scope:

1.1 This standard covers solid-state overcurrent protectors. These devices are solid-state switches that limit the output current to a safe level when the output load exceeds the current-limit threshold or when a load-side short-circuit is present. Solid-state overcurrent protectors are intended to be used on the load-side of an isolating transformer, power supply or battery to provide a means of supplementary protection. See for maximum current and power levels.

Output voltage (V_oc)

Output current (I_sc)

V_ac

V_dc

A

(V × A)

≤ 20

≤ 20

≤ 1000 / V_oc

≤ 250

20 ≤ V_oc ≤ 30

20 ≤ V_oc ≤ 30

≤ 1000 / V_oc

≤ 250

-

30 ≤ V_oc ≤ 60

≤ 1000 / V_oc

≤ 250

1.2 The devices covered by these requirements are integrated circuits, and electrical spacings within the devices are not specified.

1.3 The devices covered by these requirements are entirely electronic in nature and have no means for mechanical operation or reset.

1.4 The terminals of the devices covered by these requirements are for factory wiring only (intended to be mounted on a printed wiring board).

1.5 This Standard also covers devices intended to be used as limited power source current limiters in accordance with UL 62368-1, Audio/Video, Information and Communication Technology Equipment - Part 1: Safety Requirements, and UL 60950-1, Information Technology Equipment - Safety - Part 1: General Requirements. These devices limit output currents to values less than the protective current rating of 5 amperes and a maximum output power of 100 VA.

1.6 The devices covered by these requirements limit output currents to values less than the overcurrent protection rating of 5 amperes.

1.7 The devices covered by these requirements have only been evaluated for supplementary overcurrent protection of secondary circuits supplied by the load side of a transformer, power supply or battery and have not been evaluated for branch-circuit protection.

1.8 This Standard may cover devices intended for use in telecommunications applications. However, devices intended for connection to telecommunications networks with outside plant connections should be evaluated in the end-use in accordance with the requirements of the Standard for Information Technology Equipment - Safety - Part 1: General Requirements, UL 60950-1, the Standard for Audio/Video, Information and Communication Technology Equipment - Part 1: Safety Requirements, UL 62368-1, or the Standard for Secondary Protectors for Communication Circuits, UL 497A, as appropriate.

1.9 This Standard also covers solid-state overcurrent protectors that are identified as providing Class 2 limitations as defined in the National Electrical Code, NFPA 70. See Section 10, Class 2 Limitations per NFPA 70, Article 725.