UL 48's labeling change for channel letters, explained
Since July 1, 2024, channel letters fed only by Class 2 wiring can carry one Electric Sign label instead of a section label on every letter. What changed, which signs it covers, and what to tell an inspector who expects a label on each letter.
UL revised UL 48 in December 2023 so that a section sign is one whose parts need wiring other than Class 2 between them in the field, and the marking requirements changed to match on July 1, 2024. Channel letters fed only by Class 2 wiring can now carry a single Electric Sign label, typically on the housing with the branch circuit power and the Class 2 power supply. Signs with branch-circuit power in each section are still labeled section by section.
Key takeaways
- Class 2-fed channel letters can carry one Electric Sign label instead of a section label on every letter. It's an option: a maker can still certify them as section signs.
- The single label typically goes on the housing with the branch circuit power, where the Class 2 power supply is.
- Signs that bring branch-circuit power into each section still get a label on each one, such as Section 1 of 4.
- The ISA warned that inspectors who don't know about the change may fail compliant signs, and suggests handing your inspector its member alert.
- UL 48 is still the 15th edition. Intertek's December 18, 2025 date is a deadline for its own listing reports, not the labeling date.
On this page
- What changed?
- Which signs does it affect?
- Where does the label go now?
- Which signs still get a label on every section?
- Is the single label required?
- Will inspectors accept one label?
- What should a sign shop do?
- What about signs built before July 1, 2024?
- What do the instructions have to say?
- Did UL 48 get a new edition?
- What is the December 18, 2025 date?
A channel letter install can fail inspection over labels that are correct. Here's what UL changed, which signs it covers and how to keep it from costing you a return trip. Everything below is from UL, the International Sign Association and Intertek; the sources are listed at the end.
What changed?
UL revised UL 48 on December 18, 2023 to define a section sign as "a sign shipped as subassemblies that requires other than Class 2 field-wiring between the subassemblies to complete the overall sign." UL's follow-up inspection instructions changed the marking requirements for section signs to match, effective July 1, 2024.
Which signs does it affect?
Multi-housing signs, like channel letters, whose sections are fed only by Class 2 wiring from a power supply. Because nothing but Class 2 wiring runs between the letters in the field, they don't have to be certified as section signs.
Where does the label go now?
UL says these signs only require a single Electric Sign label, typically applied to the housing that contains the branch circuit power, where the Class 2 power supply is located. The ISA describes it as the raceway or enclosure that contains the power supply.
Which signs still get a label on every section?
Signs that bring branch-circuit power into each section, so each section needs field wiring other than Class 2. They're still section signs, labeled one section at a time, such as Section 1 of 4.
Is the single label required?
No, it's an option. UL allows a manufacturer to certify any multi-housing sign as a section sign if that's its preference, so you may still see section labels on every Class 2 letter.
Will inspectors accept one label?
Not all of them, yet. The ISA warned that inspectors who don't know about the change may incorrectly fail channel letter signs with compliant UL labels, because to many of them a missing UL mark on each letter means the sign isn't approved.
What should a sign shop do?
The ISA suggests giving your inspector a copy of its member alert, or asking them to check with their UL contacts. It also helps to say it on the permit drawings, the way the Honeygrow permit set's channel letter sheet notes a single Electric Sign mark on the supply enclosure for its Class 2 letters.
What about signs built before July 1, 2024?
Neither UL nor the ISA addresses them, and nothing we found says existing section labels become invalid.
What do the instructions have to say?
The 2023 revision added that the instructions for these signs identify all the included housing parts and describe how they're meant to be mounted and connected (UL 48, 8.1.3).
Did UL 48 get a new edition?
No. UL 48 is still the 15th edition, published in 2011, with revisions; the most recent is dated May 14, 2025.
What is the December 18, 2025 date?
Intertek's deadline for updating its own listing reports, behind the ETL mark, to the December 2023 revision of UL 48. It isn't the date the labeling change took effect; that was July 1, 2024.
Sources
- UL Solutions: simplified labeling for multi-housing electric signs (Oct 21, 2024)
- UL Code Authority question corner: Class 2 multi-section signs
- International Sign Association member alert: UL labeling update may complicate channel letter sign inspections (Aug 28, 2024)
- Intertek standard update notice: UL 48, revision of December 18, 2023
- UL 48, Standard for Electric Signs, edition 15 (UL standards store)