Motorized equipment also produces strong magnetic fields. However, short-term exposure to strong fields while shaving or drying one's hair is not likely to be a problem. Occasionally a nearby power line will produce this type of field. More often, it is caused by household plumbing carrying current. This situation is more likely to occur when the cold water pipe enters the opposite side of the building from the power line connection.
Safety codes require that the indoor plumbing be connected to the neutral wire of the power line.
This can result in current flow. In some older homes the hot and neutral power wires are not bundled closely together, but form a large loop with a gap between them. This creates a magnetic field that exists only when certain appliances are on, even if those appliances themselves are low-field. This can usually be corrected by using an extension cord to change to a different wall outlet, so that the current is carried through a different part of the in-wall wiring. Non-localized fields due to household wiring are usually highest in the room next to where the power line connects or where there is a circuit breaker box.