Egg AC / DC Wiring

[Art VanDelay]

Is there a down side to using 12 AWG 500' Stranded THHN Copper Conductor wire inside a camper?

Is there a plus side?

[Matt in SV]

No problem with stranded wire. I used mostly farm grade oil/water resistant extension cords from OSH with the connectors cut off for both the AC and DC runs. The gauge depends on the length, current, and tolerable voltage drop.

Some of that wire has a molded insulation that's difficult to strip.

Regards

Matt

[steve dunham]

THHN wire is 600 volt 90 deg. centigrade building wire for use in DRY locations only.
It's 90 deg rating allows for a higher ampacity in sizes #8 or larger. Sizes #14,#12, and #10 , use the standard ampacity tables (NEC 310-16)(SEE NOTES) . THHN has a thin layer of insulation (2 MIL) plus a nylon jacket. They also make a THHN , THWN, MTW rated wire which is rated for 90 deg ,dry and wet locations , gas and oil resistent and is allowed for use in machine tool wiring. The size of the wire and the termination method used usually is the source of most problems. Voltage drop across the conductor is a problem with 12 VDC. wiring. A #12 copper conductor may be able to carry 20 amps but at 12VDC the voltage drop may be too large.
Limit the load (amperage) and length of the conductor and you can make it (# 12) work. I always use the 50 % rule I.E. 10 amps maximum load on a 20 amp conductor and limit wire lengths to about 25 ft. max.