Stewie
If I was helping a mate out on his build, yes, if I did something stupid, I would wear the cost. Same as at any other time in life. What annoys me is this attitude of entitlement now that if anything goes wrong for you, the first line of response is to see who you can get money from to compensate you for your own stupidity.
As i read it The OP wants to get mates in to do him a favour, not for wages. Such help is not required to be regulated. And if you are worried of being in the position of being sued by your mate, well, hes hardly a mate.
Id still like anyone to show me the legislation that such help by a mate must be insured under such cirumstances?
And to hell with the nanny state - I have always, and will continue, to bring whom I like onto my build sites. ITs my property, not anyone elses. I have enough common sense to keep people out of danger. Its not rocket science.
However, a friend could for example run cables, provided it was under supervision of an electrician, on site at the time.
You dont have to be supervised by anyone to run cables that arent connect to supply, or to fix conduit/fixtures etc that arent yet connected to the water supply. But it has to be able to be inspected by a licensed plumber/sparky so that he is satisfied to sign off on it.