Essential services. Nothing in this chapter shall preclude the construction,
operation and maintenance of public utility, transmission, distribution
or collection systems in any zone for water, gas, telephone, or electric
service subject to the conditions of this chapter. Such systems may
include systems of poles, wires, underground pipes, conduits, ducts
and transformation equipment, including substations and appurtenances,
necessary for the transmission and/or distribution of the commodity
or service rendered by the public utility to its customers.