What would cause all power sockets to stop working?

March 25, 2017 6:11 AM

It's late Saturday night and suddenly all our power sockets have gone dead. (Lights and aircon are still fine). Anything we can do while waiting until we can get an electrician out (which might be Monday)? Or any ideas about what might have caused it?

This is in a 4 Br house, so I'd expect them to be on a few different circuits, but it's everything except the oven that's stopped working. Kitchen, bathroom, bedrooms, fridge etc. The fuse box seems fine: no blown fuses at all. We turned them all off and on again to make sure, including the mains. When it happened we were not doing anything electricity-heavy - just using a laptop and a desktop computer. There have been storms all week, but none in the last 24 hours and no obvious water damage anywhere.

posted by lollusc to Home & Garden (20 answers total)

Response by poster: (This is in Australia, in case that's relevant.)
posted by lollusc at 6:12 AM on March 25, 2017

You probably have two-phase power. In addition to breakers for each individual circuit, your breaker box (or service entrance) likely has a large fuse or breaker for each phase. If outlets are all on one phase, with lights and HVAC on the other, you'd get those symptoms.

(If none of that made sense, call an electrician. Please don't kill yourself with the high voltage.)
posted by sourcequench at 6:19 AM on March 25, 2017

Response by poster: Ok that makes sense but everything in the circuit box seems fine. All the breakers are on the on position, and we switched them to off and on again just on case. Wouldn't your scenario mean one of the larger breakers would have to be in the off position, ie have tripped?

(We will be calling an electrician rather than doing anything complicated, but at midnight on a Saturday it's a while before we'll get one out here, so trying to understand the problem and try any easy fixes in the meanwhile.)
posted by lollusc at 6:28 AM on March 25, 2017

It's also possible something is wrong at the upstream power provider; you might consider calling your power company.
posted by jferg at 6:31 AM on March 25, 2017 [1 favorite]

Have you asked your neighbors if their power is OK? If one of the phases is down because of an upstream problem they'll be having similar issues.
posted by Dr Dracator at 6:40 AM on March 25, 2017 [1 favorite]

jferg might be having a point. We (different country, but whatever) recently experienced some selective-dropout patterns with no circuit-box-related logic when a tree fell over a line further uphill. And yes, ask the neighbors, if possible at this hour.
posted by Namlit at 6:47 AM on March 25, 2017

Response by poster: Yeah, I don't think I can bug my neighbours at this hour of the night, but I'll definitely try them in the morning before calling an electrician. My power company's website and Twitter account say there are no current faults in this area though, but maybe they aren't up to date.
posted by lollusc at 6:51 AM on March 25, 2017

Unless it's going to cost you a lot if it turns out to be on your end, I'd call the power company now.
posted by wierdo at 7:19 AM on March 25, 2017 [1 favorite]

You may have "lost one leg" of the power coming into your main. It will not trip a breaker but will drop out part of your circuits. If so, it's electrician time.
posted by mightshould at 10:16 AM on March 25, 2017 [1 favorite]

Maybe there's a GFCI outlet wired in line on that circuit, which has tripped? Nice explanation here.
posted by nicwolff at 10:25 AM on March 25, 2017 [1 favorite]

Your story sounds exactly like when we lost one leg of our electrical service. Other than cold weather there were no storms or anything unusual. Only our house was affected because it was apparently a fault in one underground connection leading to our house. The power company came out and went behind the meter and put both sides of our house on the same working leg until their sub-contractor could get out and (yes) dig into frozen ground in December to fix the bad connection. By the way, when they started digging I went out and emphasized to them that our entire house was working on one leg, and to please not just repair the other before having the power company come out and undo their temporary fix. He said they knew that, but something in his eyes made me wonder if he did.
posted by forthright at 4:32 PM on March 25, 2017

Response by poster: I am an idiot :) It turned out that the RCD safety switch in the meter board is in the correct position when it is OFF and RED, not when it is ON and GREEN. It must have tripped, and then when we went out to look at the breaker box all the switches were in the on position, so we assumed they were correct. We turned them to off and then back to on, including the safety switch, which was of course supposed to be off. So it was just a matter of flipping that back to the off position and it fixed the problem.

(Unfortunate that we had to pay an electrician $100 to learn this, and now I feel really dumb, but that's life, I guess. And I don't feel too dumb because the neighbours on both sides, who claimed to have more knowledge about electricity than I do, took a careful look at the breaker box too before we gave up and called someone.)
posted by lollusc at 6:07 PM on March 25, 2017 [3 favorites]

Just as an addendum for any future readers in Aus (& possibly other 240v countries): houses here are typically fed by a single phase, so answers suggesting you may have "lost a phase" are likely incorrect.

And lollusc, don't feel dumb. I'm the son of an electrician, have held an electrical licence myself, have seen & tested many RCDs in commercial/industrial switchboards, etc - and still the RCDs in my place have caught me out a number of times...
posted by Pinback at 8:11 PM on March 25, 2017 [1 favorite]

For future use, you may want to put a note on the breaker box about this if you haven't already.
posted by Slinga at 8:47 PM on March 25, 2017 [2 favorites]

Response by poster: Thanks, Pinback. I thought the two-phase idea seemed plausible, because we do have two separate "mains" switches in the circuit box. But the electrician said one is for the hot water system, which is on its own meter to take advantage of night time cheap rates, which I guess I knew and should have realised was the reason for the second mains switch. (I have now been labelling everything in the circuit box to save future confusion!)
posted by lollusc at 9:30 PM on March 25, 2017 [1 favorite]

Okay, I confess I don't understand how the RCD can be off when it is on and on when it is off. Seems it should work like all the other breaker switches.
posted by JackFlash at 10:20 PM on March 25, 2017

Response by poster: Well to be precise: all the other switches are on when they are pointing downwards; the RCD switch must be pointing upwards. When the RCD switch points downwards, it is green. When it points upwards, it is red. I took the combination of these two facts to mean that it should be off. I suppose it is possible that it should be on, but that "on" in this case is signified by pointing the opposite way from all the other switches, and showing red instead of green.
posted by lollusc at 2:06 AM on March 26, 2017

Response by poster: (I guess the idea is that when it appears to be 'on', that means it is doing its job of cutting power to everything for emergencies. When it appears to be 'off' it is not doing that job of cutting power.)
posted by lollusc at 2:08 AM on March 26, 2017 [1 favorite]

Okay, I understand that the up and down positions could be different for the RCD, but I've never seen a switch where red is on and green is off. I guess for the RCD green means off and safe to touch the wires and red means on and not safe to touch the wires. Weird, learn something new every day. Glad to see you figured it out.
posted by JackFlash at 7:23 AM on March 26, 2017

Don't know if it's the same/similar to what lollusc has, but here's one from Clipsal for illustration: The RCBM220/30.

You can see why that may be confusing, especially when you consider that, as lollusc said, switches in Australia (along with many other Commonwealth countries, & unlike the US/Canada) are almost always up=off, down=on.

The ones in my place are (I think) Hager, and the only indication they have tripped are (a) the lever moves just slightly from the on position, and (b) a small green/red indicator set deep behind a 2mm x 2mm window…
posted by Pinback at 4:43 PM on March 26, 2017