Dave wrote:

That's interesting, can you explain a little more. Do you mean isolating
transformers? (or opto-isolators?) I google'd and came up with isolators
to avoid earth loops but nothing about safety.

I think he means RCDs.....

Usual practice for small gigs is a 30mA rcd either at the generator (which
gives no discrimination), or several at thee distribution board.
I often add a 10mA unit just for the backline because backline tends to be
the root of all evil in this matter.

Do earth the generator frame with a spike, and DO bond the stage metalwork
to generator earth (it probably will be via some path anyway and you would
rather this didn't involve the screen of the audio snake....).

The spike is to protect you the generator operator in the event of an
internal fault imposing voltage between the generator frame and the earth
connection on the socket which is probably earthed elsewhere (like say the
stage).

The RCD(s) protect the musicians from faults in the distro and their guitar
amps (what never!).

Bonding the stage metalwork reduces possible earth loop impedance issues and
encourages faster disconnect times.

Really once you get past the genny it is all fairly standard event power
engineering.

HTH.

Regards, Dan.