Terminating an old aluminum AWA cable

[EXC]

Hi
Can any body advise on terminating an old Alu armourd cable in to a 100A swtch fuse with screw terminals?
I have in the past used Alu lugs crimped using that Alu compound,but that was a large cable and was bolted .
This cable is a triangular core 50mm and did have pin lugs in screw terminals before it burnt out ( old 70's install) so my question is can you get Alu pin lugs and are they ok to put in a brass screw terminals as Alu expands at a diffrent rate then brass so will it become loose after time ?

 

[Top Cat]

Hi EXC, great question. I am old enough to remember using aly cable, trouble is i am old enough to forget what i used to do!

Well that was a lot of help!

 

[netblindpaul]

Just use normal lugs, treat as Cu cable, BUT, treat every interface between dissimilar metals wit Bicon X1, or Densal paste, & ensure that the ends are corretly prepped 1st

 

[Engineer54]

Just use normal lugs, treat as Cu cable, BUT, treat every interface between dissimilar metals wit Bicon X1, or Densal paste, & ensure that the ends are corretly prepped 1st

He can't use lugs, as he has stated he is terminating into Screwed terminals, so he needs to find an appropriate pin type crimp, ....trouble is i not sure they make one for a 50mm cable.

 

[EXC]

Thank you for you replys but I dont think I can use copper lugs ,I found this-
NOTE - Copper terminal lugs cannot be used to terminate an aluminium conductor. Aluminium conductors will thermally expand greater than copper conductors for a given temperature, therefore, under load, the copper will act to constrict the aluminium, causing permanent extrusion of the aluminium from the joint which will ultimately lead to a loose connection and potential failure of the joint.

 

[Knobhead]

With it being a shaped conductor about the only way you’ll get it to sit snug in the terminal is file it to shape. I know it will reduce the CSA but if you can’t get the correct pins I can’t see an alternative.
The last time I did it I was still an apprentice.

 

[benji]

why not use bi-metalic crimp pins

cembre mta50c ?

 

[johnboy6083]

Cheers benji, you learn something every day.

One thing I wanted to ask was, how strong is the joint between the Ali and the Cu? Do you have to really make sure the conductors are set in place to avoid snapping the pin off?

 

[EXC]

Cembre MT50 , thanks Benji I think that's just the thing , might even have a former in the stores to get the triangular core in to the round lug or vice-versa MTA50C Copper Pin Aluminium Barrels - £38.76 : Top Cable Accessories not cheap though ,and why do lug manufactures sell them in packs of three ,when you need 4?
Anyway ,thanks for all your inputs.

 

[Engineer54]

Cembre MT50 , thanks Benji I think that's just the thing , might even have a former in the stores to get the triangular core in to the round lug or vice-versa MTA50C Copper Pin Aluminium Barrels - £38.76 : Top Cable Accessories not cheap though ,and why do lug manufactures sell them in packs of three ,when you need 4?
Anyway ,thanks for all your inputs.

That's an extortionate price for 3 X 50mm pin crimps... I'd be looking for alternative methods myself, along the lines from netblindpaul's post...