The wires were live, carrying 600 volts of electricity, when the unidentified victim came into contact with them, although it is not clear whether the wires fell onto her, or whether she rode into them.
Emergency responders treated the woman before she was sent to hospital with unknown injuries. She is believed to have been conscious when transported to hospital.
Gabe Roder with the Vancouver Fire Service couldn't confirm whether she was shocked by the wire, but said the accident could have been a lot worse.
"One of the things we do want to stress to the public is that anytime they do see live wires, particularly trolley wires, those wires have 600 volts of energy in them," said Roder.
"They do have a potential to cause a lot of harm, injury and even death, so if you see them down please keep away from them."
Roder said they respond frequently to trolley wires down, but not as often to electrical shocks caused by the wires.
"Although I do have to stress...it's alarming, when these wires are down, how many people do walk very, very closely to them, not realizing that the potential that these have to cause a tremendous amount of harm."
Some 300 trolley buses course through Vancouver every day. TransLink is investigating the incident but estimates wires come down an average of once per month.
Friday's accident comes only a week after a , when a crane came into contact with an overhead power line.