Firefighter hazard: Downed power lines
Understand the real risks electricity pose as you will likely encounter downed power lines when responding to structure fires, vehicle accidents or weather events
Electricity does not discriminate against anyone – and it kills. Downed power lines are a common hazard found at many vehicle accidents, structure fires or the after affects of bad weather. No matter where you are responding to in your department, you will encounter this hazard eventually.
The hidden danger in downed power lines is the electricity itself – we cannot visibly see it. We can see the effects of it (e.g., sparking or arching), but a downed power line or a hanging power line does not reveal its current. What we do see is the actual power line lying on the ground – this is the warning signal.
Wait for the power company to de-energize the lines
Whenever we do have downed power lines, we are taught that we must first de-energize the source in order to render the scene safe. This will be done by the utility or power company as they are the experts in this matter and they also own the line. Until that time, we are limited to what we can do.
In our corresponding video, we can see a situation where we have downed power lines causing further damage and making the scene worse. The video shot shows the responding crews standing back and observing what is happening while the fire rages on. To the general public, they may certainly be asking why, or complaining that the fire department is doing nothing to assist – but this far from the truth. According to the news reports, it took about 40 minutes to de-energize the power lines so that the crews could approach the scene and do their job in this instance.
The fire department on this call did an excellent job – but what would have happened if they did not wait for the power company? You can rest assured that we would be reading about a LODD involving one or more firefighters. It just takes one fraction of a second for a live power line to kill a firefighter. Add the component of water and other conductors that may be present, and it will affect all those in contact.
There are some who will believe that using a fog stream on the fire will decrease the chance of conduction from the live power source, but this is a bad train of thought. Water and electricity do not mix, no matter what type of stream you are using. We need to keep our distance back from the live power source, ensure that the public is also kept well away from the scene and wait until the experts arrive to de-energize the source.
Sometimes power grids are fed from two directions and when there is a fault interruption from the one end, it will re-boot with power from the other direction. So even if you think that the power has been terminated or shut off, it may not be, and you will be feeling the effects of it.