# Are transformers in cities dangerous? **URL:** \ **Category:** Factual Questions\ **Created:** [August 31, 2015, 9:28pm UTC](https://boards.straightdope.com/t/are-transformers-in-cities-dangerous/729545 "2015-08-31T21:28:07Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![dasklme](https://avatars.discourse-cdn.com/v4/letter/d/f0a364/32.png) [@dasklme](https://boards.straightdope.com/u/dasklme)\ **Post date:** [August 31, 2015, 9:28pm UTC](https://boards.straightdope.com/t/are-transformers-in-cities-dangerous/729545/1 "2015-08-31T21:28:07Z")
[This three-phase transformer](http://postimg.org/image/ohwb5k5zr/) is right across from my bedroom window, probably about 8’ away. Should I be concerned? How much voltage is likely being converted by the unit in the picture? ---
**Author:** ![boffking](https://avatars.discourse-cdn.com/v4/letter/b/858c86/32.png) [@boffking](https://boards.straightdope.com/u/boffking)\ **Post date:** [August 31, 2015, 9:37pm UTC](https://boards.straightdope.com/t/are-transformers-in-cities-dangerous/729545/2 "2015-08-31T21:37:00Z")
The only time to be concerned is during a snow or ice storm. The transformers sometimes explode in these storms. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [August 31, 2015, 9:37pm UTC](https://boards.straightdope.com/t/are-transformers-in-cities-dangerous/729545/3 "2015-08-31T21:37:33Z")
Dangerous as in emitting some sort of harmful radiation? Probably not. They can be dangerous though - those metal cans are filled with oil - which can catch fire that gets out of control really quick. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [August 31, 2015, 9:48pm UTC](https://boards.straightdope.com/t/are-transformers-in-cities-dangerous/729545/4 "2015-08-31T21:48:26Z")
Those are distribution transformers. They convert the distribution voltage, which is anywhere from about 3,000 to 12,000 volts or so, down to the 240 volts that is used to create your 120/240 volt service. That looks to be an older area, which means that the distribution voltage is probably on the lower side of that range. I wouldn’t recommend climbing up on the pole, but other than that, the transformers are fairly safe. You may find some stuff on the internet about how power lines cause cancer or other bad health issues. Most of what is on the internet on that subject is complete crap. Most of it stems from a study done in the 1970s that found a link between power lines and childhood leukemia. That study was later discredited, and despite decades of expensive research, no one has yet managed to find any sort of conclusive link between power lines and ill health effects, or even proposed a mechanism by which it could happen. The one thing that is true is that people who live next to transmission lines (20,000 to 500,000+ volts) statistically don’t live as long as people who don’t, and we don’t really know why. It may just be that people who choose to live healthy lifestyles also choose not to live next to big transmission lines. If the transformer rusts through and the oil leaks out, it might explode. That’s pretty rare. A squirrel could climb on top of it and short it out, which isn’t quite so rare. The transformer might catch fire and might eventually explode. It looks like your window is at enough of an angle that even if the transformer were to explode, the wall would shield you from just about all of it. Transformers like that are everywhere in cities. They really aren’t anything worth worrying about. Transformer explosions do happen from time to time, but the chances of any of those particular transformers exploding is very small. ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [August 31, 2015, 9:49pm UTC](https://boards.straightdope.com/t/are-transformers-in-cities-dangerous/729545/5 "2015-08-31T21:49:50Z")
The primary voltage is likely somewhere between 2,000 and 35,000 VAC, depending on the distance from the high voltage transformers. Those are not high voltage transmission lines, just city distribution lines, and are probably nearer the lower end of that range. I can’t see the insulators on the primary lines, so it’s hard to tell. As for the transformer, 3 feet is usually the minimum clearance for low voltage, so you’re fine. ---
**Author:** ![Don\_t\_Panic](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/don_t_panic/32/398_2.png) [@Don\_t\_Panic](https://boards.straightdope.com/u/Don_t_Panic)\ **Post date:** [August 31, 2015, 10:19pm UTC](https://boards.straightdope.com/t/are-transformers-in-cities-dangerous/729545/6 "2015-08-31T22:19:17Z")
> [@dasklme](#): > > Are transformers in cities dangerous? I’m going with [“yes”](https://youtu.be/Ripru5tYe9Q?t=204). Oh, wait. I think I may have misunderstood this thread. ---
**Author:** ![Kent\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kent_clark/32/105_2.png) [@Kent\_Clark](https://boards.straightdope.com/u/Kent_Clark)\ **Post date:** [September 1, 2015, 1:40am UTC](https://boards.straightdope.com/t/are-transformers-in-cities-dangerous/729545/7 "2015-09-01T01:40:00Z")
> [@boffking](#): > > The only time to be concerned is during a snow or ice storm. The transformers sometimes explode in these storms. We had an ice storm here a few years back that had transformers blowing all over town. They seem to be made so that the top blows off relatively harmlessly, like the cap on a pressure cooker. ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [September 1, 2015, 1:51am UTC](https://boards.straightdope.com/t/are-transformers-in-cities-dangerous/729545/8 "2015-09-01T01:51:17Z")
When they blow, there can be fire and spilled oil, but at least you no longer have PCBs to worry about. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [September 1, 2015, 2:46am UTC](https://boards.straightdope.com/t/are-transformers-in-cities-dangerous/729545/9 "2015-09-01T02:46:36Z")
Said another way: \*Can \*something bad happen? Sure. Statistically speaking, \*will \*something bad happen to that transformer while you live there? Almost certainly not. ---
**Author:** ![guizot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/guizot/32/3636_2.png) [@guizot](https://boards.straightdope.com/u/guizot)\ **Post date:** [September 1, 2015, 6:36am UTC](https://boards.straightdope.com/t/are-transformers-in-cities-dangerous/729545/10 "2015-09-01T06:36:20Z")
> [@engineer\_comp\_geek](#): > > If the transformer rusts through and the oil leaks out, it might explode. That’s pretty rare. A squirrel could climb on top of it and short it out, which isn’t quite so rare. The transformer might catch fire and might eventually explode. It looks like your window is at enough of an angle that even if the transformer were to explode, the wall would shield you from just about all of it. I can recall at least two–maybe three–occasions of one these things exploding near my residence, so it’s not that rare. But no one was ever hurt, and there didn’t appear to be any damage except to the transformers themselves. From what I’ve witnessed, and from looking at the picture, I don’t think the OP should worry. ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [September 1, 2015, 12:17pm UTC](https://boards.straightdope.com/t/are-transformers-in-cities-dangerous/729545/11 "2015-09-01T12:17:21Z")
> [@kunilou](#): > > We had an ice storm here a few years back that had transformers blowing all over town. They seem to be made so that the top blows off relatively harmlessly, like the cap on a pressure cooker. If you were hearing loud “Bang” sounds, it was probably the fuses feeding the transformers. Those go off damn near like a stick of dynamite when they blow. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [September 1, 2015, 12:42pm UTC](https://boards.straightdope.com/t/are-transformers-in-cities-dangerous/729545/12 "2015-09-01T12:42:10Z")
> [@jz78817](#): > > If you were hearing loud “Bang” sounds, it was probably the fuses feeding the transformers. Those go off damn near like a stick of dynamite when they blow. These are [expulsion fuses](https://en.wikipedia.org/wiki/Fuse_(electrical)#High_voltage_fuses). They are designed so that when the element shorts out, the heat ignites a surrounding matrix of propellant that generates a violent blast and blows the vaporized conductor material out into the air. The idea is to rapidly disrupt the conductive path and eliminate a prolonged period of arcing that might otherwise occur if an ionized path across the gap is allowed to persist. ---
**Author:** ![Kent\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kent_clark/32/105_2.png) [@Kent\_Clark](https://boards.straightdope.com/u/Kent_Clark)\ **Post date:** [September 1, 2015, 9:14pm UTC](https://boards.straightdope.com/t/are-transformers-in-cities-dangerous/729545/13 "2015-09-01T21:14:01Z")
> [@jz78817](#): > > If you were hearing loud “Bang” sounds, it was probably the fuses feeding the transformers. Those go off damn near like a stick of dynamite when they blow. In addition to the BANG, there were strangely beautiful green flashes from every transformer. It reminded me of some sort of 4th of July performance art. ---
**Author:** ![Dewey\_Finn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dewey_finn/32/4222_2.png) [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)\ **Post date:** [September 1, 2015, 11:02pm UTC](https://boards.straightdope.com/t/are-transformers-in-cities-dangerous/729545/14 "2015-09-01T23:02:53Z")
> [@engineer\_comp\_geek](#): > > Transformers like that are everywhere in cities. Not just cities. They’re also common in the suburban neighborhoods where I grew up. And actually, since some larger cities have underground utilities, they might be _less_ common in cities than in more rural areas. ---
**Author:** ![Jragon](https://avatars.discourse-cdn.com/v4/letter/j/e19b73/32.png) [@Jragon](https://boards.straightdope.com/u/Jragon)\ **Post date:** [September 1, 2015, 11:04pm UTC](https://boards.straightdope.com/t/are-transformers-in-cities-dangerous/729545/15 "2015-09-01T23:04:52Z")
Only if they’re Decepticons. ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [September 2, 2015, 1:25am UTC](https://boards.straightdope.com/t/are-transformers-in-cities-dangerous/729545/16 "2015-09-02T01:25:23Z")
> [@kunilou](#): > > In addition to the BANG, there were strangely beautiful green flashes from every transformer. It reminded me of some sort of 4th of July performance art. ah. the green flashes were from copper being burned away, so yeah it sounds like the transformer (or at least the attached wire/cable) went “BZZZZZT.”