I hold an electrical certification in the EU, though I'm not currently practicing.
A quick point: transient surges are usually fine. Both cables and circuit breakers are designed to fail (trip or burn out) under sustained overloads. For example, a 16A Class C circuit breaker might take around an hour to trip with a constant 17A load, but a ~80A load would trip it ~instantly.
PS: Of course, everything is a matter of integration over time (heat dissipation in cables mostly).