3.2 Instrument Transformers. To have meters function effectively within their
capabilities, current transformers and potential transformers are used.
Intended for measurement and control purposes, they perform two primary
line current or voltage to values suitable for standard
instruments which normally operate on 5 amperes and 120 volts.
instruments and meters from line voltage. To u ake this
protection complete for both instruments and operators, THE SECONDARY
CIRCUIT SHOULD BE GROUNDED. For grounding , see IEEE Standard 52,
Application Guide for Grounding of Instrument Transformer Secondary
Circuits and Cases.
NEVER SHORT A POTENTIAL TRANSFORMER SECONDARY WINDING.
NEVER OPEN A CURRENT TRANSFORMER SECONDARY WINDING.