Electrical
Cable Gauge / Ampacity
01 — Definition
How much current a cable can carry depends on the conductor cross-section (mm² or AWG), the type of insulation and the installation conditions. A larger cross-section takes more current and drops less voltage over distance. Bundling cables or running them in conduit lowers their ampacity, because the heat can no longer escape; and over long runs, voltage drop ends up starving the fixtures at the far end.
02 — In the field
On long power runs, size the cable up for voltage drop, not just to meet ampacity. A 100 m run on minimum-gauge cable can drop enough voltage that the fixtures at the end brown out or reset: calculate the drop, not just the current.