UL 1434 PDF

1 Scope

1.1 These requirements apply to discrete thermistor-type devices constructed of ceramic or polymeric semiconductor material.

1.2 These thermistors are intended for use as:

1. a) Self-limiting devices such as heaters;

2. b) Control devices such as current limiters and inrush-current limiters; or

3. c) Sensing devices.

1.3 These requirements apply to positive temperature coefficient (PTC) and negative temperature coefficient (NTC) type devices.

1.4 Control devices, such as current limiters are not intended to replace current interrupting devices such as fuses, but are intended to provide a level of overcurrent protection complying with the end-use equipment requirements.

1.5 These requirements do not apply to heating cables, such as self-regulating pipe heating cable, that are constructed with thermistor-type material.

1.6 Deleted

Summary of Topics

The revisions of UL 1434 dated May 18, 2021 include the following changes in requirements:

– Matching Table 11.3 and Table 22.1 to IEC 60730-1 Table J.7.

– For a sensing thermistor, corrections to use the same temperature terminology in the document; 12.2, 14.4, 15.1, 17.2