[DonRotolo]

If we keep it up like this, we'll eventually get there. This is good.

Temperature: Cold usually is not an issue, and any wire we'd encounter is plenty good at 0C (32F). Hot is the one we need to watch. "normal" wire is good from 0C to maybe 60C, maybe 75C, and that's generally fine for FIRST stuff. Hot is often less than 60C here. But when wiring near things that get hot, try to stay away, or be sure you understand how hot it can get and use appropriate wire. Automotive wire is generally -40C to 120C. It isn't the Wire that's rated, it's the insulation! Some wires can exceed 400C happily, but these don't come cheap.

Voltage: We do not usually see anything in excess of 24 volts, and doubling that for a safety factor still leaves us with just a few mils of insulation thickness necessary. The conclusion is that the insulation is more for mechanical protection than for voltage-arc resistance. We do not use magnet (enamel-coated) wire because the coating is not mechanically robust, not because it can't handle the voltage punch-through.

Tape: 3 layers of Scotch 33 tape is good for at least 250 Volts. One layer is easily OK for 48 volts, but you want best practices, not minimums, right? Tape must be UL approved, or it can only be used for identifying wires. For example, masking or duct tape has no recognized insulating power. Duct tape makes a dandy chafe guard though.

There are tapes available in greater thicknesses to accommodate higher voltages.

Tape temperature rating is assumed 0C - 40C unless marked (or check the manufacturer specs). It might be better, but if unknown, assume the worst. Cheap tape is awful stuff, the adhesive bleeds and ages. Scotch "33" is the standard, or perhaps "88" or their colored tapes "35".

Markings: I *Believe* UL-approval requires the wire to be marked with gauge, insulation type & voltage rating, and manufacturer. Good wire is always marked. Cheap wire may not meet UL standards, you get what you pay for. It is often good-enough, and I have seen very high-quality wire without markings, particularly if part of a cable assembly (e.g., inside an extension cord) having markings on an outer insulating layer. Also very small wires are impractical to mark. 24 ga is not very small.

Contrary to something i wrote before, I just remembered that safety ground wires are OK to be uninsulated, since they are intended to carry fault currents. If insulated, it must be green or marked green at each end.

I didn't mention heat shrink before. It is almost a replacement for manufactured insulation, but better used for marking, additional mechanical protection, and bundling. On very small wires it does replace tape. In my book it is just as good as low-end wire insulation, others may differ in that opinion.