In the uk, on building sites the "principal contractor" is responsible for site safety, and they must have insurance, which generally stipulates 110V (really 55-0-55V) on site for portable tools. So on most commercial sites anyone caught with a 240v tool will be dissmissed instantly.
HSE recommend the use of low voltage tools, but take a realistic view and recommend a RCD with 240V. Clearly self builders aren't going to have all 110V tools. You couldn't have and there isn't a law against 240V on site, as many big machines couldn't work on 110V.
It's interesting that hse allow 240v but are consficating pull-over mitre saws from work places.
