Electric supply

Post by **mike1976** » January 2, 2015, 1:42 pm

Can anyone offer me advice, or point in the direction of an existing thread, on getting a new electric supply.

Requirement is for a supply to a new house built on land behind wifes parents house which already has it own supply. Location is outskirts of village (farm land) about 4-5 km from town.

Seems simple enough but the question is as the house is 200m back from the road what size cable should I be using and where would I be able to buy it in a single length?. Also not knowing much about these things am I going to get a drop over that distance? Have already had a not particularly helpful fellow from the electric company come by who only seemed interested in selling a "private supply" with a very large price tag just to do a survey.

Appreciate any suggestions or experiences...

Post by **TicToc** » January 2, 2015, 9:12 pm

My run is 8 poles long to the nearest PEA power supply,installed by private contractor as PEA didn't want to know.
PEA will not install a meter at my house as i suppose that makes them responsible for the line.
The cost was 40,000 for the poles complete and another 40,000 for the cable and installation to the consumer box,the cable was the heavy black one,sorry can't be more helpful on that point.Power fluctuates a lot as does voltage where i am.
PEA 's fist meter charged double for the first year plus a deposit was required,returned after the year and meter changed for cheaper rate.This was 7 years ago so all may have changed considerably by now.
Hope it helps.
Good Luck.

Post by **mike1976** » January 3, 2015, 2:14 pm

Thanks TicToc

What type of appliances do you find you are able to power concurrently?

Post by JR » January 3, 2015, 2:53 pm

TicToc,
How long is the distance from the connection to your house that you cover with the 8 poles?

Post by **TicToc** » January 3, 2015, 5:16 pm

Standard distance between poles what ever that is,so i have been told.Or 27 large footsteps.
If you turn the oven on while fan running,fan drops speed.Can run kettle and oven just takes longer.
A lot would depend on what your moo baan can deliver i would think,we have been trying to upgrade the transformer for years.

Post by **bluejets** » January 3, 2015, 10:26 pm

200 metres is a long run and you will experience voltage drop.

How much and whether it will have an effect on the normal operation of your installation depends on what loading you expect to have, the type of conductor used (aluminium or copper) and the sizing of the conductor used as well as the distance run above.

Knowing the loading and the conductor type, this can be calculated to a % Vdrop across the mains run.

If you would like to send a pm I can work it out for you but need the above info as accurately as possible.

I think it would be fairly obvious to you that large consumption devices such as 40 Amp instantaneous bath heaters should be avoided like the plague as they will be the source of your biggest problems.

Post by **mike1976** » January 3, 2015, 11:08 pm

Thanks bluejets....can't pm yet as not enough posts but the details are roughly as follows

Distance will be more or less 200m, decision on conductor type and size still to be decided depending on advice

Water heating will be overnight and stored.... 2 x 3kw heaters but only expect to use one

All lights either <10w LED or some kind of fluorescent

Plan to have electric oven and hot plate but most cooking will be outside on gas

Aircon but don't actually like it too cold so minimal use and individual room units (inverter)

Kettle, washing machine,water pump and other general stuff

Post by **BossHogg69** » January 4, 2015, 7:42 am

I would use 25mm copper

Post by **pf-flyer** » January 4, 2015, 8:24 am

After me and my wife's third trip to the PEA office in Nong Han " without any family members helping " we were fortunate enough to have an PEA engineer that was willing sit down with us and go over our energy needs. My wife and I made a listing of the appliances that we planned to install. I told him that I did a lot of residential house wiring in the U.S. but I was not familiar with the Thai Electrical standards. I told him that my main concern was voltage drop caused by the impedance of a long cable run. We have a 70 meter underground run in conduit to the Pole on the corner of our lot and it runs up that pole and across the road to a PEA pole were our electric meter is mounted. He recommended 25 mm copper and a 35 amp meter for the final installation. We purchased the copper cable and just about all of our electrical supply's at Global House. Our PEA electric meter has two numbers indicating the capacity of the meter. The first number is the calibration current and the second number is the max operating current. We started out with a 15 AMP temp service meter when we were building the house and then PEA installed a 35 AMP meter after the final electrical inspection. The inspection did not take very long. Their only concern was if there was sufficient clearance where our cable crossed over the road so that the sugar cane trucks would be able to go in under the electrical cable crossing the road without catching the electrical cable. We were also very fortunate to have a electrical installer that did a very professional job and did excellent work. He did not take any short cuts. We installed a third safety wire ground system with outside grounding rods thru out the house. All in the internal house wiring in enclosed in conduit in the walls and in wire armor in the attic. My sister in-law found out the hard way that the mice like to chew on exposed electrical wire insulation. Good luck on your project.

Post by **rjj04** » January 4, 2015, 9:22 am

THe PEA man showed us 5A or 15A meter. I believe the 15 Amp meter actually can supply up to 45A without problem.

Aluminum wire is 61% as conductive as copper but it costs only 35% as much (on an equal conductivity basis)
400m of only 16sqmm (you will need at least 24sqmm) will run you around 16,000 THB for copper, and only around 5000 THB for aluminum. Saving around 11,000 THB. For 24sqmm you are talking about saving 17,000 THB by going with Aluminum wire.

This website will allow you to choose a wire size...
http://www.electricaltechnology.org/201 ... lator.html
Although playing around with that website I see it doesn't like off AWG numbers for some reason

You can convert from AWG to square mm with this chart...
http://www.engineeringtoolbox.com/awg-w ... d_731.html

If you stick 45A in the calcuator (max that your 15/45 meter can handle), and choose a 5% voltage drop, it gives you AWG #2 Copper, which is 33.6sqmm. That is pretty close to the 50sqmm Aluminum wire that they sell at Global. If I were you I would choose Aluminum wire, and use a bit of the substantial savings to oversize to 50sqmm so you will never see any problems.

Post by **BossHogg69** » January 4, 2015, 9:32 am

Do not use aluminium cable it is crap and may be cheap but will corrode in the terminals and give problems in the future, copper is far superior.

Post by **rjj04** » January 4, 2015, 10:32 am

Most people here are using Aluminum wire now. If you are worried about corrosion at the terminal connections then you can put some Denso paste (I think that is what is is called), or hot glue or something to seal around the terminals. If I go out and look at my meter's terminal connections in 5-10 years and see they are corroding I'll take the wires out cut new ends (leave some slack in your wire of course), use a wire brush and clean up the terminal. I don't know what type of metal is used at the terminals in the meter but I have not heard of people having problems with corrossion. It would seem that most of these issues have been taken care of back in the 60's and 70's.
https://en.wikipedia.org/wiki/Aluminum_wire

Ask your PEA man if you are worried about corrossion with Al wire at the terminals! I believe that most electrical feeds from utility companies to the main CB panel in US homes are now done with Aluminum wire!! Even the wire runs from the CB box to the larger (split phase 240V) appliances are Al wire now.

Post by **BossHogg69** » January 4, 2015, 10:51 am

Aluminium is used because it is cheap!!!! do not use, I would not use america as a recommendation as their systems are very dated. look at their totally crap plugs and sockets!!! I would use nothing but copper, but as they say up to you, also aluminium is less likely to be stolen, as it is crap, copper is the only way to go for a good installation.

Post by **bluejets** » January 5, 2015, 7:08 am

Nothing wrong with using aluminium conductors just so long as a few basic rules are adhered to.

One being that the correct size is used as ( someone mentioned above) it is not as conductive as copper and therefore requires a larger size to be used for a given loading.

The other and just as important is the use of a paste or compound on the main joints.
(compression fitting please, not twist and tape)

As you will be using a conductor size that will more than likely have no hope of fitting into standard size terminal tunnels at each end of your mains run, it is quite feasable to reduce the conductor size/ type down to a more managable size for the last 0.5metre or so.
( say 16mm /copper)
It is normal practice to do this at both ends of the run.

With your loading for calculations, general light and power use can generally be an educated guess and be fairly close to actual.

Air conditioners these days are usually inverter type with a constant run compressor ramping up and down in speed as demand/heat load changes. They have a particularly desirable property being they do not draw large chunks of power at startup as the old systems from 15 or so years ago.

Calculation for these still must be included but the effect on voltage drop and therefore your main size is less dramatic.

3kw storage heater used in an "off-peak" arrangement is a good move. I would even look at the possibility of solar.

If at all possible, steer towards gas for you oven/cooker but up to you as you will have to add quite an amount to the mains size to offset for this with electric.

Oh, and also (probably just as important) if you use aluminium and you leave your house for a few days, chances are you will still have power connected when you return. Copper conductors have an additional magnet/ inductive effect other than those it was manufactured with that some find irrestable. (as scrap metal)

Post by **rjj04** » January 5, 2015, 8:58 am

So bluejets, do you think that the terminals in the meter itself would have any galvanic corrossion problem when connected to Aluminum wire? What metal type is used for the terminals in these meters?

Post by **Khun Paul** » January 5, 2015, 9:49 am

when i recently had a few problemns with my supply ( the meter was buggered, the feed wire was aluminium ), the local PEA chaps came out , replaced the meter, and changed the feed wires to high quality copper, now why in hell did they do that if aluminum is so good, the simple answer as I understood it, was that Aluminum wire does over the years deteriorate and thereby can and in my case did cause problems . While it is considerably cheaper ( that is why most Thais use it ) in the long run it can be more expensive, so the extra cost is far outweighed by the security of good installation . Electiricty like Gas, installations and fittings should never be the cheapest but the best, for reasons as stated above, safety/security and last of all peace of mind.

Oh by the way many Thais will use Aluminium but charge you for Copper, so beware, buy the wire yourself and get them to install it.

Post by **BossHogg69** » January 5, 2015, 10:04 am

This is exactly why I say aluminium is crap, it always corrodes despite any measures to prevent it, and never join aluminium to copper it will corrode very badly due to a chemical reaction, never do it, just do it correct once and use copper all the way.

Post by **bluejets** » January 6, 2015, 8:40 am

rjj04 wrote:So bluejets, do you think that the terminals in the meter itself would have any galvanic corrossion problem when connected to Aluminum wire? What metal type is used for the terminals in these meters?

Meter tunnels are mostly plated brass.
These are usually sized to a maximum capacity of around 16 to 25square mm cable
(cross section area not square shape..

)
The reason is most instances with installations over 100Amp, CT metering is used.

If, as in the case with many installations in Thailand, large mains are required to overcome voltage drop, sizes of 25 square mm and upwards are common and obviously will not fit the meter tunnels (or your main switch at the house end) so therefore the use of the smaller copper tails.

I suspect that anyone who has used aluminium before and has had corrosion problems would not have used any jointing paste designed for these connections.

In the ideal world, far from Thailand, there are, and we use without any problems, bi-metal lugs and links for connection between the copper and aluminium medium, however, in the case above where you need a reduction in cable sizing, there is no product available as far as I know.

Usual practice in this case is to use a copper link and the process is to select a link that firmly or near-as, fits over a full link length of both the large size aluminium and the small size copper cable. Both are given a good coating of oxidization paste and laid out overlapping inside the link. This is then crimped and covered with a high grade heatshrink such as Rachem. The best to use here is the type with internally applied "glue" which secretes out of the joint upon proper application as a verification of the application. It remains semi-flexible and has a high voltage rating enough for domestic and commercial systems.

Using the copper link is not the absolute best solution overall but it is the best you will get in Thailand.
Other than that, get hold of some bi-metal lugs for the aluminium and some copper lugs for the tails, and bolt them together. Makes for a rather large and cumbersome joint, especially when trying to fit any heatshrink insulation, but I have done it before. ( and don't forget the jointing paste....

)

If you can afford the copper and think it will still be there if you take a few days away from home , then by all means go that way.

Post by **bluejets** » January 6, 2015, 8:54 am

Now for those that like to poo-poo aluminium, yes it is cheaper and in a country like Australia, where the electrical standards are some of the highest in the world, it is probably why supply authorities have been using it for many years now. Having said that, by the use of proper jointing systems, very few problems occur.

Post by **BossHogg69** » January 6, 2015, 9:07 am

None of you guys talking about aluminium have in my mind no experience in the problems for the future, I worked for many years in the highway electrical industry and aluminium was a NO NO due to the long term problems associated with this crap stuff, any one who uses it does so on a cost saving basis only and screw the future problems as someone else will be paying for it, use it if you want, but I will enjoy saying, TOLD YOU SO!!!!!!