Is this not the outdoor lighting forum? I'm new, but I think the last three posts were really out of line. We aren't talking line voltage here, guys. Splicing 8-2, 10-2, 12-2, and even 14-2 wire together at a hub connection is pretty common in a low voltage landscape lighting system in order to achieve an even voltage delivery to the fixtures.
Braphael: I have used large common wire nuts with silicon, King safety nuts with silicon paste inside, copper crimps and silicon potting compound for many years with good success. The key is to make sure you have a good tight mechanical connection before you put the nut on. Look at it this way, the wire nut is not to connect the wire but to protect the wire connection. Then make sure the water proofing compound (whatever you end up using) completely covers the exposed wire as you screw on the wire nut.
I have installed low voltage landscape lighting systems for 15 years like this and if you use the non-hardening compounds like silicon, the connections will stay clean and dry for many years. I have pulled old connections apart after they have been in the ground for 10 years or more and the copper is still shiny.
I have not seen a system of soldering that works as well in all the different places and situations where wire connections need to be completed, so I abandoned soldering splices years ago. There maybe something new out there, but I’m not familiar with it.
Stay completely away from the quick connectors or anything that uses spikes to penetrate the insulation. I don’t care who makes them. Unless that spike has silicon or something like it all around it, the connection will eventually leak moisture and the moisture will eventually find its way into the fixtures and sockets.
Hope this helps.
Bill