Led Lolly Yellow Lolly

4 hours ago, Crossy said:

OK. I have actually seen CUs here with no ground bar.

 

The housing project that my family took over a few years ago, NONE of the CUs had ground bars. All of the CUs are SquareD Classics, so I know the ground bars were there when they were fitted. The only thing I can come up with to explain it is the spark that fitted them decided that as none of the receptacles had three pins, and no CPCs were used, he just unscrewed them and tossed them into his recycle bucket for the recycle value.

Incidentally, the Thai for ground bar is 'bar ground'. . . and they say it's a hard language to learn!

Further to the above, my wife just emailed me this link for you. . .

http://zeekway.com/news-department-of-skill-development/

I respect what you're saying of course, but these things aren't exactly gazetted to the general public. This new legislation has been boiling for years and unless you're connecting new meters every week it's entirely understandable you won't know about it. You won't find much about it on the PEA website as it far broader than just some new rule the PEA might conjur. In order to be certified you have to sit a test at your local Ministry of Labour (the issuing body). I just asked my wife to dig something up for you, so you can have fun reading through the PDF documents listed here. . .

http://www.dsd.go.th/oloc

The only reason I know about it is because we have someone that attends regular meetings at the local PEA office. She supplies us with around 2 kilometres of 16mm copper cable every year, not a small amount of money so I have a pretty good working relationship with her. She's actually the only person I've met in Thailand that fully understands a Multiple E/N system, but that's by the by. We also have a PEA subcontractor that comes to replace popped fuses on the low voltage side of our transformers, if he's willing I'll ask him if I can scan his certification to post it here. There are different levels of certification, this guy I mentioned is not allowed to touch the other side of the transformer, higher voltages = different certification level or different level of permission from the PEA, so we have to call someone else if our expulsion fuses pop.

I assure you that starting from September last year, you will not get a new meter connected unless the electrician wiring the building has been certified, and you are fully protected with RCBOs, certainly not in my neck of the woods. Slowly, glacially slow, they are getting their act together.

Various RCBO devices are now much easier to come by. Just a couple of years ago I found it very difficult to source single pole RCBOs, now you can easily find them in Watsadu, HomePro, Global House, even independent electrical retailers. No doubt this is due to the sudden and increased demand by the new regulations I mentioned before. Regarding certifications, the PEA will not 'pass' any new builds unless the electrician (I use the term deridingly) can show his certification card.

Unfortunately I don't have a link but your local PEA office will confirm. On a related note, electricians are also now supposed to be certified. Yes, I know certifications are all but meaningless here, but it's another move in the right direction.

8 hours ago, r136dg said:

No front to back protection, no meter?

I really have no idea how you extrapolated that from my post.

Yes it's for real, nationwide.

On 03/03/2017 at 3:24 PM, bankruatsteve said:

Ants and other critters don't usually bother these things but it wouldn't surprise me.

I had a single pole Schneider RCBO fail on me just a couple of weeks ago. The ants got into the device in sufficient numbers to set fire to themselves. The RCBO tripped, but not due to L/N imbalance, I think it was short current. After replacing I gave the failed RCBO a few hard taps on the table and out came all the cooked ants. The RCBO now works again, but I'll probably bin it anyway.

On 02/03/2017 at 6:42 PM, Crossy said:

Official answer.

No problem with VAF in conduit although it may need de-rating slightly, but no way it should go anywhere it may end up in standing water.

VAF cable, particularly cheap brands that are everywhere here, quickly become hygroscopic, to the point it doesn't need to be submersed. I had a real headache tracing an earth leakage on an air conditioner a couple of years back. Turned out to be VAF cable running alongside the condensation drain leaking current to the grounded coolant pipe. Personally I wouldn't advise anyone to leave VAF cable in the ground, it's just a matter of time before it gives you problems. Buried cables need to be NYY, >60 centimetres below the surface in high density polyurethane pipe and covered in concrete. This will last for a hundred years. I'm working on a project right now where gardeners are digging through live THW cables just 2 inches below the surface. Their spades just slice straight through the conduit (wooden handles, fortunately). Waste of time if it's not deep, and concreted. As this company is finding out to their cost, they all need replacing.

On 19/03/2017 at 0:07 PM, Crossy said:

Sparkies here tend not to understand RCDs and RCBOs, period.

The lack of understanding aside, their confusion is somewhat reduced by a change in the law that came into force at the end of last year. All new builds must now be fully RCD/RCBO protected.

I have a Time Domain Reflectometer on a couple of my enterprise grade LAN switches, this model being one of them. . .

https://www.ubnt.com/edgemax/edgeswitch/

Indeed, this is a really great feature set for finding where a rat had his plastic lunch, but this is not what I have in mind, it's just a simple pocket device for sending a shrill signal into a wire so you can use the other pocket device to follow it through walls.

I could probably get the budget to stretch to 17,000. How does this model look?. . .

http://th.rs-online.com/web/p/insulation-testers/9214517/?origin=PSF_436991|alt

With one of your above links, I found this dandy looking Fluke device. . .

http://www.es.co.th/detail.asp?Prod=006102485

Honestly I'm sick of rolling out my 80 metres of botched together bits of tangled spaghetti spare wire to test which wire is which, it's a 30 second job with a 'pinger' probe. I've been doing the electrical stuff here for years now, why I want to start investing in some proper kit to ease the pain. Oh the pain.

Thanks, me somewhere to start looking.

While we're on it, I don't know what the devices are called, and I've never seen them in any shops here, but it sends a 'ping' down a cable so you can use a related device to trace the cable. They're often used in telephony, but I want one for easy identification of unmarked live/neutral tails from a meter.

Also, there is a device that senses voltage in a cable simply by waving it over the cable. What are they called and where can I find one?

I need to purchase a device that can perform basic insulation integrity tests on buried cables, as well as final circuits. If it can do Ze and ground rod resistivity checks too that's a bonus, but the important thing is insulation testing.

I won't be able to get authorisation to spend thousands of Dollars on a 'do everything' Fluke device. Obviously if I can get something from Fluke or Megger that's nice but I'm open to suggestions. Where can I get this in Thailand, do you have any basic models to suggest?

When the technicians cut the supply, be sure to verify that fact yourself, and while working, be always aware the power could come back on when the 'techmicians' decide that you've had long enough to do the job.

Of no help to you, but helpful to readers with DIN mounts, ABB do some nice 2 pole RCD devices. I have one in my house. Theses are not RCBOs though, so you'll need separate overcurrent device alongside it.

That's not what I said. I said I've been advised that's what the PEA want. I'm saying this is likely poor advice, as THW cable should never be used exposed to the elements, especially where it can come into human contact.

Rooms are around 46 Sqm, so 24,000 is still a little on the low side. In this price bracket, customers will expect rooms to cool well and cool fast.

Hi, thanks again for chiming in. Indeed, at ~2400 Baht a pop, I'm not inclined to replace all of the RCBOs. Taking a closer look at my wife's handwriting, it's seems the showers are not 8000 watts, but actually 6000 watts, so based on your guidance, I think we should be OK, although there's still not much room for a kettle being plugged in, or similar.

10 amps for the aircon though, that sounds a little lean. I'd have guessed more like 15 amps, but I'm not sure. Cable is 4mm with a 20 amp breaker as it stands.

I'm actually surprised at the current carrying capacity of the NYY. According to the Bangkok Cable specs sheets, this appears better than THW cable of the same size, but I may have read this wrong.

On a semi-related note, my local electricals supplier insists I cannot use NYY cable for the drop from the overhead cables down the pole to the load centre mounted on the same pole. She insists I must use THW cable for that, according to PEA rules. This sounds odd to me, I'd have thought it would be the other way around. I plan on using NYY cable anyway.

We're building some new bungalows for guests. Somewhere along the line room sizes and cable sizes got all mixed up (Thai style planning etc etc). The bungalows are supplied by 10mm sq NYY cable in conduit underground. There is no way in hell these cables are coming out for replacement. We originally planned for 12,000 BTU aircon but I've looked at the figures and realised this is woefully inadequate for the size of the room. 24,000 BTU is what's required.

Complicating the situation further is I've seen 8000 watts as the specs for the showers!

I've got 40 Amp RCBOs protecting the cables. I'm concerned. I could probably get the specs for the showers reduce to a 6000 watt model. It MAY be possible to get away with 18,000 BTU aircons. How am I looking here for the 10mm cable?

Thanks for the link AJ but I'm nowhere near Bangkok. Frankly I don't think I'll ever find anyone here that takes any pride in what they do. If I walk around our local Central shopping mall and look up, I can see equipotentially bonded steel wireways, and what looks like a pretty good job at that. So I know, I KNOW there is someone here that can work to basic electrical standards. . . but I've no idea who or where they are. Lord knows I've tried to find them.

On 9/13/2016 at 5:13 AM, Crossy said:

When the 22kV drop fuses pop out I assume you call PEA to put them back?

Yes, they charge us something like 250 Baht to come and re-arm the fuses a shove them back in. Free of charge if they popped on their side. The cost is nothing, the issue is it takes hours for them to come, and this is a problem if we have a full hotel (we have no backup generator). This is one of the reasons I've been considering investing in a set of hot sticks, the risks involved with that, and any regulatory considerations.

As a side note, it always seems to be the same phase that pops out, I'm not sure why. When that happens, it's worthy of note that there is still voltage on the final circuits, I know this because all our LED lights stay illuminated (they will work on less that 100 volts) but the flourescents go out along with everything else. I've measured the voltage during such an event and it fluctuates wildly between ~ 70 volts to ~120 volts while the phase is out. I've not yet had had a good explanation as to why this is the case.

If you're interested, drop me a PM and I'll give you our location. I'll also post some pics when I have time, it would sure be good to have someone else interested in what I'm having to deal with.

Sure I expected you to highlight the dangers of high tension lines. I can tell you that anything over 50 volts scares the bejeebies out of me, so just looking at a transformer from afar is sufficient to give me night terrors. There is a retired PEA worker in a nearby village. He's easily identifiable, his arm was blown off at the elbow and he walks with a heavy limp, presumably because that's where the current exited. He was forced to retire when he somehow put himself across an energised high tension line. By some miracle he survived that.

What I'm getting at is that I don't trust the PEA or any contractor to sufficiently isolate the supply before I work on the systems. I've been here for 15 years and have seen enough to know that those that should be competent, are not. For example, they think it's OK to shut down one phase to work on it while leaving the other two phases live. This kind of mai bpen arai attitude is completely incompatible with me.

Another thing is the expulsion fuses regularly pop out on our transformers. For whatever reason, we have a lot of tree snakes here and they appear suicidal. Their chosen method of ending their lives is 22,000 volts. So, when I work, I want the expulsion fuses OUT. . . . AND the fuses on the low voltage side. My reasoning it that will protect me if a tree snake crosses that gap left by the expulsion fuse while I'm working on the circuits. To summarise, I'm terrified of the transformers, healthily so, but I'm confident in the physics, and confident enough to isolate myself from the dangers. I'll be seeing if I can find someone to do what I want and expect though.

About the MEN link, this is what I was angling for. I'm not sure if I should link at the outdoor boxes or the CUs in the bungalows. Labour wise, it would be more time efficient to link in the three phase boxes outside. If I'mm TTing the whole shebang, is there anything to lose by adding the MEN link. I guess I need to get the presence of a MEN system properly verified. I've measured the voltage between ground and Neutral everywhere, all at 0 volts, so it's looking good.

Meter is high voltage, and placed at the demarcation point between our private system and the public side.

Something for Crossy et al to get your teeth stuck into. . .

My wife and I operate a series of resort bungalows on a large area of land. We have our own private high voltage system (22,000 volts) supplying our 4 privately owned transformers. From those transformers, the low voltage three phase side is distributed to the bungalows.

I've been examining what the spark did prior to us taking over. As expected it's a train wreck. THW cable buried a couple of inches underground, vague earthing, inconsistent earthing, you know the routine. I'll be sorting this out by myself, I can't find a competent electrician. It's a major undertaking and is costing bags of money, so I want to get it right. The job will also be putting me face to face with live transformers with hot sticks. My working practices have to be flawless as a result.

The way the low voltage has been distributed to the bungalows it a bit odd. Blocks of six bungalows are being supplied from three phase load centres mounted on power poles outside. These load centres are the means of remotely isolating each bungalow. Each bungalow has it's own consumer unit inside. I have already fitted RCBOs throughout the resort as an urgent measure.

As I understand it, the PEA installed our private high voltage system and transformers. However, I have not yet been able to properly verify the presence of a MEN system. None of the bungalows have MEN links, nor do any of the three phase load centres supplying each block of six bungalows.

Assuming the MEN system is implemented on our land, I propose to do the following. . .

I am replacing the load centres on the power poles outside and putting them in IP65 enclosures. Each of the six bungalows will have an individual single pole breaker, balanced accross the three phases (two bungalows per phase). There will be a three pole breaker that can isolate all six bungalows. I will install a MEN link in these three phase load centres that supply each block of six bungalows, with 16mm cable between ground bar and neutral bar. I will drive a ground rod at each of these outdoor load centres and connect to the ground bar in that load centre. If I understand things correctly, even through theses three phase load centres are outside, we can pretend they are in a main building, and the individual consumer units in each bungalow can be considered a sub-panel. There will be two core NYY supplying the bungaows, so I will make them TT systems (they already have RCBOs and their own ground rods).

As far as I'm aware, this is acceptable and safe, but I'm not confident enough and need some input from the experts here.

Thanks. For the record, I've actually made this a TT system, as I can't verify 100 percent that we have a MEN supply (we're way, way out in the sticks, no village, just the family house). I asked the local PEA chap but he didn't appear to know either. If it is later established for sure to be a MEN supply, it's a trifle to add the link later, and my ground connection is 16 mm to match the incomer/tails. I can see neutral connections to ground on the pylons that run along the road, but I just feel safer with a TT system for now.

Thank so much for taking the time to comment.

Do you think I've downgraded enough, or should I go further? There will never be much current on any of these circuits, I could potentially go down to a 10 amp breaker even on the plug circuits. Overkill?

Oh and one more question to add. Is there anything in the Thai rules that says I can use a CPC/Earth conductor one size smaller on final circuits? (I have RCBO fitted on main incomer). For example........

Live 6mm, Neutral 6mm, Ground 4mm

and

Live 4mm, Neutral 4mm, Ground 2.5 mm

etc etc???

I've not read every post, so sorry for any repetition, I just want to get ot the point. . . . .

I can confirm 3M resin splicing kits are available in Thailand, I've ordered them and used them before.

Regarding your cable, if it's not Steel Wire Armoured cable, it is NOT suitable for direct burial. The way I did it with my houses, so far four times, was to use 16 mm NYY cable, 25 mm in one case actually. I fed this through HDPE conduit (High Density Polyethylene) buried 60 cm underground. Before backfilling with soil, we poured 5 inches on concrete around it.

I expect this arrangement to last at least three times as long as the house, as long as the cable is never overloaded.