# What are those little orange thingies on top of street lights? **URL:** \ **Category:** Factual Questions\ **Created:** [January 9, 2005, 4:33pm UTC](https://boards.straightdope.com/t/what-are-those-little-orange-thingies-on-top-of-street-lights/283893 "2005-01-09T16:33:37Z")\ **Posts on this page:** 8\ **Page:** 2
**Author:** ![manhattan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/manhattan/32/7_2.png) [@manhattan](https://boards.straightdope.com/u/manhattan)\ **Post date:** [February 4, 2005, 4:44am UTC](https://boards.straightdope.com/t/what-are-those-little-orange-thingies-on-top-of-street-lights/283893/21 "2005-02-04T04:44:14Z")
> [@Eats\_Crayons](#): > > Is there a picture anywhere of **stuyguy** ’s tennis-ball-can fire thingy for comparisson? Now, I’m curious. Took one just for this thread. You have to have a free imagestation membership to see it, I think, but it’s [here](http://www.imagestation.com/picture/sraid156/pf8be9f5b296ab31bd45a60209b40c2e9/f53dda92.jpg). If someone wants to rehost it someplace more convenient, it ain’t exactly gonna be a profit center for me, so no copyright worries. 😉 Also, sorry for the quality – I compressed it all to heck for space reasons and it lost a little something. ---
**Author:** ![Thinktank](https://avatars.discourse-cdn.com/v4/letter/t/6a8cbe/32.png) [@Thinktank](https://boards.straightdope.com/u/Thinktank)\ **Post date:** [February 4, 2005, 5:38am UTC](https://boards.straightdope.com/t/what-are-those-little-orange-thingies-on-top-of-street-lights/283893/22 "2005-02-04T05:38:29Z")
Wow, Pigeon Cameo and all! :Dlol… u dun guud, hahaha ---
**Author:** ![octothorpe](https://avatars.discourse-cdn.com/v4/letter/o/b77776/32.png) [@octothorpe](https://boards.straightdope.com/u/octothorpe)\ **Post date:** [February 4, 2005, 6:22am UTC](https://boards.straightdope.com/t/what-are-those-little-orange-thingies-on-top-of-street-lights/283893/23 "2005-02-04T06:22:26Z")
> [@](#): > > Originally posted by **Q.E.D.** > Right, and they haven’t always been on top of the lamps, either. Some were mounted as separate devices on top of a pole, for instance. Again, these would normally control a bank of lamps. I don’t know specifically what benefit the newer sensor types offer, but my guess is that they are less prone to false “off” triggering by car headlights and other artificial light sources. Generally speaking, the devices you refer to are used to control a series street light or ‘arc’ circuit. Series street lights use a constant-current transformer (also referred to as a regulated-output or ‘RO’ transformer) that operates at 6.6 amps and adjusts voltage to maintain that current. Although the voltage fluctuates dependent on the load, arc circuits operate on ‘primary’ voltage (nominally 2400v) and photocells designed to operate at that voltage would be cumbersome and expensive. As such, a photocell housed in a standard meter socket and operating on 120 or 240 volts controls a relay which switches the lights on or off. As this is a series circuit, you cannot switch the power off to an individual bulb as you would open the circuit and all lights would go off (for those of you old enough to remember, think of the Christmas lights you had as a kid and the frustration of locating the burnt-out bulb). This presented a bit of a problem in the early days of arc circuits in that a lamp burning out would cause the entire circuit to go out. This was solved ingeneously by placing a non-conductive disc between 2 contacts in the lamp housing. While the lamp was intact, the disc would keep the contacts apart. When the lamp burned out, the RO would raise the voltage in an attempt to maintain the 6.6 amps and once the voltage reached a high enough level, the disc would ‘burn through’ allowing the contacts to close and restoring the circuit; and serendipitously, allowing the utility workers to identify the lamp in need of replacement. Arc circuits are being phased out across the US for safety reasons. Should a break occur in the circuit, the RO will raise the voltage on the circuit to the stops (2400 volts). While this doesn’t present a problem as long as the conductor is in the air, if a wire should break or fall to the ground, it would not necessarily blow a fuse and pedestrians or motorists may come in contact with the energized primary. Cities across the nation are forgoing the installation of new arc circuits and are installing 120 or 240 volt _parallel_ circuit street lights instead. They are both cheaper and safer in the long run. Fiat Lux, # ---
**Author:** ![hugo\_rodz](https://avatars.discourse-cdn.com/v4/letter/h/9e8a1a/32.png) [@hugo\_rodz](https://boards.straightdope.com/u/hugo_rodz)\ **Post date:** [October 14, 2012, 5:11am UTC](https://boards.straightdope.com/t/what-are-those-little-orange-thingies-on-top-of-street-lights/283893/24 "2012-10-14T05:11:32Z")
> [@zev\_steinhardt](#): > > A friend of mine recently brought this question to my attention. I had no idea of the answer, but I figured that if anyone would be able to provide an answer, you guys would… > > On the tops of many street lights in New York City, there are these little orange thingies. They sort of resemble little orange lights. What the heck are they? > > Zev Steinhardt those orange lights on the lampost indicate there is a alarmbox or firebox to call the fire department ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [October 14, 2012, 5:24am UTC](https://boards.straightdope.com/t/what-are-those-little-orange-thingies-on-top-of-street-lights/283893/25 "2012-10-14T05:24:20Z")
> [@hugo\_rodz](#): > > those orange lights on the lampost indicate there is a alarmbox or firebox to call the fire department You didn’t actually _read_ any posts in the thread past the first, did you? Or notice the dates? Or look at the pictures? Although I’ll admit most pix are gone, due to the dates. NYC was different way back in 2005, and some of the posters were alive then. ---
**Author:** ![running\_coach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/running_coach/32/15836_2.png) [@running\_coach](https://boards.straightdope.com/u/running_coach)\ **Post date:** [October 14, 2012, 1:41pm UTC](https://boards.straightdope.com/t/what-are-those-little-orange-thingies-on-top-of-street-lights/283893/26 "2012-10-14T13:41:21Z")
> [@hugo\_rodz](#): > > those orange lights on the lampost indicate there is a alarmbox or firebox to call the fire department Why would anyone look put an indicator on top of a streetlight when a sign or marker at street level would be far more logical? ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [October 14, 2012, 2:01pm UTC](https://boards.straightdope.com/t/what-are-those-little-orange-thingies-on-top-of-street-lights/283893/27 "2012-10-14T14:01:09Z")
zombie or no these were identified in messages 11 and 12 and confirmed to be the object of the OP in message 15. ---
**Author:** ![postcards](https://avatars.discourse-cdn.com/v4/letter/p/8e8cbc/32.png) [@postcards](https://boards.straightdope.com/u/postcards)\ **Post date:** [October 14, 2012, 2:50pm UTC](https://boards.straightdope.com/t/what-are-those-little-orange-thingies-on-top-of-street-lights/283893/28 "2012-10-14T14:50:55Z")
> [@runner pat](#): > > Why would anyone look put an indicator on top of a streetlight when a sign or marker at street level would be far more logical? Because a street-level sign can’t be seen from a distance of a block or more, whereas an indicator on high can. [Previous page](https://boards.straightdope.com/t/what-are-those-little-orange-thingies-on-top-of-street-lights/283893.md?page=1)