IP stands for Ingress Protection, and the two digits describe resistance to solids and liquids respectively. A rating of IP67 means the cable is fully dust-tight (6) and can withstand immersion in water up to one metre deep for thirty minutes (7). For a cable used outdoors several times a week, in rain, on wet ground, and plugged and unplugged in all weathers, this is the minimum standard worth looking for.

Lower-rated cables may handle light rain but are more vulnerable to moisture working into the connectors over time, which affects both safety and longevity. IP67 is also the rating referenced in IEC 62196 (the standard governing Type 2 connectors), so a cable carrying this certification has been independently tested to confirm it, rather than the manufacturer simply claiming weather resistance.