Anything over 30ma 'can' kill hence why personal protection is 30ma and equipment protection is 100ma, Oh and I am currently running all my 240v equipment on site via an rcd which is legal and allowed by the HSE. One of the reasons 240v isn't used is because its not normally there or hooked up until near the end of the contracts for testing etc... but the main reason is of course safety and i hasten to add everybody else on site is useing 110v as they don't have access to the 240v.