Is the secondary of a transformer considered to be a source of power for the purpose of E-11.12.2.9.1.2?
A. No, the transformer secondary is not considered a source a power. The committee stated that a circuit breaker is does not have to be located at the transformer as long as it is located somewhere between the transformer secondary and the load distribution panel. Q. If the secondary conductors in a 120/240 VAC transformer installation were sized to accommodate the level of current necessary to trip the primary circuit breaker, AND additional simultaneous trip circuit protection was provided in the secondary conductors at the main panel, in addition to branch circuit protection, would it be necessary to provide overcurrent protection in the secondary conductors within 7 inches (40 inches if in a sheath) of the transformer? (Does this scenario satisfy the intent of the section?) A. The committee felt that, as long as the secondary conductors were protected from overcurrent by the secondary breaker there is no opportunity to overload the transformer secondary due to an unbalanced 120/240
