Stroj mora biti tako načrtovan, izdelan in, kjer to ustreza, nameščen na premičen podstavek, da je zagotovljeno, da ob njegovem premiku njegova stabilnost ne bo ogrožena zaradi nenadzorovanih nihanj njegovega težnostnega središča ali njegova konstrukcija izpostavljena prevelikim pritiskom.
Machinery must be so designed, constructed and where appropriate placed on its mobile support as to ensure that when moved the uncontrolled oscillations of its centre of gravity do not affect its stability or exert excessive strain on its structure.