scope:

This Recommendation sets terms, test methods, test circuits, measurement procedures and preferred result values for the surge parameters of isolating transformers used in telecommunication devices and equipment. Three types of isolating transformer are covered: mains, switched mode power supply and signal. The surge parameters of the isolating transformer insulation barrier covered by this Recommendation are:

• rated impulse voltage;

• input winding to output winding capacitance;

• insulation resistance.

Additional parameters for signal isolating transformers are:

• core saturation voltage-time product;

• rated input winding root mean square (rms) current for a given temperature rise.

This Recommendation does not cover the transformer parameters required to help ensure appropriate operation on the service, e.g., signal transformer return loss.