AC Wiring rules for switched mains output device
Is there freely available information which may answer these questions?

In the US, the answer is no. Some of the applicable codes and standards are not easy to obtain without purchasing them.
The National Electrical Code, NFPA 70 (NEC) is published and offered for sale by the National Fire Protection Association. It can be read online, but not downloaded. It is available to be borrowed in many public libraries.
The NEC is the basis for all local wiring regulations. Each individual locality has its own rules. Those rules mostly cover only permits, inspection, enforcement etc. but some add or delete details with respect to NEC. Those rules are often freely available online and some provide downloadable versions of NEC.
Electrical devices are generally required to conform to applicable standards. Those standards are generally published by Underwriters Laboratories (UL). UL standards are offered for sale and not widely available otherwise. Electrical devices are generally required to be &quot;listed&quot; and &quot;labelled&quot; as meeting applicable standards. Listing must be done by and labelling authorized by a nationally recognized testing laboratory (NRTL) as determined by OSHA.