UL 2108 2023-04 PDF

Full title and description

UL 2108 — Standard for Low Voltage Lighting Systems (redline revision April 18, 2023 / referenced as 2023‑04). This document contains safety, construction, marking, and performance requirements for low‑voltage lighting systems and associated components intended for installation in accordance with the National Electrical Code (NFPA 70), Article 411.

Abstract

UL 2108 sets requirements for permanently installed low‑voltage lighting systems (including Class 2 systems, exposed bare conductor systems, POE and other low‑voltage luminaires) and for power units limited to specified outputs. It addresses electrical spacing, markings, mounting and supply connections, impact and drop tests, requirements that apply from UL 1598 and other UL luminaire standards where relevant, and references LED component requirements in UL 8750. The standard is maintained by Underwriters Laboratories and has been issued as Edition 2 with subsequent redline revisions, including the April 2023 redline.

General information

• Status: Active — maintained by Underwriters Laboratories (UL).
• Publication date: Edition 2 originally published December 7, 2015; redline revision April 18, 2023 (commonly referenced as 2023‑04). (Later revisions are available; users should check UL release history for the most recent redlines or revisions.)
• Publisher: Underwriters Laboratories (UL).
• ICS / categories: Electrical engineering — lighting systems / safety standards; applicable to low‑voltage lighting and related electrical equipment.
• Edition / version: Edition 2 (current main edition); April 2023 redline revision (redline documents show changes proposed/issued on that date).
• Number of pages: Full standard edition documents vary by release (the 2021/Edition‑2 distribution is commonly shown as ~76 pages for the full standard; redline/bulletin summaries released in 2023 can be much shorter — e.g., an 18‑page bulletin/redline summary). Users should confirm which document (full standard vs. redline/bulletin) they need.

Scope

Applies to low‑voltage lighting systems and components intended for permanent installation in accordance with NFPA 70 (NEC) Article 411. Covers Class 2 luminaires and systems, power units with limited outputs (including power units with outputs limited to 25 A and below specified safe voltages), exposed bare conductor systems, POE applications, and other low‑voltage lighting systems. Excludes luminaires and equipment covered by other UL standards (for example UL 153, UL 1574, UL 1598) and does not address certain specialized applications such as hazardous/classified locations, emergency lighting, marine shipboard lighting, horticultural and germicidal luminaires, or luminaires installed over cooking equipment.

Key topics and requirements

• Electrical spacings and clearances for exposed bare conductors and low‑voltage circuits.
• Requirements for power units (output limits, protection, and marking) and Class 2 supply characteristics.
• Marking and labeling requirements for luminaires and power units (wattage, supply ratings, installation cautions).
• Mounting means and mechanical strength tests, including drop/impact tests for luminaires.
• Supply and connection requirements (including supply connections and wiring methods applicable to low‑voltage systems).
• Cross‑references and applicability of provisions from other UL luminaire standards (UL 1598, UL 8750 for LED components).
• Specific limits or requirements added in recent revisions (examples: fuse temperature limits, lithium battery charging voltage limits, mounting options for Class 2 luminaires).

Typical use and users

Manufacturers of low‑voltage luminaires, system integrators, lighting designers, testing laboratories, compliance officers, and certification bodies use UL 2108 to design, test, label and certify low‑voltage lighting systems and power units for safe installation per the NEC. Regulatory authorities, code officials, and procurement teams reference UL 2108 requirements when specifying low‑voltage lighting products for commercial and residential installations.

Related standards

Commonly referenced and related standards include UL 8750 (LED equipment for lighting), UL 1598 (Luminaires), UL 153 (Portable Electric Luminaires), UL 1574 (Track Lighting Systems), UL 1838 (Low Voltage Landscape Lighting Systems) and various transformer and wiring standards (for example UL 5085 series for low‑voltage transformers). The UL 2108 document includes a list of referenced and reverse‑referenced standards for cross applicability.

Keywords

low voltage lighting systems; Class 2; power unit; POE; luminaire; UL 2108; NFPA 70 Article 411; LED components; marking; mounting; safety requirements.

FAQ

Q: What is this standard?

A: UL 2108 is the Underwriters Laboratories Standard for Safety titled "Low Voltage Lighting Systems." It contains requirements for the safe construction, marking, and testing of low‑voltage lighting systems and associated power units.

Q: What does it cover?

A: It covers Class 2 luminaires and low‑voltage lighting systems (including exposed bare conductor systems and POE), power units with limited outputs, and related wiring and marking/installation requirements; it excludes luminaires covered by other UL standards and certain specialized applications.

Q: Who typically uses it?

A: Manufacturers, test labs, certification bodies, lighting designers, installers, and code officials who design, evaluate, certify, procure or inspect low‑voltage lighting systems.

Q: Is it current or superseded?

A: The standard is active and maintained by UL. Edition 2 is the main edition (published December 7, 2015) and redline revisions (including the April 18, 2023 redline) have been published; subsequent revisions (for example September 27, 2024) are also recorded in UL's revision history, so users should confirm the specific redline or revision they require.

Q: Is it part of a series?

A: It is part of UL’s family of lighting and electrical standards and is cross‑referenced with other UL standards for luminaires, LED equipment, transformers, cords and wiring; it functions alongside standards such as UL 8750, UL 1598, UL 153 and UL 1574.

Q: What are the key keywords?

A: Low‑voltage, Class 2, luminaire, power unit, POE, LED, NFPA 70 Article 411, marking, mounting, safety.