Loose wire in RV electrical is a scandal. Holes in aluminum with set screws are NOT MEANT for fine stranded wire. The only exception is the rare example that has a permanent metal TANG permanently attached covering the screw entrance. I've got way too much experience in this area. There are Chinese terminal blocks for sale that do not have the tang. Avoid them when using fine stranded wire.
Heating of wires causes annealing making the copper as soft as mud. Tin plating disappears then oxygen turns the aluminum surface into aluminum oxide. Resistance rises like crazy.
The aluminum bar then needs to go to the aluminum recycler and the copper wire needs to be new-penny bright when it slips into a replacement aluminum.
To live dangerously is to poo-pooh the need to tighten all panel screws the moment a rig leaves the dealership. Then several months later do it again. Crushed wire is OK as long as the copper continuous to look like a brand new penny.
BTW the so-called anti-oxide slop which is 500% overpriced at hardware stores is a ripoff. It is pure cosmoline that in bulk costs $156.00 for a 55-dollar drum.
COSMOLINE by itself cannot remove oxide. You would be just as well-off smearing margarine onto the work. Silicone grease preserves better but the parts MUST start out brand new. The tin coating on the bus must not be damaged.
Squeeze set screw conductors demand THHN type wire with far fewer but much thicker strands of copper. This type of wire is FAR FAR more resistant to crushing and becoming loose when coupled to a set screw tinned aluminum buss.
My findings are a result of many years of experience and not guesswork or theory of parroting Chapter 9 section C sub section a)21 of some idiot code. If your panel catches fire after reading and ignoring this tip -- blame no one but yourself. This is exactly the reason why the NEC stays well away from RV electrical. The level of ignorance is utterly absurd.
