Electric supply

Post by **glalt** » January 6, 2015, 9:33 am

I once rented a brand new house that had never been lived in. After moving in I discovered that many of the outlets and switches didn't work. I was surprised that the entire house was wired with aluminum wire. I turned off the main breaker and after re-tightening all the connections, everything worked. I'm not a fan of aluminum wire.

That said, the vast majority of Thai houses use the standard 25 sq. mm aluminum wire from the meter to the main breaker box. I would say that as long as there are no aluminum to copper splices that you will have no problems. I had our house re-wired and changed to a 15-45 A meter. My wife's uncle happens to be a very good Thai electrician and he had no qualms about using aluminum from the meter to the new breaker box. I have a Square D breaker box and there is absolutely no sign of corrosion at the lug connections. There are no aluminum wires in the house itself.

Post by **glalt** » January 6, 2015, 9:58 am

A little story;

A good friend of mine built a large house that was going to have a number of large air conditioners. The power pole and his new transformer were across the road from the house. He is quite well off and didn't want any poles on his property. He had the road dug up and buried PVC pipe all the way to the house. He used very heavy copper cable all the way, no aluminum cable for him. The house was not quite finished by that time. The next time he went to the house he found that he had no electricity. After investigating he found that the wire had been cut at the pole and the house. The PVC pipe made pulling about 150 meters of his expensive copper cable quite easy. It was replaced with aluminum. LOL!

Post by **bluejets** » January 6, 2015, 2:19 pm

Bloke down here in Aus tried to knock off some 3.3kv out of a cable pit with a battery powered angle grinder one night about 2 years ago.

Boys in blue found him slumped over hanging out of the pit .
After making sure he was "disconnected" they arrested him.

Very lucky to survive.

Post by **mike1976** » January 7, 2015, 4:44 am

: bi metallic.jpg (1.79 KiB) Viewed 1233 times

Having started this thread in the first place I firstly wanted to say thanks to all the "posters" for the information and debate which has really helped.
Where I got to in my head from what has been said is that copper is the golden bullet but is has drawbacks...price and the fact that it might develop legs..... so as I am looking at nearly 500m in total it is going to be expensive and there is a strong likelihood of developing said legs.

The argument against aluminium seems to be down to the last metre and potential deterioration around connection particularly if stepping down from 50 mm2 aluminium to 25mm2 copper to a) avoid the voltage drop and b) find something that would fit the termination points on the meter and the distribution board.

So someone mentioned bi metallic lugs. As i am in UK at the moment I did a bit of googling and had a couple of really helpful conversations with cable companies here and they pointed me in the direction of this. Likely no more than 500 baht equivalent each but a crimping tool needed also which they are going to send me a price for....

Seems pretty good middle ground to me? Interested in further views

Post by **bluejets** » January 7, 2015, 7:47 am

The bi-metal links or lugs should have jointing paste supplied but you should check.

The crimpers can be a simple displacement type or a more elaborate die type.

Displacement type presses an anvil into the lug to secure the cable. Several crimps can be made to assure connection.
If using this I would still seal with Rachem heatshrink .

Die type (usually hydraulic) compresses the complete link and cable via a 6 sided die into one mass.

First one (for 50 sq mm) would be one hell-of-a-crimper ( I've only seen them that will handle up to 25 sq mm)

Last one you won't get much change out of 1000.00 pounds.

Hire companies usually have them though.(but in Thailand....??)

Post by **Barney** » January 9, 2015, 5:25 pm

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?

Galvanic corrosion may be the wrong term here rjj04.
If you are connecting AL to CU then you may have a couple of problems, but not if you connect the correct way.

Aluminium is a reactive metal more than a corrosive metal, so moisture must be kept from the CU/AL connecting joint. If the connecting terminals in the meter are CU then you must keep them dry. Moisture will cause a reactance in the AL against CU.
Also CU and AL will have a differing temperature co efficiency rate, which means both metals will expand and contract at different rates when they heat up. Problem under load.
If your connection is by cable crimping lugs then the correct AL/CU bi metal lugs can be procured and all problems goes away.
If you have AL to AL no problems, Al will form a light oxide coating which will prevent further corrosion in normal circumstances.