connect al and cu wires together

[JCA1]

I have #6 CU wire that I have connected to with #6 AL wire to run power to an out building. I plan to use a 50A breaker in the main panel to feel the outbuilding, but have not installed it yet. Under my house I mounted a junction box and spliced the wires together with splicer lugs the electric supply house sold me for this purpose. These have a divider in the middle to prevent the two wires from touching and one flat blade set screw on each side to hold the wires. I used the antioxidant on the AL wire, and tightened both sides tight as I could with a regular screwdriver then wrapped the splices with about 8 wraps of electrical tape, and stuffed everything into the box. I have since been told by various sources that this was a bad idea and am "now" looking for more advice from seasoned pro's about this work of mine.

[HayZee518]

your use of the split bolt splice with the metal bar is correct. the split bolt connector should be marked Cu-Al if it is approved for aluminum/copper splicing. No 6 copper carries 65 amps. your use of #6 aluminum is a mis-nomer. for your aluminum wire to carry 65 amps it would need to be a #4 cable. normally aluminum goes one size higher for a given amps. #6 al is equivelant to #8 copper or 40 amps. #12 aluminum carries 15 amps. #10 al carries 20 amps etc.
As far as splicing the way you dis, first go with five layers of rubber splicing compound then four layers of friction tape and finally two layers of plastic electrical tape. Use the anti-oxidant on both conductors not just the aluminum.

[JCA1]

Ok, thanks very much, will do.

[Speedy Petey]

Originally Posted by JCA1

These have a divider in the middle to prevent the two wires from touching and one flat blade set screw on each side to hold the wires.

This does not sound like a split-bolt to me. It sounds like a Polaris connector without the outer rubber coating.
I will agree, 8 wraps of regular electrical tape is not enough. You do need rubber tape than regular vinyl tape. No one uses friction tape anymore.

Also, #6AL IS good for 50 amps. This is unless it is older TW type wire. If it is pretty recent wire than you are fine at 50A.

[Java_Bob]

No one uses friction tape anymore.

hey if you have some laying around why not...

[HayZee518]

The ideal splicing compound for joints is VARNISHED CAMBRIC. This, followed by a co-polymer tape, glass tape and a two part epoxy. This is beyond the realm of the everyday homeowner. So...............first coat is rubber splicing compound. This tape has a release layer that is removed before applying and is stretched over the joint in a criss cross fashion till 8 layers are built up. Next if you have friction tape a layer 4 layers thick, then plastic electrical tape. If you don't have friction tape double up on the plastic tape to four layers.

[JCA1]

Speedy, you are correct that it is not a split bolt, it's like a wire union or coupling per say. They are about 1.5" long with a hole on each end to stick the wire in and have a divider in the middle to prevent the two wires from touching end to end, and they have one flat blade set screw on each side to tighten the wires down with.

[HayZee518]

I drew several pictures of splicing devices for large diameter cables. I think the one you have is in the center bottom.

[JCA1]

You are correct

[JCA1]

Ok, I replaced the junction box with a 6x6x4, re did the connections, and wrapped with rubber tape so much that my #6 wires look like 3/4" pipe, then followed with several wraps of super33 electrical tape. I used the antioxidant compound on all the wires this time, not just the AL ones. I'm still getting some friction from another resource about this connection type, so....
Is there any real hazard with this type of connection?