Conversion table: The American Wire Gauge [AWG] and metric wire standards
40 Feet 20 AWG High Temperature PTFE Silver Plated Wire 0.5mm2: Amazon.com: Industrial & Scientific
Gauge of Electrical Cables according to AWG Standard - ZMS CABLE
Wire Sizes - AWG versus Square mm | Copper wire, Wire, Chart
Awg To mm2 | PDF | Wire | Manufactured Goods
AWG (American Wire Gauge) To Metric (Sqmm Millimeters Squared) Conversion Table | PDF
I bought a roll of 13-14 AWG wire (2.5mm2). According to this chart, I would be safe running a wire from my battery (which is next to my firewall), through the firewall,
MM2 To AWG Conversion Table JAR UK Industries V1.0 August 2018 JAR01A | PDF | Wire | Manufactured Goods