COS 2019-08-30T03:50:46+00:00



Attached to primary side of main equipment such as pillar transformer and mold transformer in order to protect them from over current due to short circuiting.

◆ Is completely compatible with products from other global businesses
◆ Led the technological and quality standardisation both domestically and internationally
◆ First polymer COS to be developed in Korea

  • Has a simple structure and high mechanical strength, as well as being easy to operate.
  • Has excellent electric and mechanical properties – proven by the fact that it led standardization both domestically and internationally.
  • Is the most exported product to the most number of countries.
  • Is light and easy to handle, which enable reduction of cost of construction and transport (polymer COS)
  • Has high tensile strength has polymer and FRP ROD has been used. Is also highly resistant to shock (polymer COS)
  • Is excellent in regions such as islands, cities, shores or factories where contamination-resistance is needed. ((heavy duty and polymer COS)


1995 November First magnetic heavy duty COS in Korea (25.8kV, 100A, 12kA, 150BIL)
1996 Magnetic heavy duty COS developed by Joongwon selected as the standard product by Korea Electric Power Corporation
1997 Magnetic COS selected as stanard product when developing KS standard (KSC4526)
1999 Standard magnetic COS by Joongwon selected as the standard product by Korea Electric Power Corporation (27kV, 100A, 10kA, 125BIL)
2000 Developed Korea’s first 12kA standard magnetic COS (27kV, 100A, 12kA, 125BIL)
2001 Developed Korea’s first polymer COS according to Korea Electric Power Corporation’s polymer COS standards (27kV, 100A, 12kA, 150BIL)


Catalog No. 80445 80445-P 80445-H 80442-H 80442 80443
Rated Voltage 34.5 25.8 25.8 25.8 25.8 14.4
Rated current 100 100 100 100 100 100
Maximum voltage 36 27 27 27 27 15
BIL(kV) 170 150 150 125 125 95
Leakage(Inches) 26 26 26 11 11 8.5
Breaking current(kA) Asym 12 12 12 10 12 16
Breaking current Sym 8 8 8 7.1 8 10.6
Insulator Magnetic Polymer Magnetic Magnetic Magnetic Magnetic
‧ Magnetic COS standard – ES 151-095~099 (Magnetic COS Korea Electric Power Corporation Standard),
‧ Polymer COS standard – Polymer COS Korea Electric Power Corporation Standard, ANSI/IEEE C37.41/42, IEC 60587/60707/61109, IEEE Std 1024, ASTM G53

※ Warning
Considering the electric/mechanical characteristics of COS, it is best to use a fuse link that is manufactured by the same company.