These Requirements cover air-cooled transformers and reactors for general use and for use with mercury-vapor lamps, sun lamps, etc.; transformers for use with Class 2 remote-control, low-energy-power, and signal circuits; ignition transformers for use with gas burners and .oil burners; gas-tube-sign transformers for use with inert-gas tubes; and toy transformers; to be employed in accordance with the National Electrical Code.
These Requirements do not cover oil-filled transformers, special types of transformers covered in Requirements for other electrical devices or appliances, autotransformers forming parts of industrial control equipment, nor transformers having a primary rating of more than 600 volts.
These Requirements are based upon records of tests and field experience and are subject to revision as further experience and investigation may show to be necessary or desirable.
A product which complies with these Requirements will not necessarily be acceptable if, when examined and tested, it is found to have other features which impair the result contemplated by these Requirements.
A product employing materials or having forms of construction differing from those detailed in these Requirements may be examined and tested according to the intent of the Requirements, and if found to be substantially equivalent may be given recognition.
Requirements are shown in bold-faced type and are supplemented by explanatory notes and descriptions of test apparatus and methods in light-faced type.