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Benefits of the Optima

  • Improved Isolator Disconnector Reliability
  • Patented Isolator Design Good Down to One Amp Operation
  • Saves Utilities Money and Improves System Reliability
  • Higher 60 Hz TOV Capability
  • Field Proven Sealing System

Basic Construction

In Optima arresters, the Varistors are locked in place with tightly wound layers of fiberglass filament impregnated with epoxy resin. The arrester housing is made from our proprietary blend of ESP silicone alloy. In addition to ESP's exceptional performance as an insulator material, ESP's properties have been confirmed in a series of performance tests which include tracking resistance, contamination, aging, and seal design.

Optima arresters can be used with all standard mounting arms and brackets. They come with all the necessary fasteners, isolators, and terminal attachments. A specially designed glass-filled polyester insulating bracket, with integrated disconnector, along with optional mounting brackets such as the cross arm or transformer bracket, enable mounting the arrester in a way which best suits each individual customer. Below is a typical cross section view of one of our distribution type arresters.

Selection Considerations

Selection of arrester size is based upon the maximum continuous operating voltage (MCOV) that is applied across the arrester in service (line-to-ground). For arresters on effectively grounded systems, this is normally the maximum line-to-ground voltage - e.g., 7.65 kV on a 12.47 kV multi-grounded system. For ungrounded or impedance-grounded systems, the MCOV should be at least 90 percent of maximum phase-to-phase voltage. Smaller arresters than shown may be used, contact your Ohio Brass representative for details.

For convenience, the data shown in this catalog includes the traditional duty-cycle voltage rating associated with the MCOV of each arrester.

The selection of the actual type will be primarily governed by the insulation being protected.

System L-L
Voltage kV
Arrester MCOV-kV
Nominal Maximum Effectively Grounded (Wye)
Neutral Circuits
Impedance Grounded,
Ungrounded, or Delta Circuits
2.4 2.54 - 2.55
4.16 4.4 2.55 5.1
4.8 5.08 - 5.1
6.9 7.26 - 7.65
12.0 12.7 7.65 12.7
12.47 13.2 7.65 -
13.2 13.97 8.4 -
13.8 14.52 8.4 15.3
20.78 22.0 12.7 22.0
22.86 24.2 15.3 22.0
23.0 24.34 - 22.0
24.94 26.4 15.3 -
34.5 36.5 22.0 29.0
Hubbell Power Systems All contents Copyright© 2001 - Hubbell Incorporated. All rights reserved. Because Hubbell has a policy of continuous product improvement, we reserve the right to change design specifications without notice.
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