I have a PCB mounted inside an enclosure with onboard LEDs for status indication. The LEDs aren’t visible from outside. What are the most reliable techniques to bring the LED outside of a sealed enclosure
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The most common and reliable solution is a light pipe. It allows an onboard LED to be visible on the enclosure exterior without compromising the seal or adding wiring.
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Light pipes work with both SMT and through-hole LEDs. Optical details affect appearance more than function: a polished or domed tip gives a directional indicator, while a matte finish provides wide-angle visibility. Matching the LED’s emission pattern to the light pipe improves efficiency but is usually not critical for status indicators.
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When the enclosure wall is thick or PCB positioning isn’t tightly controlled, a panel-mounted LED with sealed feedthrough can be more practical. The onboard LED is omitted, and the status signal is routed electrically to an IP-rated indicator mounted in the enclosure wall with an O-ring seal.
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Beyond light pipes, the choice often comes down to mechanical and assembly trade-offs. You can align the PCB behind panel holes for direct visibility (low cost, not sealed), use a small LED sub-PCB connected by a short cable for layout flexibility, or use panel-mount/bezel LEDs wired back to the board for sealed enclosures at the cost of extra assembly.
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A small, sealed indicator light with a pigtail connector is a reliable alternative. You can mount it directly in the enclosure wall using an O-ring or epoxy seal for integrity, and connect it via its short wires to pads or pins on your internal PCB. This keeps your main board sealed inside while placing the light source exactly where needed.
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