Conductor size

A comparison of standard mm² wire sizes and standard AWG wire sizes. AWG decreases as wire size increases, mm² increases as wire size increases.

Wires come in standard sizes depending upon the location. The proper wire size for a particular circuit depends on two important considerations:

1. The amount of current that they can safely carry given the conditions in which they will be used.
2. The amount of voltage that will be lost under operation, which is called voltage drop

The wires for an off-grid system must will be sized and selected based upon the load evaluation and the physical evaluation for a particular site. This process must be done in conjunction with the sizing and selection of the overcurrent protection device - see Wire and overcurrent protection sizing and selection for more information.

The two most common standards for wire size are American Wire Gauge (AWG) and mm². These two systems are not directly equivalent.

Standard AWG	Cross sectional area	Standard metric equivalent
18 AWG	.82 mm²	1 mm²
16 AWG	1.31 mm²	1.5 mm²
14 AWG	2.08 mm²	2.5 mm²
12 AWG	3.31mm²	4mm²
10 AWG	5.26 mm²	6 mm²
8 AWG	8.37 mm²	10 mm²
6 AWG	13.3mm²	16mm²
4 AWG	21.2 mm²	25 mm²
3 AWG	26.7 mm²
2 AWG	33.6 mm²	35 mm²
1 AWG	42.4 mm²	50 mm²
1/0 AWG	53.5 mm²
2/0 AWG	67.4 mm²	70 mm²
3/0 AWG	85 mm²	95 mm²
4/0 AWG	107 mm²	120 mm²

Cable size

Cables are typically designed to contain all of the wires that are needed for a particular circuit. Therefore there are many different configurations of cable that vary based upon the size of the wires, the number of wires, and the color of the wires. Cables will be labeled with the size of the current carrying conductors and the quantity. For example a cable with three 12 AWG wires will be labeled "12/3". A cable with three 2.5mm² will be labeled 2.5mm²/3. Equipment grounding conductors (EGCs) are generally excluded from the cound of conductors and should be specified seperately.