The seismic capacity for the equipment class of transformers (TRN) maybe based on earthquake experience data. This equipment class includes the unit substation type, typically 4160/480 volts, and the distribution type, typically 480/120 volts.
Office of Environment, Health, Safety & Security
October 21, 2026
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The seismic capacity for the equipment class of transformers (TRN) maybe based on earthquake experience data. This equipment class includes the unit substation type, typically 4160/480 volts, and the distribution type, typically 480/120 volts. Main power transformers with primary voltages greater than about 13,800 volts are not included in this equipment class. Small transformers that are components of electrical equipment, such as motor control centers or control panels, are also not included in this equipment class but are addressed as components of other classes of electrical equipment.