17.1 Overload protection of equipment that uses a power transformer
[Basic requirements]
The primary circuit of equipment that uses a power transformer with a rated input of 15 VA or higher
shall be equipped with a protective device, in order to prevent smoke emission, ignition and fire
hazards.
[Design standards]
1) The primary circuit shall be provided with a current-limiting fuse or an equivalent protective
device.
Note: Equipment having multiple transformers needs not have a protective device for each
transformer, if the equipment can be protected even when some transformers are
damaged.
2) A welding machine is considered to comply with this requirement, if it is clearly indicated in the
wiring instruction manual or in the operating instruction manual that the prescribed
current-limiting fuse shall be used in the switch box.
[Criteria]
1) Compliance is determined on the basis of the circuit diagram and by visual inspection.
2) Compliance is determined on the basis of the wiring instruction manual or the operating
instruction manual.