Wire gauge (AWG) → amperage

AWG copper circular mils, chassis ampacity, and a 12 V / 24 V voltage-drop calculator for truck electrical work — sources cited on the page.

AWG (American Wire Gauge) rates wire size: the smaller the number, the thicker the wire, and the more amperage it can carry.

The table below lists the wire’s maximum thermal limit (never exceed it, no matter the run length). The calculator above gives the practical amp rating once cable length is factored in, so voltage drop doesn’t starve the load — usually a lower, more realistic number for real-world use.

Example: for a pump drawing 15 A at 12 V over a 20 ft run, use the calculator to find the minimum recommended gauge — not the table alone.

Voltage-drop calculator (12 V / 24 V)

Enter AWG, system voltage, one-way cable length, and allowed drop. Result is max current for copper using the cited DC formula.

AWGSystem voltageOne-way length (ft)Allowed drop

Max current (voltage-drop limit)

11.5 A

Source: DC copper voltage-drop formula I = (CM × VD) / (2 × L × 10.75) — same form as common chassis/ABYC-style charts

AWG reference table

Absolute safety limit — never exceed these amps. The calculator above is the practical recommendation for your case (length + voltage + allowed drop).

AWG	Circular mils	Typical chassis continuous
18	1,620	10 A
16	2,580	15 A
14	4,110	20 A
12	6,530	25 A
10	10,380	40 A
8	16,510	55 A
6	26,240	75 A
4	41,740	95 A
2	66,360	130 A
1	83,690	150 A
1/0	105,600	170 A
2/0	133,100	195 A
4/0	211,600	260 A

Source: AWG copper circular mils (ASTM B258 / standard wire tables) · Typical continuous chassis ampacity column aligned with SAE J1128-style automotive wiring charts (bundled/chassis — not building NEC)

Chassis ampacity is a bundled/automotive rule of thumb — not NEC building wire. Fuse to protect the conductor; voltage drop may require a larger gauge than chassis ampacity alone.

Related electrical fault codes

Wiring and supply issues often show up first as sensor or powertrain codes.

Electrical system overview

Search “wire stripper crimper kit” on Amazon(affiliate link)

Opens Amazon.ca search results — not a confirmed product fit. Verify with the seller before buying.