T&D World Magazine
Contact Voltage Testing Services for Utilities

Contact Voltage Testing Services for Utilities

Field technicians no longer have to worry about influences from overhead distribution/transmission line electric fields.

Utility Testing and Geographic Information Systems has launched Advanced Contact Voltage Testing services after developing a new line of electrical safety testing instruments. These instruments represent the first new innovation in the contact voltage services field in almost a decade and permit the first major revision to the 10 year old testing protocols.

"Contact voltage is the presence of an electric potential on publicly accessible objects that should not normally be energized" according to UTGIS President Mark Voigtsberger "Typically these objects are the exterior structure of light poles- but have also include traffic signals, junction boxes or other similar conductive surfaces." Contact voltages can present a shock or electrocution hazard to humans and companion animals under the right circumstances and if the levels are high enough.

"One of the fundamental problems with all existing contact voltage survey testing devices is that they cannot detect lower voltage levels reliably and consistently.  This is a major shortcoming because the data indicates over 50% of all contact voltages are less than 5 volts (Vac)." said Voigtsberger.

While contact voltages less than 5 Vac are not a human safety issue, some states require the documentation of 1 Vac and above. To resolve existing equipment shortcomings, UTGIS developed the first calibrated direct reading testing instruments specifically intended to accurately measure 0.01 Vac and higher to comply with those utilities and municipalities needing documentation down to 1 V. 

Existing contact voltage testing instruments are qualitative in operation and extremely prone to errors. The UTGIS equipment line uses a proprietary quantitative method to determine if contact voltages are present- and displays that value in real time.

The UTGIS Advanced Contact Voltage Testing equipment also addresses a second significant problem inherent with the existing process: eliminating a complex multi-step procedure to determine if contact voltage is actually present on an object.  The new UTGIS testing method requires only one step to record the true and accurate contact voltage on the item under test.  Field technicians no longer have to worry about influences from overhead distribution/transmission line electric fields, driving ground rods, installing shunt resistors or stringing long test leads as the existing protocol dictates.

Advanced Contact Voltage Testing permits the "spread" mapping of an electrical voltage gradient.  Almost 40% of reported contact voltages under the present testing system are false because existing test equipment cannot map the voltage gradient.  The UTGIS equipment permits technicians to pinpoint and segregate the actual source of the contact voltage from ancillary objects.  Ancillary objects such as fire hydrants, traffic signs, water and gas valve covers, are surfaces that may have an electrical potential on them not because they are actually energized, but are energized because they fall under the voltage spread of the source object.

 

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