Channel Letter Glossary

Underwriter’s Laboratories (UL) is an independent product safety certification organization. UL approval means that all sign components meet UL standards for electrical safety.

The flexible plastic edging that surrounds a channel letter’s face. Trim caps are chemically welded to the letter face, and are available in a variety of colors.

A device than changes the incoming voltage level to the level required by the sign illumination. Channel letter transformers are typically either “step up” (incoming voltage level is increased), or “step down” (incoming voltage level is decreased.) LED channel letters usually utilize a “step down” transformer. Transformers are also called power supplies.

The outline of a font. The greater the stroke weight, the thicker the font.

The side of a channel letter. Returns are commonly constructed of aluminum, and range from 3″ to 8″ deep.

A raceway is a separate, optional rectangular structure upon which channel letters can be mounted. Raceway mounted letters are mounted to the front of the raceway instead of the actual building substrate. Channel letters are pre-installed on the raceway which simplifies the field sign installation. Raceways are typically constructed of aluminum.

A protective plastic piece cut to the same shape as a reverse channel letter and attached to seal the back. This prevents rainwater entry and also keeps animals from nesting inside the letter. Polycarbonate backs also provide mounting surfaces for neon tube supports.

A legal document required by a city or municipality that allows the installation of a specific sign at a designated location. A permit must be obtained prior to installing a sign.

An electronic light source for channel letters. LED stands for Light Emitting Diode, and this type of illumination is caused by the movement of electrons in a semiconductor material. LED Channel letters are becoming more and more prevalent.

Small holes placed at the bottom of a channel letter’s return. Drain holes prevent water from accumulating in a letter’s interior.