A better DC hot stick technology is on the way

New tool will help prevent first responder electrical injury

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electric car and solar panels

A hot stick is a tool (or probe) that first responders have used for years to prevent on-scene electrical injuries. It detects the presence of Alternating Current (AC) voltage in a wire or conductive material. A typical AC hot stick doesn’t work, however, for Direct Current (DC) voltage due to significant differences in the physics involved.

A new tool for DC voltage hazards

DC voltage is now found in a growing number of today’s technologies that first responders encounter, such as:

  • Solar photovoltaic system installations.
  • Electric vehicles.
  • Fuel cells, power storage arrays and super capacitors.
  • Mass transit applications.

These hazards require new tools to keep first responders safe from electrical exposures. That’s why the USFA is working with Oak Ridge National Laboratories to develop a better DC hot stick technology. DC detectors exist today but are so bulky and unreliable that they are unsuitable for field use.

DC and AC hotsticks The prototype DC hot stick (top) is shown with a commercially available AC hot stick.
DC hot stick grounding clamp Grounding clamp with positive confirmation of contact.

The USFA/Oak Ridge hot stick prototype is similar in appearance to most existing AC probes and familiar to first responders. It’s designed to slip onto the end of an AC probe. The prototype not only detects DC voltage, but it also ensures that the probe is properly tapped into the electrical lines being tested. This prevents false negatives. A green light indicates proper contact, and if voltage is detected, a red light is illuminated.

DC hot stick inside an electric vehicle DC hot stick voltage probe inside a hybrid electric vehicle with voltage readout.

A patent for the prototype has been licensed and product testing is underway. We anticipate that a new product will be announced to the market soon.

Learn more about this research

For more information, please contact the USFA’s Larry McKenna at 301-447-1361.

DC hot stick technology is just one of the many accomplishments of the USFA's National Fire Programs (NFP) Division in 2018. For more information, download NFP 2018 Highlights PDF 188 KB.

This summary is for informational purposes only. More +
As such, the content does not reflect any official positions, policies, or guidelines on behalf of the sender, the U.S. Fire Administration, FEMA, DHS, nor any other federal agencies, departments or contracting entities. Similarly, this summary does not represent in any manner an official endorsement or relationship to any private or public companies, organizations/associations, or any authors or individuals cited or websites associated within the article.

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