How far away from 500 kV power lines can potentially dangerous currents be induced into metal structures?
Residential properties directly adjacent to an existing 500 kV transmission line (i.e., with their back fences about 25 metres from the transmission line) have experienced nuisance induction onto ungrounded objects such as eaves troughs, metal sheds, and metal fences. These shocks can be prevented by grounding the structures. AltaLink or EPCOR will install appropriate grounding on metallic objects which experience nuisance induction from our facilities. Homes that are a little further away or have shielding from a 500 kV transmission line, such as trees, do not generally experience these types of induction effects. Clearance and set-back requirements in place for overhead lines are designed to ensure that objects in close proximity will not experience flashover or dangerous induction effects. These clearance requirements are not designed to completely eliminate nuisance induction effects.
