Why do street lamps turn on and off?

I’ve never come across this phenomena… obviously I take it this is not just occurring at dawn and dusk…very odd…. hmmmmm

I think I recall hearing, once upon a time, that it’s an energy/cost-saving measure.

By randomly switching off street lamps for short periods throughout the night, a lot of electricity can be saved across the grid and bulb life extended somewhat.

But I agree with you in practice: It seems less random and more of a “wait for someone who’s kinda spooked to be alone in this neighborhood at night and switch off the light, ha ha ha” kind of thing.

Maybe it has a motion detector.

It’s to do with your ‘tiny’ electrical current that passes through your body, into the floor and into the lamp post. Seriously!

When I walk past cashiers desks at work, the tills beep reading zero (when nothing is on them obviously because it’s such a small charge)

But yeah this is totally true and happens a lot.

In fact there’s a lightbulb in my room, that after turning off, I can light again by touching it with my hand.

Think of it like a plasma ball. My hand pulls the electricity through the bulb, like it pulls it to the edge on a plasma ball.

ask richardhenry if you don’t believe me, he lit the whole thing once by spreading both hands across it

it was amazing

@cage so does that explain this I’m kinda hopin’ so!!! I wanna be charged like you !!!

I’ve noticed the streetlight phenomenon when a car passes under a streetlight. Usually that car is light-colored. My guess is that the streetlight reflects off the car, back into the sensor that turns it off during the day. The streetlight is tricked into thinking it’s daylight.

@Grisson oh now that’s disappointing :-( scientific explanations suck!—only kidding

@lynneblundell What’s really disappointing is that I couldn’t come up with a funny reason for it.

Around these here parts, street lights come on at night and turn off for the day in big blocks. If you could bathe one streetlight completely in sunlight, leaving the others in the dark, I’d expect all of them to stay on.

(Possible exception: if there is a single light sensor for the entire block of lights, it might be placed on one of the individual lights. Don’t use that one for my hypothetical above.)

@lynneblundell I’m electric baby

Im with you Box, for some reason I always notice the turn off around me… I think they don’t like me. I think they hope in the darkness I will get mugged…

More answers here, here, and here too!

@ cage
when u are standing on the gorund, shouldnt the electric dispersed right there and not ggoing anywhere else??

something wrong with the lightbulb? whats the motive of doing so? it suppose to turn on when anyone gets near thats to avoid burglary or something.

@mea05key lol, no. It’s a little bulb in a lamp. I’m talking about touching the actual bulb not a sensor. Don’t ask me how it works.

Like I said think of it as a plasma ball. When you touch the glass sides of them, the plasma inside gets attracted to where you are making contact. I think it’s simply pulling the electricity along to where my fingers are making contact with the bulb.

@ cage sorry misunderstood u

Most street light fixtures have built-in switches that turn the lamp off if it detects that the bulb is overheating. If the switch goes bad, it can start falsely detecting overheating at normal operating temperatures. When it does, it turns the lamp off and then turns it back on again. Since these types of lamps take a few minutes to warm up, you get the light constantly cycling every few minutes.

It’s usually an indication of one of three things.
A bulb that’s going bad.
A bad ballast.
A bad photoeye.
These componants can cycle on and off as they heat up and fail. Usually a bad photoeye won’t allow the light to come on at all.