17.2 Protective devices for power transformers
[Basic requirements]
Power transformers that have a rated output of 15 VA or higher shall incorporate protective devices, in order to prevent smoke emission, ignition, fire and electric shock hazards.
[Design standards]
1) Such transformers shall contain a thermal fuse or be provided with an overheating protection device.
2) A protective device may not be required if the winding temperature, upon short circuit of the secondary winding, does not exceed the values given in the table below.
3) Industrial equipment and FA equipment, which comply with the requirements in Article 1.2, shall be considered to be in conformity with this requirement.
[Criteria]
1) Compliance is determined by visual inspection.
2) Compliance is determined by conducting the temperature rise test.
3) Compliance is determined on the basis of Article 1.2.