Joe,
Proper maintenance of electrical installations is a key component of ongoing compliance with the NEC.
The maintenance and repair of existing electrical systems does not appear to be within the scope of the NEC. The scope statement in 90.2(A) seems to indicate that the code only applies to new installations or the installation of new equipment in existing facilities. NFPA 70B covers the preventive maintenance for industrial type electrical systems and equipment. Maybe we need a standard like that for other occupancies.
Don
