5 hours ago, beddhist said:

According to kamalabob2's post #15 it has to be single core.

I'm scratching my head about that. I generally use singles cores underground anyway because it's cheaper and easier to handle, but I really don't see any reason not to use multicore, and I see it deployed regularly even on PEA installs. If there is such a rule I'd be interested to read about it.

1 minute ago, janclaes47 said:

 

 

Since the only difference between HDPE and LDPE is the strength your argument for recommending it would be the strength. AKA pressure rating.

 

Tell us why HDPE is recommended

 

LDPE is softer, more flexible and melts at a lower temperature than HDPE HDPE is harder has a higher chemical resistance and can withstand higher temperatures.

 

And the polymer chains bla bla bla

Just now, Fruit Trader said:

 

LDPE is softer, more flexible and melts at a lower temperature than HDPE HDPE is harder has a higher chemical resistance and can withstand higher temperatures.

 

And the polymer chains bla bla bla

And which of those values would be beneficial for underground electrical wires.

 

Hmm, let me guess. The polymer chains determine the tensile strength ( aka pressure rating) there is no fire underground, and most likely also no chemical exposure, so only the flexibility would make it easier to lay cables underground.

 

Hey wait, that mean LDPE would be recommended.

 

 

 

Just now, janclaes47 said:

And which of those values would be beneficial for underground electrical wires.

 

Hmm, let me guess. The polymer chains determine the tensile strength ( aka pressure rating) there is no fire underground, and most likely also no chemical exposure, so only the flexibility would make it easier to lay cables underground.

 

Hey wait, that mean LDPE would be recommended.

 

 

 

I have answered already. If you have some difficulties with English maybe limit your posting scope.

3 minutes ago, janclaes47 said:

flexibility would make it easier to lay cables underground.

 

Hey wait, that mean LDPE would be recommended.

 

 

 

Pfft, have you ever tried pulling 16mm cable through a pipe with bends in it? Flexibility my @rse.

1 minute ago, Fruit Trader said:

I have answered already. If you have some difficulties with English maybe limit your posting scope.

Thanks for enlightening me, fruit trader the almighty

Just now, NilSS said:

Pfft, have you ever tried pulling 16mm cable through a pipe with bends in it? Flexibility my @rse.

 

Yes I pulled 32 meters through it

20 minutes ago, NilSS said:

I'm scratching my head about that. I generally use singles cores underground anyway because it's cheaper and easier to handle, but I really don't see any reason not to use multicore, and I see it deployed regularly even on PEA installs. If there is such a rule I'd be interested to read about it.

I've seen this stated before, but can't find anything in writing.

 

I suggest a word with your local PEA office before buying any cable.

Toot late, I took his word for it. I assumed the document in Thai posted at the beginning stated that, but I can't read Thai.

1 hour ago, janclaes47 said:

 

 

Since the only difference between HDPE and LDPE is the tensile strength your argument for recommending it would be the tensile strength. AKA pressure rating.

 

Tell us why HDPE is recommended

Won’t you encase it in concrete to protect from damage and rats?

46 minutes ago, Crossy said:

I've seen this stated before, but can't find anything in writing.

You might be referring to the line below the cable size table which is written in the usual Thai style. I have translated to show how this remark could be confusing. 

 

Remark - Copper cable must put in PVC pipe using separate cables underground use NYY only.

 

1 hour ago, NilSS said:

Pfft, have you ever tried pulling 16mm cable through a pipe with bends in it? Flexibility my @rse.

Wouldn't it be better to pull the cable 1st before there're bends in it?

1 minute ago, sometimewoodworker said:

Wouldn't it be better to pull the cable 1st before there're bends in it?

It should pull through ok f the ends are smooth and the tube diameter is adequate ?

We just finished putting our power cable underground, our cables were overhead but the power poles were not behaving themselves, the PEA installed them for us, and we put concrete footings around the bases, but our ground becomes so fluid during the rainy season that they began leaning more and more and the cables drooping more and more.

           We contacted the PEA about having them unhook the current cables and hook up the new cables once we were done, and their initial reaction was to question us as to who the electrician was we had doing the job, When our Thai niece told them it was a licensed electrical contractor from America, the fellow she was talking to said "American standards may not be the same as Thai standards".

            So our niece asked hi to send us the Thai standards, to which he replied, "we don't have any specific written standards for that".

       He said they would have to come and inspect our work before committing to changing the cable over.

             We used HDPE and 25 guage NYY cable, as we were unable to source the size of poly we wanted (1-1/4") we used 2 each 1" polys and just ran one cable in each pipe. We dug ditch to 50cm and installed 4 inch metal electrical runner up the side of the house.

             When our niece sent pictures of our work to the PEA fellow and said we were ready for the cables to be changed at the meter, his reply was, "go ahead and do it yourself, I can see that you guys did a lot of work". Swapping the cables out at the meter and service in the house went quickly.

               Our contractor friend from back home said the use of the NYY cables was overkill, as the 'W" in THW stands for "wet", and that's what code calls for in the rainy Pacific North West where we live, according to him NYY is rated for direct burial. Our cable had been up for the 18 years we have been here, so I don't mind that we bought new cable. The old 25 gauge THW is really stiff and we weren't sure the insulation coating wasn't compromised by the weather here.

             It was a lot of work, the ground was rock hard, and finding the correct materials was a pain, but I would do it over again if needed, peace of mind is priceless.

 I do hope you used 25mm² rather than 25AWG 🙂

 

THW is definitely NOT suitable for underground use even in conduit. And you are right, re-using it after exposure to UV and weather would be unwise anyway.

 

 

NYY is the stuff you want, whilst it is rated for direct burial sticking it in conduit give extra mechanical protection.

 

 

What you've got should be good to go 🙂 

 

 

Doers anyone know if there is a maximum distance that cables can be placed underground between the house and the meter? Our distance is about 60m, the house is closer than that but the switchboard is on the opposite side of the house so I wanted to run around the house, in HDPE pipe of course. Using the correct NYY cables of course.

Am I reading this translation correctly that the maximum is 40m for the larger meter that we will need?

 

In order to maintain volt-drop requirements for 60m you will need 50mm² copper***. This may not fit in the meter or your main breaker so a short pigtail of 35mm² will need to be spliced on each end.

 

It shouldn't actually be an issue other than cost** but do talk to your local PEA office to get their opinion.

 

They may suggest going to 3-phase if you really need a 100A single-phase supply. Much actually depends upon the loading of your local transformer.

 

**Do note that the cheaper aluminium cable is not permitted underground for domestic installations.

 

*** 35mm² would be just acceptable if PEA agree.

 

3 hours ago, Crossy said:

In order to maintain volt-drop requirements for 60m you will need 50mm² copper***. This may not fit in the meter or your main breaker so a short pigtail of 35mm² will need to be spliced on each end.

 

It shouldn't actually be an issue other than cost** but do talk to your local PEA office to get their opinion.

 

They may suggest going to 3-phase if you really need a 100A single-phase supply. Much actually depends upon the loading of your local transformer.

 

**Do note that the cheaper aluminium cable is not permitted underground for domestic installations.

 

*** 35mm² would be just acceptable if PEA agree.

 

Thanks mate. Yeah the cost of a 35mm 100m roll is currently around 16k each, so to double up for 60m runs I would need 4 rolls with a ton of wastage on each roll, its starting to get up there in cost to do that...

Might have to think of an alternative...

23 minutes ago, firewight said:

Might have to think of an alternative...

 

Poles with aluminium cable for most of the distance transitioning to copper underground where it shows?

 

We were going to have underground, then the flooding in 2011 happened.

 

Madam decided we were going to go overhead.

 

3 hours ago, Crossy said:

 

Poles with aluminium cable for most of the distance transitioning to copper underground where it shows?

 

We were going to have underground, then the flooding in 2011 happened.

 

Madam decided we were going to go overhead.

 

Could it be something like, underground from the meter to the side of the house (about 25m) and then aluminum cable from there using a junction or something on the side of the house and continue through the roof?

 

I'm struggling with the fact that the distance is OK on poles, but not underground... The following are my current thinking...

Option 1: Underground copper is actually about 55m but I allowed a little more for running in and termination at each end. Follow the red line around the left side

 

OR

 

Possible Option 2: Underground copper to the house about 25m, then aluminum through the roof to the switchboard, about 15-20m.

 

Having poles inside the property would be messy and a shame...

 

Option 3: Overhead aluminum (cheapest) into the house from the pole and then inside the roof to the switchboard is what I am trying to avoid.

 

I am open to any alternate ideas you may have...

 

Current photo of the house just for context.

 

The PEA pole is here.

 

Cheers!

i would consider this option (see the picture below): a short underground cable run ..

 

question: from the pole, running underground through the driveway 5m, has this been legally clarified in writing regarding access rights and ownership?

 

 

6 hours ago, motdaeng said:

i would consider this option (see the picture below): a short underground cable run ..

 

question: from the pole, running underground through the driveway 5m, has this been legally clarified in writing regarding access rights and ownership?

 

 

Thanks for the idea, but its not possible, the switchboard is already on the other side of the house, and the house wiring is already complete...

 

Access from the pole is not an issue.