The New Hotness

One of our regular walks takes us up the hill on Old Sivermine Place and, being that type of guy, I tend to look at the infrastructure. The LED streetlights along the road sit atop wood poles and are obviously retrofits. Placards on some poles announce “277 V”, which means they’re fed from one leg of a three-phase 480 V wye service, making their casual mid-air wire-nut spliced connections seem … inappropriate.

Anyhow, they’re supposed to look like this:

In reality, having multiple emitters comes in handy:

Typical 12 V systems have parallel strings of three LEDs in series, so you (well, I) often see automobiles with three adjacent dead LEDs. That turned out to be true with the 15 V (-ish) LEDs in the HQ Sixteen machine I’ve been refurbishing.

These streetlights apparently have individual LED drivers, allowing single LEDs to go dark without affecting the rest. This one has five deaders, so the rot is spreading:

There seems no pattern to the failures:

Those fixtures are in order from the top of the hill downward.

Each light has its own photosensor to decide when to turn on. We don’t go walking after dusk, but at least one light will always be glowing brightly in middday; the sensors aren’t doing well, either.