Connecting copper and aluminium conductors

[RalphChristie]

Any recommendations, methods, type of connections, etc. on connecting copper and aluminium? (380V to 66kV)
I am looking for advice on:
verhead conductors, (copper lines to aluminium lines)
:aluminium cables on copper overhead conductors,
:copper cables on aluminium overhead conductors,
:cables (copper cables on aluminium cables)

We have some problems with copper/aluminium connections - it doesn't last long.(just a few years)
There seems to be extra corrosion when you join it or some kind of chemical reaction between the two.

Thanks
Ralph

 

[tinfoil]

Whenever any two different metals are in contact, electrochemical differences at the molecular level will tend to cause an oxidation reaction on the less 'noble metal' (or as you said, 'corrosion')

To prevent this, most manufactures of electrical hardware produce lines of connectors that are tin-plated to minimize this effect, and that can also be used for aluminum-aluminum and copper-copper connections as well.

When you are shooping for connectors, just mention to your vendors that you may be joining Al to Cu, and they can point you in the right direction.

 

[stevenal]

Use pads to make the transition. Compress tin plated copper pads onto the copper conductor/cable, and aluminum pads on the aluminum. Wire brush the aluminum to remove oxide, but don't brush tin plated copper. Use oxide inhibitor and bolt together with stainless steel hardware. Make sure you use Belleville washers and torque to spec. Orient the connection so the aluminum is up and no other copper is directly above the connection, so that copper salts from the corroding copper will not wash over the joint. There is good information in either the Burndy or Anderson catalog, maybe in both.