250.4 (A) grounded System

5) Effective Ground-Fault Current Path

Electrical equipment and wiring and other electrically conductive material likely to become energized shall be installed in a manner that creates a low-impediment circuit facilitating the operation of the overcurrent devices or ground detector for high-impedance grounded system.

4) Bonding of electrically conductive materials and other equipment

Non-current carrying electrically conductive materials that are likely to become energized shall be connected together and to the electrical supply source in a manner that establishes an effective ground-fault current path.

1) Electrical system grounding

electrical systems that are grounded shall be connected to earth in a manner that will limit the voltage imposed by lightning, line surges, or unintentional contact with higher-voltage lines and that will stabilizes the voltage to earth during normal operation.

2) Grounding of Electrical Equipment

non-current carrying conductive materials enclosing electrical conductors or equipment, or forming part of such equipment, shall be connected to earth so as to limit the voltage to ground on these materials.

3) Bonding of Electrical Equipment

non-current carrying conductive materials enclosing electrical conductors or equipment, or forming part of such equipment, shall be connected together and tot he electrical supply source in a manner that establishes an effective ground-fault current path.