Contact voltage incidents usually caused by aging equipment:utility


SAINT JOHN, N.B. — Although officials say the conditions that caused a brief electrical shock to a man and his dog in Saint John, N.B., earlier this week are rare, at least one major city has spent millions of dollars addressing similar problems largely caused by aging infrastructure.

Saint John Energy said heat damage to some insulation combined with wet and salty conditions on Monday is believed to have caused electrical tracking that reached an above ground metal plate cover or handwell in the city’s uptown area.

A man who was walking his dog near the electrical equipment on Prince William Street was briefly shocked, as was the dog, after touching the metal cover.

Saint John deputy fire chief Joe Armstrong said the man was checked over in a hospital and released, while the dog didn’t appear to be seriously hurt.

In an email Wednesday the city’s utility confirmed the problem was caused by a combination of older equipment and weather conditions.

"Saint John Energy wants to ensure the public that this is an extremely rare event and will remain diligent in our efforts to ensure that our entire electrical infrastructure is inspected and maintained at or above industry standard," Saint John Energy said in a statement.

The problem, known in the industry as contact voltage, has been a priority in cities such as Toronto in the past few years.

"You are going to see it where there’s aging infrastructure," Toronto Hydro spokeswoman Tori Gass said in an interview Thursday.

"There are wires that are degraded underground and that can be from a number of things," she said. "It’s usually worse in winter where there is salt and slush on the road."

Gass said the utility embarked on a replacement program for handwells after a series of incidents over a few months in 2009. She said in two of the incidents dogs died after being electrocuted.

"Since 2009 for everything we’ve spent approximately $100 million remediating our contact voltage issue," she said.

Gass said the work has involved replacing metal handwells with non-conductive concrete polymer coverings and upgrading wiring connectors near street lights to better protect them from corrosion.

Toronto Hydro also uses trucks five nights a week that are equipped with instruments to scan the streets for any potential contact voltage problems.

"We’ve only had one incident that we are aware of this year involving a dog and it wasn’t serious, so that’s telling us that our program has worked," said Gass.

Gass estimates about 1,000 of the city’s 12,000 handwells still need to be replaced as part of the utility’s ongoing work.

31/12/2015 14:02  By: Metro News