Requirements for All Lines
33.3 Ground Connections
A. Effective Grounds
Supply equipment of the following types, when grounded to conform to requirements of this order or for any other reasons, shall be effectively grounded:
Neutral conductors of low voltage supply circuits, (0-750 volts, see Rule 58.3-C1);
Neutral conductors of supply circuits exceeding 750 volts;
Transformer cases grounded in accordance with Rule 58.3-C3.
B. Independent Ground Connections
Ground connections for equipment of any one of the types listed in Rule 33.3-A shall not be interconnected with ground connections for equipment of any other type listed therein, except:
In common neutral systems the neutral conductors of 0-750 volt supply circuits and of supply circuits of 750-5000 volts may be interconnected and grounded in accordance with the provisions of Rule 59; and
A ground connection for a set of lighting arresters may be interconnected with:
A ground connection for neutral conductor of the circuit protected by the set of lighting arresters ,
The cable sheath or body of the cable pothead where the cable conductors are connected to the circuit protected by set of lighting arresters,
Metallic conduit enclosing conductors of the circuit protected by the set of lighting arresters,
Transformer cases grounded in accordance with Rule 58.3-C3 where transformers are connected to the circuit protected by the set of lighting arresters, and
The ground connection of another set of lighting arresters, provided the circuits protected are of the same voltage classification.
Where more than two sets of lighting arresters on supply circuits of the same voltage classification are installed on a pole or structure, and their ground terminals are interconnected at the top of the ground connections, two complete and effective ground connections will be considered sufficient for the purpose of this rule. Connection to an effectively grounded cable sheath or conduit of a circuit protected by the lighting arresters will be considered as one of these two effective ground connections.