It is commonplace for firecodes to tell us not to use extension cords. But for living in a rental, sometimes there is no other way to transmit datalines between rooms securely. A reasonable person would infer this fire code is talking about full AC current extension cords, since many of these cords aren’t rated for the full amperage provided by typical fuses.
I have always understood this to be about AC extension cords. When it comes to Ethernet extension cords, I assume it’s fine because they don’t carry any power. Though I’ve never bothered to ask.
For USB extension cords though, there is about 5V carried through the cords, maybe up to an amp typically (5W). Still nothing that would cause a fire.
What is the line though? Certainly fire codes must recommend a typical wattage for these cords? And they must be safe to run under doors as well?