SoylentNews is people
SoylentNews
Our power went down yesterday afternoon (December 12). The utility posted a message on their 1-800 number with expected repair time (a few hours later), but no explanation except that ~2000 customers were affected in our suburban area (Northeast USA).
Here's the weird bit -- LED bulbs stayed on, at reduced brightness. I got out a meter and measured 16 VAC in the house. This was enough to make useful light from "dimmable" LED bulbs (happened to be GE brand). After it got dark, we could also see that incandescent bulbs were giving off a faint reddish glow.
16VAC was also enough to keep a Netgear home router/Wi-Fi box going, it must have a switcher in the wall wart that accepts a really wide input voltage range?
Called a friend on the other side of the country who is an EE (with hardware background). He didn't have a good explanation, but suggested that in the process of bringing the grid back up there might be some big voltage swings--recommended unplugging everything we could. Went out to dinner and all was restored when we got home (no damage).
He also told a story from a rural area (near CA-Nevada border) where there was a power failure that upset the normally-balanced split phase -- instead of ~120V on both sides of neutral, the power went to 80V on one side and 160V on the other side of neutral. Equipment on the high voltage side failed due to extended over-voltage, seems that surge suppressors won't deal with this much energy.
Anyone? How does the grid fail-soft?
(Score: 4, Interesting) by ledow on Tuesday December 15 2015, @10:32AM
I bought my girlfriend an electric kiln. This is a 32A monster thing that weighs a ton that you plug into a commando connector (the building site connectors - 220V 32A in my case, which needs a slightly-larger-than-normal version). I bought it second-hand because new they cost more than anything I've ever bought in my life.
We paid an electrician to put an RCD and external commando connector on the side of the house in the alleyway (the idea being that we could use it for other things, maybe even an electric car someday). He cabled it all in, said it worked, certified it, and left.
When I plugged in the kiln, I hadn't had a chance to test it previously. 32A raw connections are rare at 220V in domestic scenarios! We plugged it in, it lit up, but that's all it did. Not action at all, no heat.
I ordered the circuit diagrams from the manufacturer, I dug out all my electrical knowledge, took the thing apart and COULD NOT for the life of me see a problem.
So I bought some adaptors and plugged other things into the 32A commando connector. Nothing. The extension lead lights would light up but they wouldn't power. When I voltage-tested, I got about 20v. Extremely weird.
I had wanted to avoid exposing myself to the kinds of power in that box and playing with fuseboxes, but eventually I just switched the house electric off, tested I was safe, and opened up the box on the side of the house.
I found that he had wired the neutral and live into the huge power switch.
He'd wired the commando connector to Live and Neutral terminals provided below the switch.
But he'd only wired the live in between the two. The neutral was completely disconnected and two separate wires coming in and out.
So much for electrical certification!
When I wired the neutral in properly, it all just worked, kiln included, and has worked for over a year now.
Check your neutrals. I bet you have a similar situation.
(Score: 2) by FatPhil on Tuesday December 15 2015, @12:32PM
Absolutely. However, out of paranoia, check everything. The first thing I did when I started house-hunting was to buy a simple mains socket tester. Plug it in, and a pattern of leds lights up telling you what's good and what's wrong. This was after nearly electrocuting myself on some small consumer electronics device on the first day in my previous place - there was god-knows-what coming out of the *earth* connector. Paid a professional to fix that, I'm a wuss.
> 32A raw connections are rare at 220V in domestic scenarios!
Yeah. It's strange that you're not using 3-phase (or 2/3 of 3-phase)? My sauna stove is available in 1-phase 230V configuration at 40A, but I have a 3-phase configuration at 400V and much lower current per phase. Everyone I know (who has a sauna) has the 3-phase install, but that's because in this part of the world saunas are designed in at building/renovation time, not afterthoughts.
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 0) by Anonymous Coward on Tuesday December 15 2015, @01:02PM
Those little detectors do not detect hot ground and neutral (sometime happens to defeat the test, I have read). You can use a voltage sensing pen for that.
(Score: 2) by Runaway1956 on Tuesday December 15 2015, @04:33PM
Depending on what part of the country you are in, the electric company may make 3-phase "unavailable" in residential areas. Where I live, there is no 3-phase to the homes. Of course, there is 3-phase at the highway, and if I were to beg and plead, they would come out, run the third wire down the county road, and hook it up to my meter loop. The fee would be as much as several month's electric bills. If I lived in town, or if I lived at the other end of the property, the 3-phase would be a hell of a lot closer, and cheaper, but still not cheap. Different states have different laws, of course. When I was a kid, my dad wanted 3-phase 480 volt, he just picked up the phone, and it was hooked up within a couple days, no problem, no big bill.
(Score: 0) by Anonymous Coward on Tuesday December 15 2015, @01:47PM
I don't know about where you live (you didn't say) but in the USA the Neutral and Ground wires are to be connected at all times and never go through a switch. Those wires should go uninterrupted all the way back to the bus bars in the main circuit panel, the only exception being with a GFCI or AFCI breaker where the Neutral passes through the breaker as the device needs to monitor the load on that wire at the same time as the Hot.
(Score: 0) by Anonymous Coward on Tuesday December 15 2015, @03:23PM
Devices connected to the load side of a GFCI receptacle would be another situation where the neutral is not directly connected to ground at the panel.