Underground cable for new house

[Led Lolly Yellow Lolly]

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.

[Fruit Trader]

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

[janclaes47]

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.

 

 

 

[Fruit Trader]

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.

[Led Lolly Yellow Lolly]

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.

[janclaes47]

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

[janclaes47]

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

[Crossy]

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.

[beddhist]

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.

[Patriot1066]

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?

[Fruit Trader]

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.

 

[sometimewoodworker]

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?

[Patriot1066]

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 ?

[Lee4Life]

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.

[Crossy]

 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 🙂