I am splicing Number 4 wire in a junction box - I ran indoor Romex No 4 from Main Panel into a junction box where I will splice to No 4 Aluminum individual wires. I bought wire lugs to connect them. How do I keep the wires separated? They will just hang in the junction box...

 

The individual conductors need to be in conduit.

Perhaps I don't understand your question. Insulated wires from different splices can touch.

 

You will need special connectors such as Polaris to connect aluminum to copper. In addition to Polaris there are special split bolts for Al to Cu.
Can you post a picture of the lugs and box. http://www.doityourself.com/forum/li...rt-images.html

 

Like PCboss stated, they can touoch, that isn't a problem.

The splices must be insulated.

You need aluminum to copper split bolts......OR......Polaris (or Ilsco) pre-insulated connectors, like Ray said.

 

Here's a pic of the lugs I'm using...

 

It's hard to tell for sure, but they look to be Al/Cu tin plated aluminum split bolt connectors with a separator to keep the aluminum wire and copper wire from coming directly into contact. These are usually insulated with rubber tape followed by vinyl tape.

 

The ends of the wires are stripped. One conductor is above the bar, the other below the bar. The nut is tightened. Rubber tape is then wrapped around the split bolt until all the metal is covered. Then vinyl tape is wrapped all over the rubber tape.

While expensive, the pre-insulated connectors are faster and easier. They are less messy if changes need to be made also.

 

A tip. The first wrap of tape on a split-bolt should be vinyl applied backwards, that is with the adhesive outward. Ideally you would use either cambric or fiberglass high-voltage tape but it makes little sense to buy that expensive tape for only one job. After this first layer of backwards tape you then follow up with the rubber tape (or, if you have it, Scotchfil compound) and layer the rubber over and again for at least three full layers being certain that ALL metal has three layers of rubber. Then you can use a single complete layer of plastic over the rubber.

The rubber will self-vulcanize to a solid mass of rubber but using the first layer of plastic (or the other I mentioned) will keep the rubber from filling all the nooks and crannies of the split bolt and will make it possible to remove the mass of rubber and plastic if ever necessary.

Trust me, BTDT.

 

Furd, for years we always stripped the vinyl off and wrapped it around first then put the rubber tape which was left around that then wrapped it with the vinyl, much easier your way.
Geo

 

I haven't even heard mention of varnished cambric tape in over 30 years, is it still available? I'd guess if it's still available it would be a specialty item and only available at some supply houses.

 

I have a couple of rolls that must be at least that old but yeah, it is still available. Ungodly expensive though, over thirty bucks a roll. Do a Google for several suppliers, including Amazon.