1 Scope

1.1 These requirements cover enclosed and open-type Surge Protective Devices (SPDs) designed for repeated limiting of transient voltage surges as specified in the standard on 50 or 60 Hz power circuits not exceeding 1000 V and for PV applications up to 1500 V dc and designated as follows:

1. Type 1 – One port, permanently connected SPDs, except for watt-hour meter socket enclosures, intended for installation between the secondary of the service transformer and the line side of the service equipment overcurrent device, as well as the load side, including watt-hour meter socket enclosures and Molded Case SPDs intended to be installed without an external overcurrent protective device. Type 1 SPDs for use in PV systems can be connected between the PV array and the main service disconnect.

2. Type 2 – Permanently connected SPDs intended for installation on the load side of the service equipment overcurrent device; including SPDs located at the branch panel and Molded Case SPDs.

3. Type 3 – Point of utilization SPDs, installed at a minimum conductor length of 10 meters (30 feet) from the electrical service panel to the point of utilization, for example cord connected, direct plug-in, receptacle type and SPDs installed at the utilization equipment being protected. See marking in 4. The distance (10 meters) is exclusive of conductors provided with or used to attach SPDs.

4. Type 4 Component Assemblies – Component assembly consisting of one or more Type 5 components together with a disconnect (integral or external) or a means of complying with the limited current tests in 4.

5. Type 1, 2, 3 Component Assemblies – Consists of a Type 4 component assembly with internal or external short circuit protection.

6. Type 5 – Discrete component surge suppressors, such as MOVs that may be mounted on a PWB, connected by its leads or provided within an enclosure with mounting means and wiring terminations.

Summary of Topics

This revision of ANSI/UL 1449 dated October 21, 2025 includes the following changes in requirements:

– Addition of Requirement for Type 5 SPDs, Discrete Components Used in Damp Locations; 3.9A, Section 42A, Section 78A, and 85.43.

– Correction to Table 37.1.

– Addition of UL 508 Requirements for a DC Power Source; SB5.1.

– Clarification of UL 1449 SCCR and Intermediate Current Testing Duration; 45.2 (title), 45.2.3, 45.3.1, and 45.3.2.

– Addition to Section 43 – Surge Testing.

– SPDs with Obstructed Capped/Plugged Terminals; Section 36A and Section 83A.

– Allowance for the Use of Quick Response Codes (e.g. QR Codes); 86.1 and 86.6.

– Updates to Table 37.2.

– Types 1, 2 and 3 Enclosed SPDs Incorporating Aluminum Rivets; 17.1.5 and 17.1.11.