[Mr V]

A few thoughts from someone who works on 12v electronics all the time as a automotive/MD truck technician.

Speaking of wire the best is cross-linked polyethylene it is the only type of wire endorsed by SAE for underhood automotive use and has much better heat and abrasion resistance. Even the newest solder'er can't melt nor damage the insulation, Ok maybe if you use an open flame. It is called out as *xl with TXL having the thinnest insulation, SXL the thickest and GXL in-between. SGX is super heavy insulation available in 6ga or larger for "battery cables" and is what is used on the more recent Anderson Power Pole pigtails. It is identifiable by the slippery waxy feel to the insulation if it isn't marked.

The translucent PVC "stereo" wire is the worst stuff you can get. The reason it is thicker and heavier yet more flexible than standard PVC wire marketed as "primary wire" (GPT) is because the transparent insulation has a lower melting point and abrasion resistance due to its' softness.

There are boots designed to provide insulation for contacts such as the main breaker and PD, I use them all the time, and they are available from companies such as TSC.

I'm not sure what is meant by "motor protectors" any motor protection needs to be internal to the motor in the form of a thermistor. Fuses and circuit breakers fall under the category of circuit protection. They are not to protect what ever the load is but instead are to protect the wire from the load.