Cable Size Chart
The Gauge Guide bullets will help you determine the overall size (including insulation) of an unmarked cable.
Actual diameters may vary depending on the age, make and insulation thickness of your cable.
Check out our Printable Version PDF to more accurately measure the end of your cable against Gauge Guide bullets.
If you are still not sure, the most accurate way to measure your cable is to determine the area in mm² of the copper conductors.
As an example, let's assume we want to know the area for 3mm auto cable:
- Count the total number of strands. (14)
- Measure the diameter of one of the strands. (0.32)
In this case we have 14 strands @ 0.32mm each. Knowing this we now do the following calculations:
- Square (multiply by itself) the diameter of each strand (0.32 × 0.32 = 0.1024)
- Multiply this result x (Pi) 3.14 (0.1024 x 3.14 = 0.321536)
- Divide this result by 4 (0.321536/4 = 0.080384)
- Multiply this result by the number of strands (0.080384 x 14)
Therefore the approximate area for 3mm auto cable is:
- 1.13mm²
|
Auto Size |
Nom Area mm² |
Nom O.D.mm |
Amp Rating |
Part # Prefix |
Gauge Guide |
|
3mm |
1.13 |
2.2 |
20 |
C16 |
 |
|
4mm |
1.84 |
2.6 |
28 |
C14 |
 |
|
5mm |
2.90 |
3.0 |
37 |
C12 |
 |
|
6mm |
4.59 |
4.0 |
48 |
C10 |
 |
|
Auto Size |
Nom Area mm² |
Nom O.D.mm |
Amp Rating |
Part # Prefix |
Gauge Guide |
|
2mm |
0.5 |
1.5 |
10 |
C18TW |
 |
|
3mm |
1.0 |
2.0 |
15 |
C16TW |
 |
|
4mm |
2.0 |
2.55 |
20 |
C14TW |
 |
|
Auto Size |
Nom Area mm² |
Nom O.D.mm |
Amp Rating |
Part # Prefix |
Gauge Guide |
|
3mm |
1.13 |
3.8 |
20 |
C16DI |
 |
|
4mm |
1.84 |
4.2 |
28 |
C14DI |
 |
|
5mm |
2.90 |
4.9 |
37 |
C12DI |
 |
|
6mm |
4.59 |
5.7 |
48 |
C10DI |
 |
|
Auto Size |
Nom Area mm² |
Nom O.D.mm |
Amp Rating |
Part # Prefix |
Gauge Guide |
|
3mm |
1.13 |
7.0 |
20 |
C7HT |
 |
|
Auto Size |
Nom Area mm² |
Nom O.D.mm |
Amp Rating |
Part # Prefix |
Gauge Guide |
|
2 x 2mm |
0.44 |
2.4 x 4.8 |
2.5 |
C20T |
 |
|
2 x 2.5mm |
0.75 |
2.6 x 5.1 |
5 |
C18T |
 |
|
2 x 3mm |
1.13 |
2.6 x 5.9 |
10 |
C16T |
 |
|
2 x 4mm |
1.84 |
3.1 x 6.7 |
15 |
C14T |
 |
|
Auto Size |
Nom Area mm² |
Nom O.D.mm |
Amp Rating |
Part # Prefix |
Gauge Guide |
|
2 x 2mm |
0.56 |
3.1 x 5.1 |
8 |
C2/18 |
 |
|
2 x 3mm |
1.13 |
3.3 x 5.5 |
16 |
C2/16 |
 |
|
2 x 4mm |
1.84 |
3.8 x 6.3 |
22 |
C2/14 |
 |
|
2 x 5mm |
2.90 |
4.5 x 7.4 |
29 |
C2/12 |
 |
|
2 x 6mm |
4.59 |
5.7 x 9.6 |
38 |
C2/10 |
 |
|
2 x 8 B&S |
7.71 |
7.1 x 12.5 |
59 |
C2/8 |
 |
|
2 x 6 B&S |
13.5 |
8.8 x 16 |
82 |
C2/6 |
 |
|
2 x 2 B&S |
32.07 |
13.4 x 24.6 |
150 |
C2/2 |
 |
|
Auto Size |
Nom Area mm² |
Nom O.D.mm |
Amp Rating |
Part # Prefix |
Gauge Guide |
|
3 x 3mm |
1.13 |
5.7 |
14 |
C3/16 |
 |
|
3 x 4mm |
0.92 |
6.7 |
12 |
C4/16 |
 |
|
5 x 2mm |
0.56 |
6.0 |
7 |
C5/18 |
 |
|
5 x 3mm |
1.13 |
4.0 |
11 |
C5/16 |
 |
|
5 x 4mm |
1.84 |
8.2 |
15 |
C5/14 |
 |
|
7 x 2mm |
0.56 |
6.7 |
5 |
C7/18 |
 |
|
7 x 3mm |
1.13 |
7.7 |
10 |
C7/16 |
 |
|
7 x 4mm |
1.84 |
8.9 |
14 |
C7/14 |
 |
|
2 x 6mm 1 x 5mm 1 x 3mm |
4.59 2.90 1.13 |
10 |
38 37 20 |
C4/6653 |
 |
|
Auto Size |
Nom Area mm² |
Nom O.D.mm |
Amp Rating |
Part # Prefix |
Gauge Guide |
|
- |
0.44 |
6.3 |
3 |
C SEC.14208 |
 |
|
- |
0.75 |
6.8 |
6 |
C2SC24/.2 |
 |
|
- |
0.50 |
5.8 |
3 |
C2SC7/.3-100 |
 |
|
- |
0.44 |
4.8 |
3 |
C4/SEC.5/100 |
 |
|
Auto Size |
Nom Area mm² |
Nom O.D.mm |
Amp Rating |
Part # Prefix |
Gauge Guide |
|
8 B&S |
7.71 |
5.5 |
74 |
C8 |
 |
|
6 B&S |
13.5 |
7.2 |
103 |
C6 |
 |
|
4 B&S |
20.26 |
8.3 |
135 |
C4 |
 |
|
3 B&S |
26.45 |
10.2 |
168 |
C3 |
 |
|
2 B&S |
32.07 |
11.3 |
188 |
C2 |
 |
|
1 B&S |
39.55 |
12.1 |
210 |
C1 |
 |
|
0 B&S |
49.00 |
12.7 |
246 |
C0 |
 |
|
00 B&S |
64.15 |
14.5 |
292 |
C00 |
 |
|
000 B&S |
83.19 |
16.4 |
335 |
C000 |
 |
|
Auto Size |
Nom Area mm² |
Nom O.D.mm |
Amp Rating |
Part # Prefix |
Gauge Guide |
|
- |
1.0 |
2.8 |
10 |
C32/.2 |
 |
|
- |
1.5 |
3.3 |
15 |
C30/.25 |
 |