Power outage + loud boom. Should I be worried?

December 17, 2015 10:18 AM

About 15 minutes ago I heard a loud booming noise outside; the power in the whole house went out almost simultaneously. I reported the outage but can't get in touch with a live person. What could this be? Should I be worried? Should I try touching my fuse box?

I don't know much about electrical power, but I did some googling and my best guess is that a transformer blew somewhere (I didn't even know what a transformer was...). My fuse box is on, so it didn't flip off or anything even though the power went out. I haven't touched the fuse box due to the loud booming noise.

What could this be? Should I try flipping the switches, or could this be dangerous? The estimated time for repair is about two hours and I would normally wait, but the loud noise scares me since I have never heard it before. Please help me, MeFite electricians!

posted by BuddyBoo to Home & Garden (22 answers total)

Response by poster: Whoops - I have a breaker panel, not a fuse box (I think...)
posted by BuddyBoo at 10:19 AM on December 17, 2015

Transformers can make a very loud noise if they go. The transformer won't be in your house, though. Can you see if anyone else nearby has power?

Otherwise, I would call for repair and don't worry about it. Just avoid any power lines that are on the ground.
posted by selfnoise at 10:21 AM on December 17, 2015 [7 favorites]

sounds reasonable. a transformer went bang here a year or two back. was pretty spectacular, with flames.

anyway, there's nothing much for you to do. just wait til the power comes back. you can turn off anything unimportant that was on when the power went, so that when the power does return there's less of a surge, but that's about all.

your circuit breaker panel is safe. if the switches have stayed in the "on" position then the problem isn't at your end.

relax. you're fine.
posted by andrewcooke at 10:22 AM on December 17, 2015 [6 favorites]

Don't panic. Yes, the loud noise was a transformer shorting out somewhere in your neighborhood. Relax. Go for a walk, you might find the repair crew. It's not inside your house, or the power company would not be giving you an estimated time for repairs. You could check with your neighbors, to be absolutely sure — I guarantee their power is out, too.
posted by beagle at 10:22 AM on December 17, 2015 [1 favorite]

Yeah, it does sound like a blown transformer. We had one blow right next door a few months ago, and it sounded like a bomb had gone off. That took something like six hours, but we got to watch them replace it from our bedroom window, which was pretty cool.
posted by ernielundquist at 10:26 AM on December 17, 2015 [1 favorite]

Oh, and if you have a desktop computer or anything else with a boot process it goes through, don't turn it back on right away when the power comes back. Our power was out the other day for a short time, and after it came on, I turned my computer on, only to have the power go out again briefly during the boot process, which corrupted my filesystem.

Give it fifteen minutes or so, probably, just to make sure the power is really back for good and not just sputtering to life.
posted by ernielundquist at 10:38 AM on December 17, 2015 [3 favorites]

Oh and, since you asked, no need to flip any switches, except unplugging your computer as suggested. When power comes back, everything will just come back to life.
posted by beagle at 10:48 AM on December 17, 2015

Yep, transformer. It's VERY LOUD but there's no danger. (Sometimes, especially on a clear night, you can hear them quite some distance away -- it may not be nearly as close as it sounded.) If you mosey out into the street you may be able to tell if any of your neighbors have power (pro-tip: learn which of your neighbors leave porch lights on 24/7, so you can tell if those houses lost power). If they don't, it's almost certainly a big transformer serving your neighborhood.

Turn off your computer and make sure you leave at least one lightswitch on so you'll notice when the power comes back on! (It scares the bejeezus out of me when the whole house comes back on at once, so I often turn off all but a couple of things, so when it comes back it's just a couple of lights (and all the things that beep, God, everything beeps now). But that's just so I don't jump out of my skin, the appliances/lights/etc. don't need it.)
posted by Eyebrows McGee at 10:54 AM on December 17, 2015 [2 favorites]

The nearby transformer may not itself have exploded. Instead, a large fuse associated with it may have blown. Perhaps a squirrel has met a quick end on some wires. The power company will come and identify it, and replace the fuse. This is an interesting process to watch.

During a hurricane the sound of transformers blowing and the flashes of wires arching is part of the scene. Once the storm is passed the crews will be out to do their jobs and get power back to the neighborhoods.
posted by Midnight Skulker at 10:59 AM on December 17, 2015

What I normally do in cases like this is, go for a walk, too, in order to look whether it's only me that hasn't got any lights. Most of the time, it's a whole block or something...
posted by Namlit at 10:59 AM on December 17, 2015 [1 favorite]

This probably goes without saying, but do turn off any toasters, irons, electric stoves, blenders, etc. -- assume you won't be home when the power comes back on, so turn off anything that you need to actively monitor to keep it from causing a fire or otherwise creating havok.
posted by salvia at 11:02 AM on December 17, 2015 [2 favorites]

Yes, that was probably a transformer blowing. One blew right outside my apartment and the explosion was preceded by some tesla coil-esque zapping sounds and followed by a blast of white light. It sounded like a bomb going off, and my cats thought the world was ending. So did I, for a minute.

If you don't have all of your sensitive electronics on surge protectors, now would be an excellent time to remedy that.
posted by ananci at 11:18 AM on December 17, 2015 [1 favorite]

It's fine, you're fine. The loud noise was likely the transformer, though it could have been an auto-vs-pole or similar vehicle/equipment collision, industrial accident, or other incident somewhere on the grid, but in any case nothing happened to your house or your breaker box. You can go touch it all you want, but it's not going to fix the transformer. Your breaker switches will almost never be affected by a power issue that occurs beyond your house, though sometimes some of them will cut over if your house gets struck by lightning or a transformer very close to your residential tap blows. But really breakers are for the internal protection of your house circuits generally.

It is traditional in my neighborhood to go stand around outside looking confused for 10 minutes after a power outage, basically long enough for everyone to go "oh, you too? okay then" and go back inside.

If you know your neighbors and know that any of them are elderly and/or reliant on home oxygen or other full-time electrical medical support you might go tap on the door and make sure they're okay. Home O2 supplies have battery backups but most cities have an emergency protocol for getting those people a generator or sending an ambulance, and someone who is oxygen-deprived may waffle or get confused about calling 911 or the power company emergency line.
posted by Lyn Never at 11:19 AM on December 17, 2015 [4 favorites]

My electrical provider has outage maps and info on their website. It's a good way to check to see if an outage is just your house or widespread. They'll also give est times for restoration.
posted by saffry at 11:20 AM on December 17, 2015 [1 favorite]

As an added note of calm, this happens like every other goddamn week where I live. bang and the lights go out. It's a very distinctive sound that travels. I wouldn't like to stand under a transformer going pop, but otherwise it's quite safe.

The only danger is there might be powerlines actually pulled down onto the road, if you live somewhere where they're strung up on poles instead of underground (and if you have trees big enough to drop branches onto the lines).
posted by BungaDunga at 11:28 AM on December 17, 2015 [2 favorites]

Oh, I promise last thing: I will get a rough idea of the size of outages by checking for wifi signals on my tablet. There are usually plenty of them, so if I can't see any, I figure power's out for at least a block or two.

(I have a lot of power outages for some reason.)
posted by ernielundquist at 11:45 AM on December 17, 2015 [5 favorites]

PCBs were almost universally used as transformer oils "well into the 70s", and in my relatively forward-looking city an elaborate, enormous and hugely expensive five stage furnace was constructed occupying an entire block of a city street to burn the oil from substations, but as far as I know, nothing was done then about the oil in transformers on poles -- and those transformers can last a long time.

If oil has leaked out of the transformer that blew, I wouldn't park my car next to that pole or let my kids play under it.
posted by jamjam at 11:49 AM on December 17, 2015 [1 favorite]

In addition to checking your power, see if you can't check the 911 active calls in your area. An exploding substation (a pretty common event) is usually good for a fire call in addition to the numerous "some exploded" calls that 911 gets when this sort of thing happens. I usually find out about this on my city's subreddit, in fact, because someone posts "did anyone else hear that bang?"
posted by Sunburnt at 11:57 AM on December 17, 2015

Typically, in my neighborhood, a blown transformer requires 4-6 hours for a fix. The electric company can tell somethings blown, but we see truchs driving around trying to find exactly what. Hint: its the one where the little light is out. Then it takes some time to marshal forces, get the new parts, etc.
posted by SemiSalt at 12:41 PM on December 17, 2015

It's a transformer. When they blow it's pretty spectacular. Do nothing- but yes, go take a walk, to check it out. I have experienced this several times.
posted by St. Alia of the Bunnies at 1:39 PM on December 17, 2015

Actually, it is not likely a transformer blowing. It is more likely the high voltage circuit breaker protecting the transformer. Compressed gas is used to assist the rapid opening of the circuit and to extinguish the arc that flows between the open contacts. Just like your home circuit breaker, no permanent damage is done. The crews have to clear the short circuit that caused the breaker to trip, for example a fallen tree, and then the reset the breaker.

You can see a test of a circuit breaker in this 9-second youtube video.
posted by JackFlash at 2:21 PM on December 17, 2015 [1 favorite]

Nthing that it sounds like a transformer. Is it very cold there right now? My old neighborhood would have a couple of these minor explosions and associated outages almost every winter.
posted by Jacqueline at 11:55 PM on December 17, 2015