These requirements cover Class T fuses for use in accordance with the
National Electrical Code,
A Class T fuse has a maximum current rating of 1200 amperes, and a
voltage rating of 300 volts a-c
to ground and a maximum current rating of 800 amperes and a voltage
rating of 600 volts a-c.
Class T fuses are of the nonrenewable cartridge current limiting type
and have an interrupting
rating of 200,000 amperes rms symmetrical, with peak let-through
currents and total clearing
amperes-squared-seconds specified for the individual case sizes.
These fuses are intended for use with fuseholders that will properly
receive Class T fuses, but
will not receive fuses of any other type. The 300 volts knife
blade-type fuses rated not more than
600 amperes are for either clip mounting or bolted-in installation.
The 300 volt fuses rated more
than 600 amperes and the 600 volt knife blade fuses are for bolted-in
A product that contains features, characteristics, conponents, materials, or systems new or different from those in use when the standard was developed, and that involves a risk of fire, electric shock, or injury to persons shall be evaluated using the apprropiate additional component and end-product requirements as determined necessary to maintain the level of safety for the user of the product as originally anticipated by the intent of this standard.