoor unit locations, many A/Cs (like our Samsungs) want their main power to the outdoor unit but it's not difficult to run along with the piping and inter unit cable when the system is installed.

Posted

On the AC wiring, many larger units need an outside safety disconnect while some smaller units use an indoor plug for the disconnect. Take a look at your local AC vendor for the units that you "might" want and plan accordingly. Its easier and cheaper to run the wiring now than to do it latter.

Posted

Reason being, not all a/c manufacturers have the cable between them, Daikin being one of them.

I've never come across a split type A/C without inter unit wiring (it would then need power to both units). I've checked a few Daikin installation manuals (here http://www.daikinac.com/content/resources/manuals/installation-manuals/split-systems/ ) they all have a 4 core inter unit cable.

Our sparks ran power to the indoor unit locations, many A/Cs (like our Samsungs) want their main power to the outdoor unit but it's not difficult to run along with the piping and inter unit cable when the system is installed.

I'm not sure, but i asked the Daikin installers where they wanted the power supply when

they were running the pipework.

They told me to run a supply to both the inside and outside unit.

This happened at two separate locations where Daikin's were being fitted.

Posted

Reason being, not all a/c manufacturers have the cable between them, Daikin being one of them.

I've never come across a split type A/C without inter unit wiring (it would then need power to both units). I've checked a few Daikin installation manuals (here http://www.daikinac.com/content/resources/manuals/installation-manuals/split-systems/ ) they all have a 4 core inter unit cable.

Our sparks ran power to the indoor unit locations, many A/Cs (like our Samsungs) want their main power to the outdoor unit but it's not difficult to run along with the piping and inter unit cable when the system is installed.

I'm not sure, but i asked the Daikin installers where they wanted the power supply when

they were running the pipework.

They told me to run a supply to both the inside and outside unit.

This happened at two separate locations where Daikin's were being fitted.

I've never seen a Daikin domestic AC that required a separate power supply to the outdoor unit - odd.

  • 2 months later...
Posted (edited)

Things are slowly progressing, and we are now nearing the point of having to buy the electrical equipment. That have brought up a couple of new questions.

What kind of connector do we need to connect the incoming supply to the main 16mm2 NYY cable leading to the house (buried in the ground)? Currently we have this medieval death trap installed by the workers:

post-5469-0-96790700-1382854369_thumb.jp

We have obviously asked for it to be boxed in to protect kids/buffaloes from accidental electrocution. I assume that when we install the permanent supply we will no longer need a breaker on the incoming supply (since we will have one in the distribution/breaker box), or am I wrong?

Second question is about the breaker box. is it recommended to buy an empty box and components separately or alternatively buy a finished product like these (from Global) with build in RCBO?

post-5469-0-04730900-1382858107_thumb.jppost-5469-0-30758300-1382858179_thumb.jp

Note that the first of these boxes come with a "Surge Protective Device". Is that something that are recommended?

Whether going for self assembly or the finished product, can anyone recommend brand and models, as well as where these can be purchased. We live in Lamphun, so have relatively easy access to Global, Thai Watsadu and Home Pro but any shop in Lamphun or Chiang Mai will do.

Thanks again for your help.

Sophon

Edited by Sophon
Posted

Hopefully you've left the NYY long enough to reach the meter position so you can simply strip off the outer sheaths and connect the cores to the meter (leave a loop of spare so you can re-terminate if necessary), no need for a breaker at that end.

If you need to connect to another piece of 16mm to get to the meter used barrel crimps (and the correct tool) insulted with several layers of 3M Jointers Tape.

As to your consumer unit, entirely up to you, if the ready made units have the right breakers for you then use one.

We bought ABB System proM units which come empty, you can then configure exactly how you want it with RCDs, RCBOs and MCBs as required.

I would install front end surge suppression, you'll still need arrestors local to your delicate kit, but the front end arrestor will take the sting out of the surge.

Posted

Hopefully you've left the NYY long enough to reach the meter position so you can simply strip off the outer sheaths and connect the cores to the meter (leave a loop of spare so you can re-terminate if necessary), no need for a breaker at that end.

If you need to connect to another piece of 16mm to get to the meter used barrel crimps (and the correct tool) insulted with several layers of 3M Jointers Tape.

As to your consumer unit, entirely up to you, if the ready made units have the right breakers for you then use one.

We bought ABB System proM units which come empty, you can then configure exactly how you want it with RCDs, RCBOs and MCBs as required.

I would install front end surge suppression, you'll still need arrestors local to your delicate kit, but the front end arrestor will take the sting out of the surge.

Thanks Crossy

I prefer to have everything clear in my head first (as far as possible), so we haven't even bought the cable yet.

The PEA installed a concrete pole on our land and pulled cable from it to the meter, which is on another pole on the opposite side of the road.

post-5469-0-95023700-1382864955_thumb.jp

post-5469-0-71763500-1382865055_thumb.jp

So the cable ends at the aforementioned breaker on our land on the pole on the left, while the meter is on the pole on the right. So connecting our cable directly to the meter would mean removing the PEA cable and somehow getting our cable to the top of the poles and across the road. I don't know if that is practical or not.

Where did you buy your ABB systems breaker box and did you also use ABB breakers? If I cannot find this brand, any brands to look for or avoid (or are they all more or less the same)? I believe I have seen Panasonic at Global, which I assume should be OK.

Sophon

Posted

Ah got it, you need to graft your cables onto the end of that cable across the road. The easy way is the barrel / butt crimps I suggested, your sparks should know how to connect. These http://www.thetoolboxshop.com/t050-pack-of-10-16mm2-cable-butt-copper-heavy-duty-tinned-terminal-1055.html

Our ABB kit came initially from HomePro, but our local electrical emporium also carries the breakers at much the same price (but rather closer). You should use the same manufacturer's breakers, but since the ABB boxes are DIN rail pretty well any DIN breaker will fit.

We had to use a Haco 50A incomer, PEA insisted that our ABB 63A was not acceptable on our 15/45 meter and ABB don't do a 50A 2-pole MCB.

  • 2 weeks later...
Posted

Crossey

I thought the 63A was the correct rating for the 15/45?

What was that all about?

Mike

Sent from my iPhone using Thaivisa Connect Thailand mobile app

Posted

Crossey

I thought the 63A was the correct rating for the 15/45?

What was that all about?

Mike

So did I, local PEA inspector thought otherwise, a small price to pay for a signed off certificate (he did no testing whatever).

Posted

We bought the NYY cable a few days ago, and had it buried in a 70-80 cm deep ditch. We needed about 80 metres and had a choice of paying 200 Baht per metre, or buying a roll of 100 metre for 16k Baht. Since the price would be the same I obviously went for the second option, which means we will probably end up with 20-25 metres left over. I guess we will just save that for later and maybe use it if we decide to run electricity to the well (although this cable would obviously be overkill for that purpose)

Sophon.

  • 4 weeks later...
Posted

We are now at the point where we are installing the electric conduits. No problem on the upper floor, as most of the connections will be in the attic space.

However, the lower floor consist of a raised crawlspace, that will be used for storage and for the dogs to sleep. Ceiling height is only about two meters (between the beams), so there is no room for a suspended ceiling. We will hide most of the electric conduits in the walls, but for practical reasons there are really only space to run a single ½ inch yellow round conduit around the room. So, how many cables can you reasonably run in one such ½ inch conduit?

The optimum would be to have separate cables for lights, outside lights and electrical outlets, so 4 wires of 1.5 sq.mm and 2 wires of 2.5 sq.mm. plus the 1.5 sq.mm. ground wire. If that is not doable then I can rearrange the distribution in the breaker box so indoor and outdoor lights are on the same breaker (and can therefore be on the same cables).

Also, is it recommended to use cables that consist of two wires, or is it better to use single wire cable (price-wise there is little difference)? It seems that even if using two-wire cables, the will have to be split up anyway much of the time to run the cable through switches etc. Or is it best to use a combination of single and two-wire cables?

Thanks again.

Sophon

Posted

I say 3 wires is the maximum to run through 1/2" conduit < 2.5mm2. There's probably some code for that but I think close enough. For wiring a house, you want single core, double core, etc. along with a plan. The plan will determine how much you need for whatever. Plan it.

Posted

+1 Steve

You'll wrestle to get that much into a 1/2" PVC conduit (it will just fit, but no room for that extra cable you always seem to need), there will be a de-rating factor for cables closely packed.

3/4" or even 1" is only slightly bigger and will carry 2x2.5 + 5x1.5 easily.

If it's all in conduit, singles are much easier to handle than sheathed cable.

Consider running 3/4"or 1" trunking rather than conduit around the room with conduit droppers, it's more work to install but far easier to get the cables in (and to add those extras).

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