ELECTRICAL SAFETY DESIGN

Wiring Design and Protection - Support, Enclosure, and Equipment Grounding

If exposed non-current carrying metal parts of fixed equipment operates with any terminal at over 150 volts to ground which may become energized it must be grounded. However, there are exceptions to this situation. These exceptions are:

Enclosures for switches or circuit breakers used for other than service equipment and only accessible by qualified person

Metal frames of electrically heated appliances which are permanently and effectively insulated from ground

The cases of distribution apparatus such as transformers and capacitors mounted on wooden poles at a height exceeding 8 feet above ground or grade level.

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