A serious hazard for persons is the accidental rupture of enclosures
due to external mechanical impacts, which can expose live parts and
trigger explosive atmospheres. Enclosures, therefore, must have the
capability to protect their own contents. Such ability is specified by
the international IK code,4 which indicates the degree of protection
against harmful impacts. The IK code rates enclosures through the
code letters IK followed by the characteristic group numeral (00 to
10), indicating an impact energy value in joules (see Table 2.1).