Automotive Wire & Wiring Guide from TESSCO

Automotive Wiring Guide from TESSCOInstallation of wireless devices, audio, emergency equipment, or other accessories in a vehicle can sometimes be a daunting task. With TESSCO's exclusive Wireless Solutions® installation accessories, you'll get the highest quality at competitive prices for a good job the first time.


Typical Low Voltage Wire Sizes Guide

Air Conditioning- 10 GAUGE Heater Switch- 10 GAUGE
Alternator- 10 GAUGE Horn Button- 13 GAUGE
Ammeter- 10 GAUGE Horn To Relay- 10 GAUGE
Cigarette Lighter- 14 GAUGE Ignition Switch- 12 GAUGE
Clock- 18 GAUGE Low-Amps Circuits- 18 GAUGE
Coil Wire- 16 GAUGE Parking Lights- 16 GAUGE
Dome Lights- 16 GAUGE Radio To Fuse Blocks- 14 GAUGE
Driving Lights- 14 GAUGE Single Bulbs- 18 GAUGE
Gauges- 14 GAUGE Starter To Relay- 16 GAUGE
Generator (Charging)- 10 GAUGE Stoplights- 16 GAUGE
Generator To Starter- 16 GAUGE Tail Lights- 16 GAUGE
Headlight Circuit- 14 GAUGE Turn Signals- 16 GAUGE
Headlight Switch To Fuse Block- 12 GAUGE CD To Fuse Block- 14 GAUGE
Heater Leads- 16 GAUGE Windshield Wiper & Washer- 14 GAUGE

For safety and best resultsWhen circuit is longer than 10 feet, always use the next larger gauge size, which is the next lower even number.


Wire Gauge Selection Table 12 Volt Circuit

AMPS 3' 5' 7' 10' 15' 20' 25'
0 to 5 18 18 18 18 18 18 18
6 18 18 18 18 18 18 18
7 18 18 18 18 18 18 18
8 18 18 18 18 18 16 16
10 18 18 18 18 16 16 16
11 18 18 18 18 16 16 14
12 18 18 18 18 16 16 14
15 18 18 18 18 14 14 12
18 18 18 16 16 14 14 12
20 18 18 16 16 14 12 10
22 18 18 16 16 12 12 10
24 18 18 16 16 12 12 10
30 18 16 16 14 10 10 10
40 18 16 14 12 10 10 8
50 16 14 12 12 10 10 8
100 12 12 10 10 6 6 4
150 10 10 8 8 4 4

2

200 10 8 8 6 4 4 2



For more information contact TESSCO at 800-472-7373 or by email.

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