"This part of IEC 60079 ?C gives instructions@ principally of a technical nature@ on the repair@ overhaul@ reclamation and modification of equipment designed for use in explosive atmospheres; ?C is not applicable to maintenance@ other than when repair and overhaul cannot be disassociated from maintenance@ neither does it give advice on cable entry systems which may require a renewal when the equipment is re-installed; ?C is not applicable to type of protection ""m""@ ""o"" and ""q""; ?C assumes that good engineering practices are adopted throughout. NOTE Much of the content of this standard is concerned with the repair and overhaul of electrical machines. This is not because they are the most important items of explosion-protected equipment@ but rather because they are often major items of repairable capital equipment in which@ whatever type of protection is involved@ sufficient commonality of construction exists as to make possible more detailed instructions for their repair@ overhaul@ reclamation or modification."