Can I wire my Thai home to <insert name of country> wiring regulations?

[Crossy]

An oft asked question, particularly by us Brits.

 

Please feel free to comment on your home country regs, ask questions, whatever.

 

Let's keep it civil there is no "best" system every set of regs has it's own plusses and minusses.

 

On to the subject at hand

 

The general answer is "yes", most of the world's regulations (including Thailand) are based upon IEC 60364 

https://en.wikipedia.org/wiki/IEC_60364 

which makes an attempt to harmonise standards globally. Unfortunately, due to local historical effects it doesn't do a particularly good job.

 

I've started this thread for discussion of what you can and can't do here and where your home country requirements are unnecessary (adding cost) or potentially hazardous in the Thai environment.

 

It's important to understand that if you do decide to wire to BS7671, AS3000, US NEC or whatever you must do your whole installation to that standard, you can't cherry-pick the bits you like and ignore other parts, going down this route can lead to a hazardous situation.

 

I'll kick off with BS7671 (The IEE Regulations) used in the UK.

 

There are a couple of UK practices which could introduce a hazard if implemented in Thailand.

 

The Ring Final (Ring Main)

Beloved of us Brits along with the BS1363 fused plug the ring final was born out of necessity after WWII. The basic structure is a ring (odd that) of usually 2.5mm² cable which runs around the area to be supplied. Outlets are scattered at stategic points (never where you want them of course) around the ring. The ring is protected by a 32A fuse/MCB. In order to protect appliance flexes each plug has a smaller fuse (up to 13A) which will open long before the MCB thinks about it.

 

The problem here in Thailand (and most of the known universe) is that we don't have fused plugs! Implement a UK style 32A ring here and the bit of 0.5mm² speaker wire supplying your fan is "protected" by that 32A breaker. A short in your fan is going to have that wire melted and glowing well before the breaker operates (to be honest the 20A usually used on radials is going to be marginal too).

 

Also, the Thai outlet is (generously) rated at 16A, I don't really want to know what will happen at 32A plus when Uncle Somchai attaches his big welder! 

 

If you do have rings wired with Thai outlets why not break the ring at a convenient point and put each half on a separate 20A MCB? Less hazard and you gain an extra 8A of capacity!

 

The Main Switch

A UK Consumer Unit (distribution board) has a, usually 100A rated, main switch as incoming isolation.

 

This switch is just that, a switch, and provides no over-current / short circuit protection to the incoming supply and meter. In the UK said protection is provided by a fuse usually 60A or 80A (occasionally 100A) in the service head, this fuse belongs to the DNO (Distribution Network Operator) and is sealed. Blow it at your peril!

 

Here in Thailand there is no fuse provided by the network. There is nothing between your incomer and the transformer which may have a pretty large fuse. An average 150kVA "village" transformer is going to be fused at around 400A per phase on the LV side. Your 100A switch probably won't be happy and your meter may well be entering low-earth orbit if you get a short in your CU.

 

Your incomer should be an MCB or RCBO (for earth leakage protection if you don't have individual circuit protection) sized to suit the meter you have. Usually 50A or 63A if you have the common 15/45 meter.

 

[digbeth]

Getting colours to match the new Thai standards is a challenge, years ago it's Red White and Green, now it's black blue and green/yellow stripe for ground, most thai subcontractors who handle wiring just grab what they have left, wiring for three-phase colour complicates matter too

 

What exactly is inspected for when the utilities come and inspect your new home for connection? Anything goes after they've connected your meter right? What's the minimum that's required? even RCBO seems optional in Thai consumer unit

[sometimewoodworker]

29 minutes ago, digbeth said:

What exactly is inspected for when the utilities come and inspect your new home for connection? Anything goes after they've connected your meter right? What's the minimum that's required? even RCBO seems optional in Thai consumer unit

The RCBO is not optional neither is the earth rod, basically the inspection should involve the incoming supply size the earth rod and attachment and the main RCBO. 

 

However as has been mentioned in other threads inspections are extremely variable and may include a chat with the home owner/SWMBO quite a long way from the house.

[Crossy]

36 minutes ago, digbeth said:

Anything goes after they've connected your meter right?

 

Pretty much, once you have your permanent meter there's no further inspections. Of course if you cause a problem for the network they are going to come looking.

[Crossy]

I've posted this PEA document many times, once more wont hurt ???? 

 

Groundwire Mk2 book-Manual.pdf

 

The important diagram with translations.

Note the routing of the incoming neutral, you will need to do this to pass the MEA/PEA inspection.

 

[bankruatsteve]

Wiring my Thai house to the US NEC would be a supercilious attempt to prove that everything American must be the best.  Hey, I know some folks that actually believe that.  The one thing I don't personally agree with is main RCBO when there is proper earth distribution.  The NEC calls for RCD protection in bath areas and outside outlets which makes sense to me - everywhere else... aagh.

[Harry Black]

How about electric ovens? Overtime mine melted the socket here. In the UK i remember a special 13amp socket.

[Crossy]

Just now, Harry Black said:

How about electric ovens? Overtime mine melted the socket here. In the UK i remember a special 13amp socket.

 

If you have a 3kW (13A) or so oven I'd run a seperate circuit in 2.5mm² on a 16A or 20A breaker and hard wire it.

 

Theoretically you should be able to run it off an outlet, but ...

 

The smaller table-top beasties should fine on a (good quality) regular outlet.

 

Practice in the UK used to be to put a single 13A outlet on the cooker supply to feed the oven. Hard wiring via a fused-connection-unit on the cooker circuit is also common.

[Crossy]

7 minutes ago, bankruatsteve said:

Wiring my Thai house to the US NEC would be a supercilious attempt to prove that everything American must be the best.  Hey, I know some folks that actually believe that.  The one thing I don't personally agree with is main RCBO when there is proper earth distribution.  The NEC calls for RCD protection in bath areas and outside outlets which makes sense to me - everywhere else... aagh.

 

Works for me and would probably get you past Mr PEA.

 

UK now requires RCD protection on pretty well every circuit in a domestic environment.

[tjo o tjim]

1 hour ago, bankruatsteve said:

Wiring my Thai house to the US NEC would be a supercilious attempt to prove that everything American must be the best.  Hey, I know some folks that actually believe that.  The one thing I don't personally agree with is main RCBO when there is proper earth distribution.  The NEC calls for RCD protection in bath areas and outside outlets which makes sense to me - everywhere else... aagh.

I would beg (and have begged) anyone to not try to use the NEC in Thailand for oh so many reasons.  There are a few things we made a big push for in Thailand decades ago, like tamper-resistant outlets that make a lot of sense when using a high-impedance 120V wiring system and devices in a reasonably low-impedance 220V network. The lack of galvanic isolation for 220V loads is something I am still not a huge fan of, but trying to impose it here would be nonsensical. 
 

Grounding in the US is just so different (as a system) to Thailand that almost all parallels are moot. 
 

I would love to see NEC working spaces imposed on anything I built here though, as well as a few of the prescriptive requirements for branch circuits. 

[millymoopoo]

11 hours ago, Crossy said:

Let's keep it civil there is no "best" system every set of regs has it's own plusses and minusses.

It's a bit 'wild west' here in Thailand.

The PEA, or whoever your supplier is, are only interested in 2 things.

1: Getting the power to your meter, beyond that they don't really care much.

2: Getting the revenue that the meter generates.

By far the biggest issue here with domestic power supply is proper earthing.

Colour coding is somewhat irrelevant as long as the active, neutral and earth are correctly identified, and the cabling is of sufficient size to carry the load.

Whilst ring circuits do have good points, eg: plugs carrying fusing appropriate to appliance load, UK is out on their own there, and these days their disadvantages out weigh their advantages.

Far better to have multiple power circuits, max 16a loading and multiple lighting circuits, max loading 8a.

Of course all protected by earth leakage circuit breakers, one or two for power, lighting may be included on one of these, and a separate one for the hot water.

But definitely connected to proper effective earthing.

Earthing is your 'safety watch it' .!

As is RCDs (residual current devices) safety switches.

Thus I would suggest, wire up the house with many circuits with small loads, then if the need arises you have the capacity to add more to any circuit.

Then if a fault does develop you loose only one circuit, whereas on a ring feeder you loose everything beyond the fault, if not the whole ring.!

And do ensure you have good earths, multiple earth spikes in and around wells. soaks and septic tanks, (permanently wet areas) all linked together.

 

[JBChiangRai]

Every Thai electrician will tell you that electricity is completely different in Thailand, and no earth is required

????

[Crossy]

4 minutes ago, JBChiangRai said:

Every Thai electrician will tell you that electricity is completely different in Thailand, and no earth is required

????

 

Yup.

 

Even when the appliance says (in Thai) "this appliance must be earthed!"

[Muhendis]

4 minutes ago, Crossy said:

Even when the appliance says (in Thai) "this appliance must be earthed!"

Because it comes from Japan/China/South Korea/anywhere else, the earthing requirement cannot possibly be as good as the village standard regime.

[bankruatsteve]

C'mon. Not "every Thai spark" believes that. The sparks that come from homes built out of wood and on wood poles are correct. No need ground. 

[PaoloR]

Went out today to by a new plug.

2 local hardware shops -no 3 pin plugs.

Drove half an hour to Home Pro - no 3 pin plugs.

Ended up ordering from Lazada.

This for me sums up the approach Thailand has to electrical safety.

[Muhendis]

22 minutes ago, PaoloR said:

Went out today to by a new plug.

2 local hardware shops -no 3 pin plugs.

Drove half an hour to Home Pro - no 3 pin plugs.

Ended up ordering from Lazada.

This for me sums up the approach Thailand has to electrical safety.

Your next task will be to find a 3 pin socket for you Lazada plug

[mahjongguy]

I like these:

https://www.lazada.co.th/products/i1085314162-s2456612475.html?urlFlag=true&mp=1&spm=spm%3Da2o4m.order_details.item_title.1

 

I also buy the female equivalent to make heavy duty extension cords.

https://www.lazada.co.th/products/i1085354266-s2456678374.html?urlFlag=true&mp=1&spm=spm%3Da2o4m.order_details.item_title.1

 

[RocketDog]

14 hours ago, JBChiangRai said:

Every Thai electrician will tell you that electricity is completely different in Thailand, and no earth is required

????

Earth Ground will soon be replaced in the Kingdom by Space Ground.

It's one of the many revolutionary spinoffs soon to come from the aggressive Thai Space Program and upcoming Moon Mission.

 

Sell all your stock in ground rod companies.

You've been warned.

[brianthainess]

On 11/19/2021 at 6:38 AM, Crossy said:

I've posted this PEA document many times, once more wont hurt ???? 

 

Groundwire Mk2 book-Manual.pdf 803.56 kB · 4 downloads

 

The important diagram with translations.

Note the routing of the incoming neutral, you will need to do this to pass the MEA/PEA inspection.

 

I would like to add if you run any cable from the meter now to the property, all connections must be clamped together and not taped, any underground cable to the property can not be the same as above ground, it must be a twin heavy (double)duty insulation and in the yellow PVC tubing/pipe.

[SAFETY FIRST]

On 11/19/2021 at 5:53 AM, digbeth said:

years ago it's Red White and Green, now it's black blue and green/yellow stripe for ground

Isn't that the European standard colour code

Australia went the same way. 

 

On 11/19/2021 at 5:53 AM, digbeth said:

most thai subcontractors who handle wiring just grab what they have left

The Americans do the same thing. 

I've seen them use red as earth. 

[Led Lolly Yellow Lolly]

Technically, with some regs it's possible to use any colour as the CPC conductor BUT you must mark it with some green tape at both ends. Personally I frown on the practice.

[Artisi]

On 11/19/2021 at 5:15 PM, JBChiangRai said:

Every Thai electrician will tell you that electricity is completely different in Thailand, and no earth is required

????

My thoughts exactly, you beat me to the comment. 

[Artisi]

On 11/19/2021 at 5:38 PM, bankruatsteve said:

C'mon. Not "every Thai spark" believes that. The sparks that come from homes built out of wood and on wood poles are correct. No need ground. 

Not too sure about that, wet bathroom floor, wet waste water pipe sounds like a hazard to me, but then most Thai drains run up hill so that might cancel the path to earth ????

[Led Lolly Yellow Lolly]

On 11/19/2021 at 4:40 AM, Crossy said:

An average 150kVA "village" transformer is going to be fused at around 400A per phase on the LV side

Biggest I use is 160 amps, although one of our transformers is 400kVA the fuses never blow on it. I have boxes of them in my drawer (see my picture). Sometime I'll ram them into circuit and if there is a direct short somewhere causing the blows the arc can be pretty spectacular. I sure WOULD NOT want 400 amps shorting in my CU. I'll always deploy a screw mounted breaker on the pole, it's useful isolation for routine work and good protection for the scenario you mention.

 

 

Edited November 21, 2021 by Led Lolly Yellow Lolly