A power cut is a power cut, is a power cut?

[Morakot]

A bottle of the finest Gewürztraminer for each of you learned gentlemen.

My head is still spinning, grappling with the foundations of three-phase electric power.

[Crossy]

I really don't want to go into the nitty-gritty of 3-phase here, there are plenty of references on the net which are far better than I could explain.

But, as a starter for your searches:-

Thai High Voltage distribution (the large insulators on the tall poles) is 3-phase, 3-wire (or delta connected), there is no neutral at this point.

The Thai Low Voltage or house current (small insulators on shorter poles) is 3-phase, 4-wire (or star connected, some may know it as wye or Y) derived from the HV via a transformer. Often these wires are on the same poles as the HV when running beside the road.

Single-phase (220V) supplies are taken between one of the three phases and the neutral, if you have 3-phase you effectively have three single-phase supplies, and, unless you have 3-phase appliances, it's best to treat it like that.

[Naam]

A bottle of the finest Gewürztraminer for each of you learned gentlemen.

My head is still spinning, grappling with the foundations of three-phase electric power.

as Crossy mentioned, just look at it and treat it as having three indepent single-phase supplies to your home. i have 2 gadgets in my home which use "real" 3-phase but only because my builder did some sh*t behind my back.

however i need the amps the 3-phase connection provides. but the latter will not stop the fairy tales "3-ph commercial only" and "house electric single ph only".

[Naam]

My answer was for Thai forum. Last lived in Germany in 1968 - memories are more of very fine wine.

misunderstanding! my answer was meant for the Right Honourable Sir Gandalf from (i think) down under.

[Naam]

and now we are waiting patiently till Morakot serves the Gewürztraminer

[Shiver]

Well I learned something today. I thought home power was to take one phase from a 3 phase for load balancing, not a shared supply like an industrial or hotel type scenario.

I find that when power goes out it is usually 1-2 hours (the guys that fix these things are usually pretty snappy, despite the flipflops and bamboo ladders - which aren't such a bad idea when you think about it). Unfortunately it always seems to be outage on the hottest day of the year and it's too early to go 'socialise' - no internet, no tv, no fan, no aircon...arghhh! what to do with my broken life?

Maybe some kind of UPS device might help, but my own experience of them is less than great. I've had a couple and they just don't do what it says on the tin.

Thailand LV is (mostly) 3-phase 4-wire with domestic coming from one phase and the neutral, but the HV supply is 3-phase 3-wire (no neutral) so a phase lost at HV causes some interesting effects on the other side of the LV transformer.

The best solution if you get long outages is a small genset, if you get one of the 'silent' diesels with auto-start you may not even notice the outages.

You'll still need a UPS on your PC (unless it's a laptop) to bridge over the time the genset takes to start, ours is online in 30 seconds or so. We also have a UPS on the TVs and some lights so we are never plunged into total darkness and we can survive a night without the noise of the genset.

Info appreciated. Next time there is an outage might be the one that pushes me over the edge to actually do something about this and make it go away. It's easy to ignore until it happens again, then it becomes the most important thing in life! (though a simple life would make a lot more sense).

[Morakot]

and now we are waiting patiently till Morakot serves the Gewürztraminer

Forgive me, my dear man Naam, the cellar master has just informed me replenishment of our stocks is continuously hampered by local Custom officers. There is good news though. My local microbrewery on Ko Kret will soon have another batch of craft-beer ready for collection: English-style top-fermented (obergaerig) pale ale.

The Thai Low Voltage or house current (small insulators on shorter poles) is 3-phase, 4-wire (or star connected, some may know it as wye or Y) derived from the HV via a transformer. Often these wires are on the same poles as the HV when running beside the road.

Single-phase (220V) supplies are taken between one of the three phases and the neutral, if you have 3-phase you effectively have three single-phase supplies, and, unless you have 3-phase appliances, it's best to treat it like that.

Thanks Crossy, good man! This makes at lot of sense.

[Litlos]

I bought a 4 slot din box at Watsadu. Ok my use was installing 4x din surge arrestors to try and stop the local lightning surges (8 months and no problems by the way). I think they sold them as mini switchboards for apartments. Was 200 or 300 Baht.

Why four surge arrestors? Did you put the DIN box after your main box?

What's the going price for a DIN rail surge arrestor, if you don't mind saying?

The four surge arrestors are one per phase to earth plus one on the neutral to earth. Really cannot trust the neutrals here to be properly earthed. I simply tied the feeds to the surge arrestors into already used by AC breakers at the top of the board closest to the incoming breaker. There should have been spare slots until the numbnuts PEA got involved.

I think I paid about USD100 for the four, but I did a deal with a guy I work with who is from the USA, so that is USA pricing. Note I still use surge arrestor power boards on anything expensive for double protection.

Cheers

[Litlos]

If you are interested talking about this reminded me that I probably should get a spare set of surge arrestors and found this from RS in Singapore (in English), then plugged the same part number into the Thai RS site and voila. ABB is a well known brand. As I cannot paste into Thaivisa for some unknown reason google "RS Online Thailand" and search for 701-8749.

This is for three phase but could be used on single phase. One of those quirky things where the bigger 3 phase unit is cheaper than a single phase unit.

Cheers

[Crossy]

If you are interested talking about this reminded me that I probably should get a spare set of surge arrestors and found this from RS in Singapore (in English), then plugged the same part number into the Thai RS site and voila. ABB is a well known brand. As I cannot paste into Thaivisa for some unknown reason google "RS Online Thailand" and search for 701-8749.

This is for three phase but could be used on single phase. One of those quirky things where the bigger 3 phase unit is cheaper than a single phase unit.

Cheers

701-8749 is the replacement cartridge only

The complete single and 3-phae units are 701-8714 and 701-8733 $$$

[Morakot]

Thanks Litlos! My house is in a built-up urban area. Not sure if I'd really need surge arrestors. I have protected some important devices at the point of connection.

What do other people do here?

[Morakot]

The complete single and 3-phae units are 701-8714 and 701-8733 $$$

I have to say that site is not cheap, but it looks really like high-end, quality products they are selling.

http://th.rs-online.com/

What's the Chinese TOMZN brand like, you recommended?

[Crossy]

The complete single and 3-phae units are 701-8714 and 701-8733 $$$

I have to say that site is not cheap, but it looks really like high-end, quality products they are selling.

http://th.rs-online.com/

What's the Chinese TOMZN brand like, you recommended?

RS have never been cheap or even low-cost.

The Chinese stuff seems to work. We had one cartridge indicate red after a nearby strike and we lost no electrical kit so it evidently did something. As to just how near the specified ratings they really are, who knows.

We have multiple small MOVs scattered around too so not relying on a single unit.

[lopburi3]

One thing to remember - believe Crossy had a strike on his brand new home (after living a life of generator power for a long long time) after the flooding - so expect he is, understandably, a little gun-shy in this regard - and he also has the knowledge of how to protect.

My home in same region was bought some 42 years ago and has never been hit by lightning and the only damage from local strikes have been a few phones (they were on TOT line with no ground). So expect the real odds are not that high for serious damage bills. But as any insurance it can protect you in the off chance.

[Crossy]

Gun-shy? Possibly

The surge protection would not have saved the roof or SWMBO's teak barge board, but it surely would have reduced the electrical damage we suffered.

These little 8kA MOVs are 10.5 Baht each at NPE. A big bag scattered around can't do any harm.

http://www.mynpe.com/mynpe/more.php?data=116450101022&quantity=1&c=class2

[Litlos]

If you are interested talking about this reminded me that I probably should get a spare set of surge arrestors and found this from RS in Singapore (in English), then plugged the same part number into the Thai RS site and voila. ABB is a well known brand. As I cannot paste into Thaivisa for some unknown reason google "RS Online Thailand" and search for 701-8749.

This is for three phase but could be used on single phase. One of those quirky things where the bigger 3 phase unit is cheaper than a single phase unit.

Cheers

701-8749 is the replacement cartridge only

The complete single and 3-phae units are 701-8714 and 701-8733 $$$

Right you are, good catch. Used to be able to trust RS as well. Picture is wrong, description is wrong as well.

Will have to look for some other alternatives as I lost my contact in the US due to oil field layoffs.

Cheers

[Morakot]

Crossy, if you don't mind me saying, that ridge of your needs some urgent attention. It will save you a fortune, not having your roofer redoing all tiles when its too late. If a gust gets under the crown tiles, you could end up with no roof left.

[Crossy]

Crossy, if you don't mind me saying, that ridge of your needs some urgent attention. It will save you a fortune, not having your roofer redoing all tiles when its too late. If a gust gets under the crown tiles, you could end up with no roof left.

Thanks for the concern, that photo was taken in 2012 immediately after our lightning strike. The tiles blown off or damaged by the hit were replaced the same day

Cost a massive 2,500 Baht all in.

[Morakot]

butt-splicing an extra length to the tails, proper crimps are a simple, safe and permanent solution when combined with heat-shrink (not tape).

I'm ordering the last pieces to get the additional DIN rail box set up. I am still not clear about the standard sizes of wires and crimp connectors I need.

Looking at this US conversion table and it says gage 9 (2.90576mm diameter) is required for 64 A.

What is the Thai standard for copper diameter and amps? What crimps do I need for 63 A and less?

Thanks!

[Crossy]

THW from Bangkok Cable http://www.bangkokcable.com/product/backoffice/file_upload/131004_1-450!750V%2070C%2060227%20IEC%2001%20%28THW%29.pdf 10mm² is rated at 67A in air but you might want to go to 16mm².

But, it can be a bit of a wrestle in a confined space.

IEC 60227 http://www.bangkokcable.com/product/backoffice/file_upload/131004_2-450!750V%2070C%2060227%20IEC%2002.pdf has more strands of finer wire and is more flexible / less of a wrestle. But it's less common, I've only seen it in specialist outlets and you'll need 16mm².

Get crimps to suit the wire size you have, you'll need a tool too. That said, the tunnels on the DIN accessories will take the cable naked.

EDIT Fixed the links.

[Morakot]

Thank you so much Crossy!

[Morakot]

It was asked earlier on in this tread how common these type of power cuts are here in North Bangkok. The photo was taken last week and the outage lasted for 45 min. But this time we had around 160V instead of 50V, mostly throughout the entire outage.

Interestingly, one of the neighbours phoned the provider about how long the cut will be. She was "reassured" with 'soon' and shouldn't worry, as she can use the low voltage for the time being.

[lopburi3]

That 160v is common when you are on a good phase and fuse has blown on another - even enough to operate most lights these days.