Why hydro poles could be more susceptible to catching fire in winter

January 2018

We’re often asked how is it possible that hydro poles in the middle of winter can catch fire? It’s a good question, and it involves circumstances that Burlington Hydro, along with many other electricity utilities, experience during the winter season.

In recent years, the use of salt brine has become a more common treatment on road applications ahead of anticipated snowfalls.  The resulting spray created by these applications produces a contaminate mist that rises and then accumulates on hydro poles, particularly in the vicinity of high traffic roads and highways. The salty brine mix adheres, building up on utility poles, insulators and line equipment.

On days when we experience a winter thaw, the highly-conductive brine creates the conditions for electricity to travel from the line to the insulator, and the metal bolt attached to that equipment. The heat builds up and can char and set the pole on fire. This often results in severely damaged or broken poles that first need to be extinguished by the fire department before repairs by hydro crews can safely begin.

Over extended cold snaps, this brine mixture can build up within encrusted ice on the poles and equipment, heightening the potential for problems should a sudden thaw occur. Similar conditions also exist in humid and foggy conditions, and with freezing rain.

Every attempt is made to isolate the damage and bring customers back on-line as quickly and as safely as possible. The duration of the outage depends on the severity of the damage to equipment and power lines and the time it takes to safely restore power to affected customers.

Burlington Hydro is aware of the increased potential for pole fires under these circumstances. Although we cannot be protected completely by these occurrences, there are steps that are being taken to mitigate the risk. As soon as temperatures stabilize above freezing, crews are assigned to washing details to remove salt brine from insulators in highly travelled corridors. Second treatments are applied in susceptible areas where insulators experience a higher incidence of pole fires. These steps are now taken as part of Burlington Hydro’s regular maintenance regime.