Solid-state overcurrent protectors on the secondary side of a power supply or battery (UL Recognized).
The standard covers solid-state overcurrent protectors: electronic switching devices that limit output current to a safe level when the current-limiting threshold is exceeded or when a short circuit occurs on the load side. The products operate on the secondary side of an isolating transformer, power supply or battery as supplementary protection for low-power secondary circuits (rated overcurrent protection up to 5 A, output voltages in the range of 20–60 V AC or 20–30 V DC). They are entirely electronic, with no mechanical action or manual reset, and have terminals intended for factory wiring on printed circuit boards.
The standard does not cover branch-circuit protection or primary circuits.
UL 2367 certification (UL Recognized Component) allows an electronic current limiter to be used as supplementary protection in equipment secondary circuits (for example, 24 V DC power-supply outputs or power distribution in a control cabinet) without evaluating it as a circuit breaker.
The product is not evaluated for branch-circuit protection (UL 489) and differs from UL 1077 because it has no mechanical part and is limited to low voltage and low power on the secondary side. There is no EU standard with the same scope; assessment is performed under the standards applicable to the end equipment.
The standard evaluates the ability to limit output current under overload and load-side short-circuit conditions to a value below the rated overcurrent-protection level. The product scope is defined by Table 1.1: no-load output voltage, allowable short-circuit current and output power.
Products covered by the standard are integrated circuits, so the standard does not specify internal insulation spacings (Clause 1.2); they operate entirely electronically, without a mechanism or manual reset (Clause 1.3), and their terminals are intended only for factory wiring, with printed-circuit-board mounting (Clause 1.4).
Clause 1.5 also covers products serving as current limiters for limited-power sources under UL 62368-1 and UL 60950-1. Approval is granted as a UL Recognized Component, with Conditions of Acceptability evaluated in the end equipment.
For a 24 V DC electronic protection device, check whether the declaration states UL 2367 Recognized (supplementary protection on the secondary side), the UL file number, the certified output voltage and current, and whether the power supply primary circuit has separate branch-circuit protection.
