Underground Electric

[tattoodrob]

I want info please on putting underground cable to a new house,is there a specific pipe that it should go in and what size is it and anyone know rough price?

A builder (Thai) seems to want to put 2 pipes in but i thought was just one biggish black one and run all through that..also i would want to put internet underground too so what pipe this cable would need ?? possibly fiber optic as that is available near the house.

Is there a special electric cable to use underground or just normal supply line same as if was overground?....length underground will be aprox 80 meters.

[Crossy]

Usually the underground stuff is run in black PE tube with a red stripe (for electricity), readily available as farmers use it for irrigation water supply. It needs to be 3 times the diameter of the cable you're putting in it.

 

You can't use just any old cable underground, even in conduit. The correct stuff is NYY 

http://www.thaiyazaki-electricwire.co.th/product.php?id=&view=search&search=nyy

 

Note: NYY can be buried direct without a tube. But it needs to be deep enough to be out of range of gardening activities and (of course) is much more difficult to replace if it does get damaged.

[tattoodrob]

so if i use NYY then could put in any  tube really?  if using the black pipe then im surprised cant use normal cable as the pipe is protecting it from elements etc

[Crossy]

Any underground tube WILL fill with water, no ifs buts or what ifs.

 

The regular cable used for aerial supplies will fail within a few months if it's immersed in water.

 

That failure will be spectacular and likely explosive.

 

You may find parts of your meter afterwards.

 

Yes, you could use pretty well any tube provided it's big enough, the black PE is the lowest cost option.

 

 

[carlyai]

Any underground tube WILL fill with water, no ifs buts or what ifs.
 
The regular cable used for aerial supplies will fail within a few months if it's immersed in water.
 
That failure will be spectacular and likely explosive.
 
You may find parts of your meter afterwards.
 
Yes, you could use pretty well any tube provided it's big enough, the black PE is the lowest cost option.
 
 

I wish you wouldn't keep reminding me about using the wrong underground cable. Now it's all covered in cement and tiles.

Sent from my SM-J700F using Tapatalk

[kamalabob2]

The PEA can be quite strict, for  real reason, about using NYY only underground.  The HDPE red stripe conduit for electrical cable is not the same as farmer irrigation PE black pipe. Getting the correct connectors is not hard at good electrical shops.   I ran Fiber Internet cable to my village house underground in black blue stripe HDPE pipe. It was easy to avoid sharp bends.  

 

For electrical service to from your PEA meter to your in house main breaker panel the NYY is single core. You would use a 25 or 35 or 50 mm single core cable. Two of them.  Both can be in same HDPE black red stripe conduit.  Do NOT put fiber in the same run as electric. 

 

I have met four expats in Buriram who listened to relatives or Thai sparkies and they paid the price to pull VCT or THW  incorrect cable from conduit. They then had to step up and buy NYY.  Crossy is not kidding about blown electric meters.  Even gate lights should be NYY in the black conduit of the appropriate sizes. Water will often find it's way into any yellow conduit or white conduit installed outdoors or underground. 

 

The NYY is cut to your length at any electrical shop.  

[cooked]

16 minutes ago, kamalabob2 said:

The PEA can be quite strict, for  real reason, about using NYY only underground.  The HDPE red stripe conduit for electrical cable is not the same as farmer irrigation PE black pipe. Getting the correct connectors is not hard at good electrical shops.   I ran Fiber Internet cable to my village house underground in black blue stripe HDPE pipe. It was easy to avoid sharp bends.  

 

For electrical service to from your PEA meter to your in house main breaker panel the NYY is single core. You would use a 25 or 35 or 50 mm single core cable. Two of them.  Both can be in same HDPE black red stripe conduit.  Do NOT put fiber in the same run as electric. 

 

I have met four expats in Buriram who listened to relatives or Thai sparkies and they paid the price to pull VCT or THW  incorrect cable from conduit. They then had to step up and buy NYY.  Crossy is not kidding about blown electric meters.  Even gate lights should be NYY in the black conduit of the appropriate sizes. Water will often find it's way into any yellow conduit or white conduit installed outdoors or underground. 

 

The NYY is cut to your length at any electrical shop.  

So how much does this conduit cost delivered? I need to replace four slowly rotting and unsightly wooden poles at some point, I believe the price for a 6 metre concrete pole is ฿8000.- plus the fact that I would need a crane to put them in place which is impracticable. About 50 metres?

 

[Led Lolly Yellow Lolly]

The conduit is HDPE indeed and there is a colour code, but I've never been able to establish which country Thailand is following on the conduit colour codes. I just use red for electrics and blue for water. I just stick optical fibre in whatever I have available, sod the colour code. The cost of the conduit is relative to the supplier. I buy kilometres of the stuff, it's negligible to the cost of digging up the ground to replace cable if you can't pull new cable in. Just today I pulled 250 metres of 35mm 4 core NYY into 62 mm conduit, darn nearly broke my back, I should have got the next size up of conduit. I ended up tying the rope to a golf car and hitting the gas to pull the cable in.

[Led Lolly Yellow Lolly]

On 23/03/2018 at 12:52 PM, kamalabob2 said:

Do NOT put fiber in the same run as electric. 

Are you aware of any specific rule that forbids this? As long as the fibre is fully dielectric (and there is no drop wire running with it) I don't see a problem with it. Obviously LAN cable should not be run with electrics - but dielectric fibre, not a problem AFAIK.

[Crossy]

4 hours ago, NilSS said:

Are you aware of any specific rule that forbids this?

I think it the general wisdom of no comms and power in the same containment. Whilst there's likely no hazard keeping the rules simple makes life easy. We would certainly not mix power and fibre on any of our projects.

 

Of course there's always the danger of damaging the fibre when replacing the power cable.

 

The cost of running a small tube in the same hole as the power tube is small and makes life simple for everyone. Don't forget, any fibre in an underground run needs to be specified as suitable for such.