In the United States, electric signs must comply with the provisions of the National Electric Code Article 600 and Underwriters Laboratories 48 Standard for Electric Signs.
Now in its 15th edition, UL 48 requirements cover all electric signs, art forms, outline lighting and skeleton neon tubing. For decades, ISA has taken a leading role in the development of UL Standards that keep pace with advances in electric sign technology.
Since its first edition in 1917, UL 48 has developed norms and guidelines that have harmonized the design and manufacture of electric signs that operate safely.
Other related UL Standards (like UL 879 Standard for Electric Sign Components and UL 2161 Standard for Neon Transformers and Power Supplies) develop the requirements for components designed for use in UL 48 electric signs. (UL 48 is available for purchase in the UL Shop.)
The UL 48 Standard is being revised continuously, with the fifteenth edition published in 2011. Since the release of the 15th edition, UL 48 also includes 4 smaller “revisions” and numerous “bulletins” updating proposed changes.