In Michigan, electrical elements of any residential building must follow the state electrical code, itself based on the National Electrical Code, or NEC. Several sections of the code apply specifically to residential buildings or relate generally to any kind of electrical work.
In chapter 1, the Michigan Electrical Code outlines general requirements for electrical installations. It prescribes using only approved devices and conductors and using only copper conductors, unless otherwise indicated. When mounting any elements, use solid means of securing and fastening; for example, do not drive wooden plugs into concrete, masonry, plaster or similar substances. In addition, provide open, airy spaces when installing any electrical devices that require ventilation to maintain their cool temperature. Any "live" parts, or elements that carry an electrical current, must not be exposed to human contact. You may shield these parts by enclosure within a dedicated and closed room, by partitions or by elevation at least eight feet above the floor.
Flexible Cords and Wiring
The Michigan Electrical Code outlines the voltage, insulation type and thickness, braiding material and intended usage of all kinds of flexible cords and wiring. Lamp cord must have a voltage of 300 to 600, two or more conductors, and thermoset or thermoplastic insulation, and it should serve for light to moderately-used purposes in dry locations. Thermoset-jacketed heater cords must serve up to 300 volts, have two to four conductors, bear thermoset or oil-resistant thermoset insulation and may be used in damp locations and exposed to hard usage. Hard service cord must accommodate up to 600 volts, use two conductors, have thermoset or oil-resistant thermoset insulation and serve for extra hard usage, in damp and wet locations.
Kitchens and Bathrooms
The Michigan Electrical Code requires that at least two 25 ampere circuits serve all outlets above kitchen countertops. They must also bear GFCI (ground fault circuit interruptor) protection. In bathrooms, at least one receptacle must be within three feet of a sink, mounted on the wall adjacent to the sink or the sink countertop. At least one wall switch-operated lighting fixture must be in every habitable room and in every bathroom. In addition, residences must feature one switch-operated light in any hallway, stairway, attic, underfloor storage space and any attached garage and electrified detached garage.
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