Plug fuses of the Edison-base type shall be used only for replacement in existing installations where there is  no evidence of overfusing or tampering.

Fuese, fuseholders and adapters must be so designed that other type S fuses may not be used.

It is a dual element fuse with special threads so that fuses larger than what the circuit was designed for may not be used. They are designed to make tampering or bridging difficult.

In a vertical position, so that when the switch is opened, the blades will not close by gravity; the line side must be connected so that when the switch is opened, the fuses will be de-energized.

There must be no fusing in the high side, or primary; since the booster transformer is similar to a current transformer, if the fuse should blow, an extremely high voltage could be built up on the secondary side.

A thermal fuser protects the fuser assembly from overheating and damaging the printer.

One of the main uses of the resistance function is to test fuses. You must disconnect at least one end of the fuse from the system. You should set the meter on the 1k-ohm resistance setting. If the fuse is good, the meter should read near 0 ohms. If it is bad, the meter reads infinite.