Safety Devices & UL 325 Compliance
Photo eye mounting, safety edge devices, cable tension monitors, UL 325 entrapment requirements, and warning tags.
- Mount and align photo eyes at the correct height
- Explain UL 325 entrapment protection requirements
- Describe cable tension monitor function and jackshaft safety features
- Identify required warning tags, safety labels, and documentation
Lesson 1
Photo Eye Height, Mounting & Alignment
Photo Eye Function
Photo eyes (also called photoelectric sensors or safety sensors) are an entrapment protection device required by UL 325 on all residential garage door openers. They consist of a sending unit (infrared LED transmitter) and a receiving unit (infrared sensor) mounted on opposite sides of the door opening near the floor.
When the invisible infrared beam between the sensors is broken by a person, pet, or object while the door is closing, the opener immediately reverses direction and returns the door to the fully open position. If the beam is broken before the close command is given, the door will not close at all.
Mounting Requirements
Photo eyes must be mounted no higher than 6 inches above the garage floor. This height ensures the beam is low enough to detect a small child crawling under the door. The recommended mounting height is 4 to 6 inches.
Both sensors must be:
- Mounted on the vertical track brackets, door jambs, or dedicated mounting brackets
- Aligned so the beam crosses the full width of the door opening
- Protected from damage by vehicles or foot traffic
- Securely fastened so they do not shift out of alignment from vibration
Photo eyes must be mounted no higher than 6 inches above the floor to detect small children. Both sensors must be aligned with an unbroken infrared beam across the full door width.