Final installation of AR Switch in 36kV line with 12.47kV underbuilt circuit.

Lineman Bill Schmahl operates switch with a hook stick. Easy opening and closing by hook stick control (below) is due to the lowest torque requirement in the industry for the AR Switch overtoggle operating mechanism.

Daron Beesley and Lewie O’Harra of Idaho Power Company’s Methods and Materials group are pleased with their choice of options on the newest type of Hubbell unitized hot-stick-operated pole top switch.

The AR (Automation-Ready) Switch not only gives them the sectionalizing capabilities needed, but also affords practical control features to solve challenges posed by the locations and system situations.

Public access concerns
A traditional pole top switch has an operating handle mounted near the ground and is connected to the switch by a control rod. Although this configuration is convenient for the lineman, the handle is also accessible to the public which increases exposure to accidental contact and the possibility of tampering. The first two AR Switches for Idaho Power were installed in rural agricultural settings where farm equipment could come into contact with the switch control handles.

System operation concerns
Because the 35kV line shared poles with an underbuilt 12.5kV line, a traditional pole top switch would require the operating controls to pass through the lower circuit. While not uncommon, that arrangement was not preferred.
Another issue is that Idaho Power construction specifications, and those of many other utilities, require a labor intensive ground grid to be installed at the base of a pole with a traditional type switch.

AR option delivers all solutions
By design, a single AR Switch option was available to fill all of these needs for Idaho Power. The unique optional hook stick control furnished an elegant solution for this set of application challenges. It replaced the traditional control rod and handle that could have been inadverently damaged by passing equipment or operated by unauthorized personnel. It avoided any need for extra clearance from the underbuild.

The AR – a switch for all the right reasons
Another benefit was faster installation because no adjustments to the control mechanism were needed, no ground grid was installed, and only two holes were drilled in the pole because no crossarm braces were required. Although Idaho Power selected an AR Switch to meet the needs of these specific applications, AR Switches also have standard features that meet all of their unitized three-phase distribution-switch requirements:

• Excellent sectionalizing (900-Amp interrupt rating)
• Exceptional ice-breaking (industry record 3?4"-ice open-and-close capability)
• Easy operation (industry’s lowest torque requirement to open and close a switch of this kind).