34 Pa. Code § 39.361
The following words and terms, when used in this section and §§ 39.362-39.371 have the following meanings, unless the context clearly indicates otherwise:
Voltage-In general the highest effective voltage between the conductors of the circuit concerned, except that in grounded multiwire circuits, not exceeding 750 volts between outer conductors, it means the highest effective voltage between any wire of the circuit and the ground.
Voltage to ground-In ungrounded low-voltage circuits, the voltage of the circuit.
34 Pa. Code § 39.361
This section cited in 34 Pa. Code § 39.411 (relating to general provisions); 34 Pa. Code § 39.421 (relating to general provisions); 34 Pa. Code § 39.431 (relating to general provisions); 34 Pa. Code § 39.441 (relating to general provisions); 34 Pa. Code § 39.451 (relating to general provisions); 34 Pa. Code § 39.461 (relating to general requirements); 34 Pa. Code § 39.471 (relating to general requirements); 34 Pa. Code § 39.491 (relating to general requirements); and 34 Pa. Code § 39.496 (relating to stringing wires).