STANDARDS AND RATINGS - BUSHINGS

Porcelain Equivalent Epoxy Bushing for Indoor & Outdoor Applications

Current Ratings Voltage Ratings Polycast type tests the bushings it supplies, and will assist its customers in determining optimum conductor sizes and arrangements for their applications. However, it is not practical to pre-determine the absolute maximum current ratings for every bushing and for every possible bushing variation, or every condition of use. Thus, we specify a conservative nominal current rating or, where experience allows a practical current rangefor each bushing replacement, based upon: Type tests Test data from equivalent units Industry standards Because the conditions of use of any bushing is beyond our control, it is always the responsibility of users to ensure that the current carrying capability of any bushing they use is not exceeded in their application. Polycast Standard Ratings Transformer Bushings Switchgear Bushings Nom. Voltage Class kV Low Freq Dry kV Impulse (BIL) kV Crest 1.2x 50us Chopped Wave kV Crest ( us) Nom. Voltage Class kV Low Freq. Dry kV Impulse (BIL) kV Crest 1.2x50us 0.6 0.6 4 10         01 1.2 2 10 30 36 (1.0)       02 2.5 2 15 45 54 (1.5)       05 5.0 2 21 60 69 (1.5) 4.76 19 60 08 8.7 2 30 75 88 (1.6) 8.25 26 75 15 15.0 2 35 95 110 (1.8) 15.0 36 95 18 15.0 P 50 110 126 (3.0) 15.5 50 110 25 18.0 2 42 125 145 (2.25) 25.8 60 125 28 25.0 P 60 150 175 (3.0) 38.0 80 150 35 36 IEC 70 170 195 (3.0)         38 34.5 P 80 200 230 (3.0) 38.0 80 200 46 46.0 P 105 250 290 (3.0)       2 ANSI / IEEE C57.12.00 = Distribution Transformers PANSI / IEEE C57.19.01 = Outdoor Power Transformers IEC IEC 137 ANSI / IEEE C37.20.2 & 3

Conductor Material: Electrolytic copper is standard in all Polycast bushings. Cast copper, aluminum or forged aluminum options are also available for some items. Plating: Tin plating is standard for all transformer bushings, silver is optional Silver plating is standard for all switchgear bushings, tin is optional. Ambient Working Temperatures: Indoor Bushings:          Ambient -40C to +55C Outdoor Bushings:       Ambient -50C to +55C Transformer Bushings: Oil Temperatures to 100C These ambient temperatures are considered safe for all bushing applications. The various epoxy systems used by Polycast in bushing design have continuous operating temperature capabilities ranging from 120C to 180C, and all of these systems are capable of even higher temperature withstands on an intermittent basis. Please consult catalog pages for recommended maximum continuous operating temperatures or contact Polycast for any special requirements. Technical Standards: Polycast designs and manufactures a wide range of bushings for transformer, switchgear and other power applications to meet North American and International Standards. IEC 137 is used as a technical guideline, but ANSI and CSA specifications for specific types of bushings are always considered.