Generator changeover switch

[plugwash]

if the generator has neutral and earth isolated i would advise joining them (isolated neutral and earth is a brilliant system for one or two tools but it renders rcds useless so isn't very smart for larger installations where the chance of a pair of faults is much higher)

then just connect the earth line from the generator to your earth system and add a rod so you aren't relying on the leccy cos earth if thier cable gets dug through etc

 

[Spark123]

Only ever join the Neutral to Earth when the earth electrode is connected and supply is through an RCD.
If the electrode + RCD are omitted, the N-'E pin' generator link fitted and a L - true E fault arose, the chassis of the generator will become live to 230v above true earth. A worrying thought.