Depth of Underground Power Supply

[cdmtdm]

does Thailand have a regulation on how deep any underground power supplies should be ? basically overhead from the street to a pole on the front boundary , then underground to the house approx ...20 metres .... i think the contractor is telling me a porky pie !!

[cooked]

I guess nobody knows. I would put it at least 60cm deep in the special electric conduit pipes, plus a red and white band laid along the top so that if the ground should should get disturbed there in the future, there is a warning. This means that site surveillance would be necessary.

[Crossy]

Yeah ^^^, 50-60 cm would meet most regulations globally so would be fine here and would keep it out of the way of normal gardening activities.

You could get away with 30-40cm if under your driveway or path.

Place some lean mix concrete (just sand and cement) on top of the tube before backfilling.

Make sure you use cable rated for damp locations even if you run in conduit, this is the stuff you need http://www.bangkokcable.com/catalog/BCC_CATALOG/NYY2EN.HTML

[AnotherOneAmerican]

They just did my house, beside the concrete drive, cables are about 1" under the soil, water too.

[Pib]

They just did my house, beside the concrete drive, cables are about 1" under the soil, water too.

One inch down ain't much....but I guess it makes reaching the lines easier/quicker in case of needed repair. But I sure hope the next fellow in your house knows that in case he ever needs to dig there, drive something into concrete an inch or so, etc.

[Deke]

The actual requirement is 60 cm for direct burial cable and 45 cm for cable in most types of conduit. It can be reduced to 15 cm if rigid steel conduit is used.

The reference standard is มยผ. 4502-51.

[Pib]

The actual requirement is 60 cm for direct burial cable and 45 cm for cable in most types of conduit. It can be reduced to 15 cm if rigid steel conduit is used.

The reference standard is มยผ. 4502-51.

Good info. Here's a link to the reference standard (I think) but it's in Thai and google translate can't deal with the particular format used at the link. Any idea if there is an English version (official or unofficial) anywhere on the web?

[Deke]

The actual requirement is 60 cm for direct burial cable and 45 cm for cable in most types of conduit. It can be reduced to 15 cm if rigid steel conduit is used.

The reference standard is มยผ. 4502-51.

Good info. Here's a link to the reference standard (I think) but it's in Thai and google translate can't deal with the particular format used at the link. Any idea if there is an English version (official or unofficial) anywhere on the web?

Yes. That's the right link. I've never seen an English version.

[Pib]

The actual requirement is 60 cm for direct burial cable and 45 cm for cable in most types of conduit. It can be reduced to 15 cm if rigid steel conduit is used.

The reference standard is มยผ. 4502-51.

Good info. Here's a link to the reference standard (I think) but it's in Thai and google translate can't deal with the particular format used at the link. Any idea if there is an English version (official or unofficial) anywhere on the web?

Yes. That's the right link. I've never seen an English version.

Thanks....one can hope. I see on Page 13, table 4.3.1 is where the info is you gave. Thanks again.

[Deke]

The actual requirement is 60 cm for direct burial cable and 45 cm for cable in most types of conduit. It can be reduced to 15 cm if rigid steel conduit is used.

The reference standard is มยผ. 4502-51.

Good info. Here's a link to the reference standard (I think) but it's in Thai and google translate can't deal with the particular format used at the link. Any idea if there is an English version (official or unofficial) anywhere on the web?

Yes. That's the right link. I've never seen an English version.

Thanks....one can hope. I see on Page 13, table 4.3.1 is where the info is you gave. Thanks again.

That's the one. The reality though, is that nobody seems to be too concerned about residential installations.

[Pib]

That's the one. The reality though, is that nobody seems to be too concerned about residential installations.

Yea, probably another case of lax regulations enforcement. Kinda like enforcement of the motorcycle helmet law...sometimes the police enforce it; sometimes times they don't. Just yesterday I watched numerous motorcycle drivers pass through a police checkpoint with no helmets...the police would just let them go by because it appeared this checkpoint was only interested in checking trucks...not for emissions but for cargo and paperwork. It must have been truck ticket writing day; not motorcycle ticket writing day.

[cdmtdm]

the real worry is, these guys also do the final connection to the meter with no inspection from the authorities ... these sorts of incidents do highlight how Thailand is still a developing democracy . i wonder what the death rate per year is from electrocution in LOS?

[kannot]

They just did my house, beside the concrete drive, cables are about 1" under the soil, water too.

Thats because they are lazy.

[canopy]

I have experience laying cables underground here. A couple other details: use NYY cable underground. Put sand all around the cable. On slopes it is good to go deeper than 60cm.

Last tip. Warning tape is ineffective in Thailand because anyone digging there will just think it is some buried trash and keep going. I recommend laying empty pvc pipe with the warning tape so when someone hits pipe and breaks it, it gives the best chance they will stop and ask questions.

[seedy]

In Canada, for Teck cable, one meter depth is required.

[cdmtdm]

ok , so i get the electrician back and tell him we must resolve this mains depth ... to me this following comment sums up thai logic ... he said, we put it a little bit in the ground so that when its broken we can dig it up easy .... i walked away and dried my eyes for 10 mins <deleted> !!! so i then returned with a straight face and replied , lets leave it at 20cm but now u put 10cm of cement on top ok ? he thought about it for a minute and said ok , then his merry band of slaves mixed up the mud and in an hour were gone ..go figure !!! some times i just dont get this place ....

[Pib]

In Thailand safety takes a seat in the back of the bus (with no seat beat) in comparison to low installation cost/required manhours which gets a seat in the front (but still no seat belt). I'm surprised they didn't suggest putting a couple buckets of silicone around the mains conduit as they seem to try to fix everything else by smearing some silicone on it.

[thaibeachlovers]

Yeah ^^^, 50-60 cm would meet most regulations globally so would be fine here and would keep it out of the way of normal gardening activities.

You could get away with 30-40cm if under your driveway or path.

Place some lean mix concrete (just sand and cement) on top of the tube before backfilling.

Make sure you use cable rated for damp locations even if you run in conduit, this is the stuff you need http://www.bangkokcable.com/catalog/BCC_CATALOG/NYY2EN.HTML

Wow Crossy, I'm glad I didn't know that back in the home country when I put in an underground cable. Cost me a bundle for 50 meters of standard 6mm cable In some black alkathene water pipe. Been there for over 12 years now.

I'd hate to think what the special stuff would have cost me.

The only thing I do regret though, is that I hadn't gone to 8 or 10 mm due to the voltage drop when using a big electric saw. For normal use, it's fine.

[Crossy]

I've done that too TBL, on circuits protected by earth leakage and over-current devices. Never had an issue.

Our OP however, is talking about his incoming supply which will have no earth leakage protection and no over-current apart from the 25kV village breaker.

Having seen what can happen when the damp gets in to such an installation the correct materials are essential.

[regknick]

Sincerest apology for the multi-quote but several of you seemed to have some solid first hand experience with underground cabling so here goes. Any help would be greatly appreciated.

I'm wondering if there is a Double Insulated (PVC/PVC) Aluminium 25mm or 16mm Sq cable that's capable/acceptable/compliant to bury underground without using Yellow PVC...

and/or

Is Double Insulated (PVC/PVC) Copper the only thing allowed in the ground without Yellow PVC?

Last but not least

If anybody knows where I can get my hands on 6-8 of these little gems, I'd love to hear from you. ;-) They don't have to be this big or carry all the fabulous TOT branding but...

The actual requirement is 60 cm for direct burial cable and 45 cm for cable in most types of conduit. It can be reduced to 15 cm if rigid steel conduit is used.

The reference standard is มยผ. 4502-51.

I have experience laying cables underground here. A couple other details: use NYY cable underground. Put sand all around the cable. On slopes it is good to go deeper than 60cm.

Last tip. Warning tape is ineffective in Thailand because anyone digging there will just think it is some buried trash and keep going. I recommend laying empty pvc pipe with the warning tape so when someone hits pipe and breaks it, it gives the best chance they will stop and ask questions.

I've done that too TBL, on circuits protected by earth leakage and over-current devices. Never had an issue.

Our OP however, is talking about his incoming supply which will have no earth leakage protection and no over-current apart from the 25kV village breaker.

Having seen what can happen when the damp gets in to such an installation the correct materials are essential.

[Langsuan Man]

Depth depends upon where the cable is going to be laid. In my case the cable came under the concrete street, which required cutting the cement, laying the cable and then extending it to the house under the driveway and then into the house. Since the yard had not been filled yet, what the exact depth was is unknown, other than it is now deeper than when originally installed

[regknick]

thanks for the thought... it's a bit different on my site.

thankfully there is govt water and power at the boundary. however, inside the boundary it is freshly cleared and trenched and waiting for installation.

we've calculated load and voltage drop at this point for it but we haven't been able to get a confirmation one way or the other for the code or spec on the burying the cable.

to be safe on depth, the trench is for the most part a full 100cm. i guess what i'm hoping to find out is whether or not there is even a double insulated aluminium cable to bury without needing extra conduit.

or, is copper the only double insulated cable to bury without needing the extra conduit? i do understand and appreciate the notion that with conduit we could easily pull more cable if needed.

however, i'm running close to 2000 meters of cable and the added cost and time on the conduit is not a laughing matter. any thoughts would be greatly appreciated.

[Crossy]

I'm pretty sure PEA and MEA won't permit aluminium cable underground, so you won't find double insulated Al.

[regknick]

Many thanks, Crossy. Although more costly and time consuming I appreciate the insight. For clarity sake, in reading your earlier post about moisture and correct materials...

Is the Yellow Electrical PVC worthy of the task or am I better off using the mondo black and red striped coils of hell I see at Thai Watsadu to put the Cable underground?

I realise I'm asking somewhat ridiculous questions but from what I'm taking away from the info exchange is that I've got a few options to choose from.

a) NYY Double Insulated in the ground without conduit

AL single insulated in the ground with yellow conduit

c) AL or Copper in the ground with the black and red striped conduit

I swear I'm not trying to make this seem as simple as it is but I'm trying to weigh out the pros/cons versus costs and looking for feedback.

[Crossy]

It's important to understand that any underground conduit, ducting or whatever, is there purely to provide mechanical protection and make it easier to replace a cable. These installations always fill with water so a waterproof (double insulated) cable is always required.

Single insulated just won't cut it, it certainly will not get past an MEA/PEA inspection.

If you don't need an inspection because you already have a permanent supply then it's UP2U, but don't come crying on here when you have flames shooting out of both ends of the conduit and no means of cutting the power.

On your own property, with control of the supply end, you can pretty well do as you like, but, as previously noted, there is a LOT of energy in the power supply system, even if on a 'small' village transformer, don't mess with it.

You could protect your underground run with a 100mA RCD at the supply end, MEA/PEA may even let you put it on their pole. But what's the next step when it won't stay connected because your duct is full of water.

[T_Dog]

They just did my house, beside the concrete drive, cables are about 1" under the soil, water too.

One inch down ain't much....but I guess it makes reaching the lines easier/quicker in case of needed repair. But I sure hope the next fellow in your house knows that in case he ever needs to dig there, drive something into concrete an inch or so, etc.

One inch of burial puts your gardener at high risk. Just a bit of erosion and the cable will be exposed, but even if it is still covered, those solid weed wacker blades could pierce through to the live conductors. NYY cable is tough, but not that tough.

[regknick]

wonderful feedback and very much appreciated.

[regknick]

It's important to understand that any underground conduit, ducting or whatever, is there purely to provide mechanical protection and make it easier to replace a cable. These installations always fill with water so a waterproof (double insulated) cable is always required.

Single insulated just won't cut it, it certainly will not get past an MEA/PEA inspection.

If you don't need an inspection because you already have a permanent supply then it's UP2U, but don't come crying on here when you have flames shooting out of both ends of the conduit and no means of cutting the power.

On your own property, with control of the supply end, you can pretty well do as you like, but, as previously noted, there is a LOT of energy in the power supply system, even if on a 'small' village transformer, don't mess with it.

You could protect your underground run with a 100mA RCD at the supply end, MEA/PEA may even let you put it on their pole. But what's the next step when it won't stay connected because your duct is full of water.

Crossy... one more dent for my thick head please.

Yellow Conduit or the Mondo Black and Red Striped Conduit

I will of course seal both.

[Crossy]

Black with a red trace is normal for underground power, if you can keep it in one piece it stands a chance of remaining dry.

[regknick]

Black with a red trace is normal for underground power, if you can keep it in one piece it stands a chance of remaining dry.

1 piece is the trick for sure... there is close to 500 meters is needed so it's going to be a challenge sure.

From what I can see Thai Watsadu has 50 meter rolls. If I can get my hands on 100 meter rolls chances of it staying dry are much better. =)