Underground cable for new house

[tukpong]

Hi all,

 

Building a new house and the electrician has quoted to run underground cabling for house supply.

1) He has said the cable has to run to the house then back from the house to the meter ??? that is 2 x cable runs (10,000 baht x 2 ), can anyone explain what he means ?

2) Run is about 80 meters he says there is not a lot of difference in cost between underground and overhead for this distance ( supply and install of concrete poles etc ).

3) Who installs internet / fibre cable ? Electrician or internet provider ? Can it be run in the same trench but separate conduit from electrical?

 

 Cheers, any comments greatly appreciated.

 

 

 

[Anythingleft?]

Live wire in and neutral return, you cannot only have 1 wire if that is what you are suggesting
The internet etc will be run by the company of your choice, however you can pre-lay cables for them to use as they will always take the easiest route which may not be desirable for you....

Sent from my SM-N950F using Tapatalk

[Crossy]

Hmmm.

 

Underground should be rather more expensive than poles, longer job digging the trench, more expensive cable (check he does use the correct cable). Get him to quote for both methods.

 

Whilst the trench is open drop in a run of 1¹/₄"  HDPE tube for the internet chaps to run their cable / fibre, keep it 6" or so away from the power cable (which should be in its own tube in case you need to replace it).

 

[sometimewoodworker]

1 hour ago, Crossy said:

Whilst the trench is open drop in a run of 1¹/₄"  HDPE tube for the internet chaps to run their cable / fibre, 

I would also put in to the HDPE (before putting it in the trench) a length of 12mm, 8mm, or minimum 6mm polypropylene rope for the internet people to use to pull thier cable with. If you don't then do not be surprised when they refuse to put the fibre underground. Fishing a 85 metre run of small diameter pipe is not the easiest thing to do.

[Esso49]

1 hour ago, Crossy said:

Hmmm.

 

Underground should be rather more expensive than poles, longer job digging the trench, more expensive cable (check he does use the correct cable). Get him to quote for both methods.

 

Whilst the trench is open drop in a run of 1¹/₄"  HDPE tube for the internet chaps to run their cable / fibre, keep it 6" or so away from the power cable (which should be in its own tube in case you need to replace it).

 

Crossy,

 

Although more expensive wouldn't galvanised steel pipe, with screwed couplings  be better for future internet cables etc as it would provide for more shielding and obviously more physical protection/and or resilience to subsidence ?

[Wirejerker]

Drop in a couple extra tubes and bury the ends at your fence line to be recovered later for electric gate, security camera and lights etc


Sent from my iPad using Tapatalk

[sometimewoodworker]

52 minutes ago, Esso49 said:

Crossy,

 

Although more expensive wouldn't galvanised steel pipe, with screwed couplings  be better for future internet cables etc as it would provide for more shielding and obviously more physical protection/and or resilience to subsidence ?

If you are going to run in air then metal pipe with clamped couplings works, and allows water to drain if it gets in.

 

underground always use plastic as metal will fill with water and rust through really quickly.

[Crossy]

20 minutes ago, Arjen said:

What if you use Stainless Steel?

$$$

 

There's no need for extra shielding and such like and HDPE is strong and cheap ?

 

[bankruatsteve]

Most (?) new connections are being done with fiber optic and doesn't need any shield.

[sometimewoodworker]

5 hours ago, bankruatsteve said:

Most (?) new connections are being done with fiber optic and doesn't need any shield.

If it's under the lawn/drive then a shield helps protect from mechanical damage.

[Wirejerker]

What’s the depth cables are buried in the LOS. As a comparison in Aus under traffic areas it’s 750mm


Sent from my iPad using Tapatalk

[sometimewoodworker]

1 hour ago, Wirejerker said:

What’s the depth cables are buried in the LOS. As a comparison in Aus under traffic areas it’s 750mm


Sent from my iPad using Tapatalk

As little as they can? or as deep as you insist.

[Crossy]

12 hours ago, Wirejerker said:

What’s the depth cables are buried in the LOS. As a comparison in Aus under traffic areas it’s 750mm

 

In the UK there's no absolute, BS 7671-2008 regulation 522.8.10 is the guide to take. The last sentence is 

"Buried cables, conduits, and ducts shall be at a sufficient depth to avoid being damaged by any reasonably foreseeable disturbance of the ground" 

A rule of thumb is in a garden below one and half spade length or below 500mm and under drives and such between 500-750 mm.

[kamalabob2]

The OP should heed the advise of previous posts on the separate HDPE conduit to separate his two electric cables in one HDPE cable and his CCTV and fiber optic cable in a different HDPE conduit.  The PEA has written guidelines on what size cable for under ground and in the air or along a fence. The PEA will only allow NYY one core for underground.  PERIOD.   THW is not allowed underground.  The price of a quality brand of NYY 1 by 16 or 1 by 25  or 1 by 35 or 1 by 50 is determined by meter size and LENGTH of the run to your load center. BCC | Yazaki | Phelps Dodge are recognized at top grade brands of electric cable in Thailand. The PEA has this on line and in their offices. They have several posters and brochures at the Buriram PEA office on Highway 2074. Any builders merchants store or electric shop can order NYY in the size the OP needs to the length he needs.  If a local contractor did the measurements you might had two meters to your length.  

For 80 meters from the PEA 15/45 electric meter on a pole to his load center with circuit breakers in his home the minimum NYY copper cable to run underground in HDPE conduit is 1 core by 35mm.  It is listed on the 2nd chart provided by the Buriram PEA electric office.  It is a one time investment. Too small of a cable size will lead to voltage drop, and trouble with air conditioners, water pumps and light bulbs.  

Edited September 7, 2018 by kamalabob2

[beddhist]

Hi folks,

 

I found this topic just in time, as our builder wanted to go and buy standard cable to bury. He had never heard of NYY. (In town, mai mee, so an extra 160 km round trip to buy it).

 

On 9/1/2018 at 6:20 AM, Crossy said:

Whilst the trench is open drop in a run of 1¹/₄"  HDPE tube for the internet chaps to run their cable / fibre, keep it 6" or so away from the power cable (which should be in its own tube in case you need to replace it).

 

Excellent idea, but would this 2nd run at 15 cm above the power cable not be a little close to the surface?

 

Any idea where we can hire a Ditch Witch? I guess they are unknown here?

 

The builder wants to use PVC ducting. According to him, PE is not strong enough when the ground turns to slush in the wet season (I don't believe that, it withstands NZ winters with cows trampling on it.) and the joiners are made of steel and so rust away. (D we need joiners? How do we get a cable into a 30 m long duct? How do you get a draw string in?)

 

I think he wants to cut it into sections and then re-join them.

 

Sorry about so many questions at once. I think I will come up with a few more...

 

Thanks!

Peter.

[Crossy]

Nobody said put the fibre conduit 15 cm above the power, but in reality if the power is deep enough then even on top the fibre will be fine.

 

You (or your contractor) should be able to get a mini-digger with a narrow (trenching) bucket. I'm sure that trenchers similar to the Ditch Witch do exist. I've not seen one, but then again, I've not been looking. Maybe your local PEA or MEA office can assist.

 

MEA and PEA use PE conduit, good enough for them, good enough for you. 

 

To get the drawstring in use a long snake or a light line (fishing trace) with a rag wad on the end and blow it through with compressed air.

 

Avoid cutting and you won't need joiners (mostly), use PE joiners on PE pipe (get them from the place you get the pipe). 

[bankruatsteve]

10 minutes ago, beddhist said:

Excellent idea, but would this 2nd run at 15 cm above the power cable not be a little close to the surface?

 

If the internet is using fiber optic cable - which it likely would be these days, there is no need to put space from the electric.

[beddhist]

Thanks, I will have a word with the builder. Maybe go to the source and see what they have.

[sometimewoodworker]

16 hours ago, bankruatsteve said:

If the internet is using fiber optic cable - which it likely would be these days, there is no need to put space from the electric.

You don't need space from the power cable, but you do need it to be in its own separate conduit.

 

16 hours ago, beddhist said:

The builder wants to use PVC ducting. According to him, PE is not strong enough when the ground turns to slush in the wet season (I don't believe that, it withstands NZ winters with cows trampling on it.) and the joiners are made of steel and so rust away. (D we need joiners? How do we get a cable into a 30 m long duct? How do you get a draw string in?)

 

I think he wants to cut it into sections and then re-join them.

He has never used the LDPE pipe so doesn't want to do it the correct way. Do not allow any joins in the pipe, the standard roll is 100 metres long, if there are any joints underground it will fill up with water.

 

our cable is in a 70 metre pipe so it's not too difficult. Do get pipe that is quite a bit bigger than th cable you are putting in it or you won't be able to get the cable in. Do put the power cable in before putting it in the ground. Do make sure you put a polypropylene guide rope into the pipe for the internet fibre line and leave plenty of spare pipe and line at each end.

 

FWIW the LDPE is a lot cheaper than PVC.

[taninthai]

That nyy cable is about 90 bht a meter cant remember if that is 10 mm2 or 16 mm2 that is for 2 core ,something don’t sound right with your pricing .is this running on your own land ,so you only need one cable that has 2 inner cores ,maybe your electrician is using the same cable that they use for over head lines there for running two actual cables,,,,,this is not the way to do it underground.

Edited November 22, 2018 by taninthai

[Fruit Trader]

4 hours ago, sometimewoodworker said:

FWIW the LDPE is a lot cheaper than PVC.

HDPE is preferred.

 

Eg - http://www.thaipipe.co.th/product-03-eng.html

[beddhist]

According to kamalabob2's post #15 it has to be single core. IIRC we paid 76B/m for 2.5 mm² aluminium. Amazingly, the day after we asked for the connection it was already done!

[sometimewoodworker]

2 hours ago, Fruit Trader said:

HDPE is preferred.

 

Eg - http://www.thaipipe.co.th/product-03-eng.html

It may well be preferred, it may well be better. The difficulty is that it isn't what is in stock in every one of the usual suppliers. So given the choice of LDPE now and which size and how many hundreds I'd metre tools do you want or HDPE maybe can be ordered or just "no have" you may be able to guess my choice.

[janclaes47]

Why would a higher pressure rated tube make any difference for an electrical cable conduit?

[Fruit Trader]

2 hours ago, sometimewoodworker said:

It may well be preferred, it may well be better. The difficulty is that it isn't what is in stock in every one of the usual suppliers. So given the choice of LDPE now and which size and how many hundreds I'd metre tools do you want or HDPE maybe can be ordered or just "no have" you may be able to guess my choice.

Electrical wholesalers in my area (Chon Buri) only stock HDPE pipe. The local PE pipe shop stocks LDPE irrigation pipe but all of their electrical pipes with the red stripe are HDPE and most of the water pipe with blue stripe is HDPE with several grades available. Its much the same story around our farm in Chanthaburi.

 

I guess out in the jungle anything goes and you grab whats available. 

[Fruit Trader]

2 hours ago, janclaes47 said:

Why would a higher pressure rated tube make any difference for an electrical cable conduit?

Which post mentions pressure so we can all play along?

[Patriot1066]

On 8/31/2018 at 2:59 PM, Anythingleft? said:

Live wire in and neutral return, you cannot only have 1 wire if that is what you are suggesting
The internet etc will be run by the company of your choice, however you can pre-lay cables for them to use as they will always take the easiest route which may not be desirable for you....

Sent from my SM-N950F using Tapatalk
 

We always specify underground from the pole to the houses we build. But make sure  they run them deep enough as one of hours was severed and it was three phase so big issue.

 

I started putting dat in underground but it was copper pairs so as its now fibre it just gets run in as normal above. Technology moved too fast to use the copper pairs.

 

 

 

 

[janclaes47]

3 minutes ago, Fruit Trader said:

Which post mentions pressure so we can all play along?

Your post

 

5 hours ago, Fruit Trader said:

HDPE is preferred.

 The opnly difference between Hdpe and Ldpe is the pressure rating

[Fruit Trader]

3 minutes ago, janclaes47 said:

Your post

 

 The opnly difference between Hdpe and Ldpe is the pressure rating

 

3 minutes ago, janclaes47 said:

Your post

 

 The opnly difference between Hdpe and Ldpe is the pressure rating

Which post mentions pressure so we can all play along?

[janclaes47]

5 minutes ago, Fruit Trader said:

 

Which post mentions pressure so we can all play along?

 

 

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

Edited November 22, 2018 by janclaes47