Joining Aluminium And Copper Cables?

[kloghead]

I've searched this forum and can't find a relevant answer to my question...

I have 235 meters of 25 mm2 aluminium cable from the meter to my house (under construction). Last night someone stole the the final 20 meters to the consumer unit so I need to join another 20 meters to complete the run. My electrician seems to think splicing 16 mm2 copper cable to the aluminium will be OK but I'm not convinced he's correct.

I always thought joining dissimilar cable is a no-no... What do you sparkies think about this? Also, what type of joining device (sleeve, clamp, etc) should be used? I'm at a standstill right now so any quick answers are greatly appreciated. Thanks

[Darrel]

I think brass connectors are what you need to consider.

http://www.google.co.uk/search?hl=en&q=join+copper+aluminium+cable

[Gary A]

I'd strip about 3 inches of insulation off both the copper and the aluminum cables. Wrap them lengthwise together as tightly as you can and solder them together. Make sure you DON'T use acid core solder. You're right, aluminum wire corrosion is a big problem here in Thailand. Even good quality set screw type clamp connectors can corrode and heat up.

[Crossy]

Soldering Aluminium is difficult enough under controlled conditions, it's not something I'd like to try in the field.

The proper way is to use bi-metal crimps like the ones in this document http://www.cablectrix.co.uk/images/products/klauke-manufacturers/Compression%20cable%20lugs%20and%20connectors%20for%20aluminium-copper%20connections%20%28PAGES%20116-122%29.pdf good luck finding them.

For now I'd bung the cables in a regular screw connector to get the supply on whilst you look for or order the proper beasties.

You could probably find cable lugs rated for Aluminium, put one on the Al cable and a copper one on the copper cable, join with a stainless bolt and wind loads of tape over the lot. QED.

Since the lugs and crimps both need a special tool to apply properly I'd be talking to a sparks who knows what they are and how to apply them. Good luck there too but you may find talking to your local supply distribution chaps useful, they would likely be doing this type of thing fairly regularly.

[kloghead]

Thanks for the replies, amigos. I spent hours on the web yesterday researching this situation and my eyeballs are about to fall out . It seems electrolysis and galvanic corrosion are the bugaboos when joining AL-CU. Applying an oxygen cleaner (Penetrox, Notrox) to the aluminium and then filling the connector with an anti-oxidizing paste--don't know the name of that product, yet--is key to making a connection that will be safe and durable.

Crossy--I'm waiting on a reply from Cablectrix UK about their 'Klauke' connectors so maybe I'll have good news from them soon. Yesterday we made the join much the same as you suggested but wrapped some 3M '23' stretch tape (which I conveniently 'acquired' last time I was offshore) around the join and covered that with plain old elec tape. The sparky says that's the way they do it all the time here--no problems! We shall see...

I'm going to the local PEA office today and ask the manager if he knows anything about the connector I'm after.

Thanks again everyone for your replies

PS Did I spell 'aluminium' correctly? I'm a Yank and we call it 'aluminum'

Edited June 22, 2011 by kloghead

[David006]

Thanks for the replies, amigos. I spent hours on the web yesterday researching this situation and my eyeballs are about to fall out . It seems electrolysis and galvanic corrosion are the bugaboos when joining AL-CU. Applying an oxygen cleaner (Penetrox, Notrox) to the aluminium and then filling the connector with an anti-oxidizing paste--don't know the name of that product, yet--is key to making a connection that will be safe and durable.

Crossy--I'm waiting on a reply from Cablectrix UK about their 'Klauke' connectors so maybe I'll have good news from them soon. Yesterday we made the join much the same as you suggested but wrapped some 3M '23' stretch tape (which I conveniently 'acquired' last time I was offshore) around the join and covered that with plain old elec tape. The sparky says that's the way they do it all the time here--no problems! We shall see...

I'm going to the local PEA office today and ask the manager if he knows anything about the connector I'm after.

Thanks again everyone for your replies

PS Did I spell 'aluminium' correctly? I'm a Yank and we call it 'aluminum'

notice the T joints from overhead to meters are all what look like bronze screw connectors with tape over ...not sure our Thai electrical companies use shrink or self ( stretch)amalgamating tape with gels therein to make a secure waterproof joints...

[katabeachbum]

Thanks for the replies, amigos. I spent hours on the web yesterday researching this situation and my eyeballs are about to fall out . It seems electrolysis and galvanic corrosion are the bugaboos when joining AL-CU. Applying an oxygen cleaner (Penetrox, Notrox) to the aluminium and then filling the connector with an anti-oxidizing paste--don't know the name of that product, yet--is key to making a connection that will be safe and durable.

Crossy--I'm waiting on a reply from Cablectrix UK about their 'Klauke' connectors so maybe I'll have good news from them soon. Yesterday we made the join much the same as you suggested but wrapped some 3M '23' stretch tape (which I conveniently 'acquired' last time I was offshore) around the join and covered that with plain old elec tape. The sparky says that's the way they do it all the time here--no problems! We shall see...

I'm going to the local PEA office today and ask the manager if he knows anything about the connector I'm after.

Thanks again everyone for your replies

PS Did I spell 'aluminium' correctly? I'm a Yank and we call it 'aluminum'

notice the T joints from overhead to meters are all what look like bronze screw connectors with tape over ...not sure our Thai electrical companies use shrink or self ( stretch)amalgamating tape with gels therein to make a secure waterproof joints...

PEA uses bronze screw connector and the tape lasts 6-12 months

when the copper/aluminum joint has corroded, one simply cuts off some cable and join again. To be repeated every 6-12 months

heck even back home underground joints with proper stuff on occasions was broke, and driveway had to be digged up after 10 years or so

often better to use same material all the way

[kloghead]

I wanted to use copper cables for the full run (235 meters from the road) but out here in the sticks the thieves will take it the night after it's installed. I know of 3 homes in my 'hood where this has happened in the past six months. Has anyone priced 16 mm2 copper cable lately?

Anyway, we ended up using the bronze connectors from the PEA--my sparky thinks they're brass. Treated the Al with NOTROX, painted the joins with ScotchKote, wrapped them with 3M '23' stretch tape followed by reg elec tape. Then closed everything with heat shrink tubing. I'll keep my fingers crossed and check the joins for corrosion in 6 months or so. Thanks kata for the heads-up...

And thanks to all you guys for the replies

Edited July 10, 2011 by kloghead

[electau]

Aluminium to copper connectors are readily available from suppliers within the elecrical industry. Do a search for suppliers on the internet.

Crimp links and crinplugs also termination pin type lugs. Al to Cu.You will require a crimping tool for correct termination.

[kloghead]

electau--thanks so much for the helpful suggestion. Why didn't I think of (doing) that?

"Thanks for the replies, amigos. I spent hours on the web yesterday researching this situation and my eyeballs are about to fall out "

Last month I sent queries to 'GardnerBender UK", "Cabletrix UK" and four others. Not one of them even replied. A fellow from "Alcopstore" (in the states) who sells "Alumiconn" connectors did reply but they have no connectors large enough. And I didn't find any Thai or SE Asia sources for what I need. Not even the outrageously expensive RS have a suitable product.

Maybe you can give me a name or two?

Edited July 11, 2011 by kloghead

[T_Dog]

Kloghead.. You are right in worrying about this. I've seen aluminum coaxial hardline terminated to dissimilar connector material fail in less than a year in milder climates than Thailand. Standard procedure was to terminate all our hardline using one of two greases, only one of which I remember the name of. I know this would be difficult to find in Thailand but it would help greatly. You need to keep the air and possibly water (the electrolyte) off the dissimilar metal interface otherwise oxidation will occur.

http://www.idealindustries.com/prodDetail.do?prodId=noalox

[electau]

electau--thanks so much for the helpful suggestion. Why didn't I think of (doing) that?

"Thanks for the replies, amigos. I spent hours on the web yesterday researching this situation and my eyeballs are about to fall out "

Last month I sent queries to 'GardnerBender UK", "Cabletrix UK" and four others. Not one of them even replied. A fellow from "Alcopstore" (in the states) who sells "Alumiconn" connectors did reply but they have no connectors large enough. And I didn't find any Thai or SE Asia sources for what I need. Not even the outrageously expensive RS have a suitable product.

Maybe you can give me a name or two?

You could try the PEA?MEA first or try the Bangkok Yellow pages for a supplier. Burndy and Thomas and Betts manufacture them and sell them through electrical suppliers.

Edited July 11, 2011 by electau