# 12 wire stranded or solid is rated at 20 amps.
A #12 copper wire with an insulation rating of 60, 75 or 90 degrees C is rated at 20 amps. This holds true whether it is solid or stranded.
You should use # 10 gauge wire, solid or stranded.(by Code)
It does not matter whether the wire is stranded or solid a #12 conductor is rated at 20 amps. Stranded wire is usually used in conduit systems as the wire is easier to pull around bends in the conduit as compared to solid wire.
The current (amp) capability is determined by the wire size in gauge, rather than the voltage rating stamped on the insulation. The most basic rating is 20 Amps for 12 gauge and 15 Amps for 14 gauge wire; however, it can get more complex than that for long runs of wire or for wires run through conduit with other wires. Hire an electrician if this sounds bewildering.
That is 10 amp wire.
on a 4000 watt amp the best gauge wire woul be between 2 and 0
12 gauge wire is required to be protected with a 20 amp max breaker. 10 gauge is required for a 30 amp breaker.
14 American Wire Gauge (AWG).
The ampacity or amp rating of all wire is rated by the size of the wire. NM (non-metallic sheathing) wire is no different. In household wiring 14 gauge wire must go on a 15 amp breaker/ 12 gauge goes on a 20 A and 10 gauge goes on a 30 Amp.
#6 gauge copper