The four shock factors   Electrical hazards   Power safety quiz   Beware of power lines!   Pool safety   Construction sites   Info-Excavation   Power safety games		Beware of power lines! An overhead line is always a dangerous thing, but to fully understand the danger involved, you have to know something about the power distribution system. The only way to avoid an accident is to always stay at least 3 metres away from power lines. Telecommunication lines Closest to the ground are the telephone lines and television cables. They are the least dangerous of all, since they are very low-voltage. Low-voltage power lines Low-voltage power lines run below the transformers. They carry electricity to houses and buildings. Generally speaking, the wires are insulated and carry electricity at 120/240 volts or 347/600 volts. Despite what people may think, however, accidents involving 120-volt shocks can be fatal. Medium-voltage lines Medium-voltage lines carry electricity at 25,000 volts and directly supply large consumers like Montréal's subway system and certain industries. They also supply residential and commercial customers via step-down transformers. They are the small, bare wires you see at the top of power poles along highways and streets, and in alleys and backyards. These bare conductors are very dangerous-70% of accidents involving medium-voltage lines end in amputations. High-voltage lines High-voltage lines carry electricity from the generating stations where power is produced to populated areas at 44,000 to 735,000 volts. They are generally installed on towers. Only Hydro-Québec line workers are allowed to go near them. Transformer substations Transformer substations house high-voltage equipment, which is why they are surrounded by a fence. Signs warn passers-by of the danger and indicate that access is prohibited.