So I'm adding a subpanel for my attached garage. 100 amp panel, so I was looking for 2-2-2-4 ser cable. Well There's nothing in the state available except at electrical supply stores and it's over twice as much as the big box stores, but you can't find it in big box stores. I have 60' of 4/0-4/0-4/0-2/0 ser cable that I got really really cheap. I also about 25' of 2-2-2-4. This stuff is like wrestling an anaconda but I can make it work, but I'd need to spice each end with the 2-2-2-4 to run into each of the service panels because there's no way I can get that 4/0 into the service and subpanel. Of course the breaker would only be for the 100amp. I've seen barrel splices that would work, but do you just leave them in the open air like the overhead service? How do you contain the spiced wire after insulating it? One spice would be in the floor joists above the panel in the basement and the other would be in the attic above the service panel, so not just hanging out in a room.