Homeowners should rely on experts like electrician Dave Giles. CBC

N.B. Power is warning its crews face potentially fatal shocks because homeowners using generators are accidentally firing up power lines.

Crews cleaning up after tropical storm Irene have found two power lines that were unexpectedly live due to private actions.

Tony O'Hara, executive director of transmission for N.B. Power, said that could have lethal consequences. It is safe to plug individual appliances into a home generator, but not to connect an entire house to one. Doing so could massively boost levels of electricity.

"I do want to emphasize for the homeowner if that's not installed correctly, there are definitely shock and fire hazards within the house as well,” he said.

"In this case, it goes from 120 volts and actually steps it up to 7,200 volts onto the distribution system. It in effect energizes a section of the distribution system."

Hire an expert for safe work

Experts say homeowners need to hire a professional electrician to hook up a generator so the current doesn't run back out to the power pole.

Electrician Dave Giles said even a small charge from a generator can get boosted by the main power line.

"The proper way to do it to the Canadian Electrical Code is to have a proper transfer switch panel, which simply means that you have to be able to isolate your generator source and your main power source,” he said.

“If there's a problem out on the line, your generator is not going to back-feed out and cause N.B. Power grief."

Meanwhile, power is back on for the whole province a few days after the storm knocked out electricity to more than 50,000 customers.