Ask MetaFilter questions tagged with electricity

where do these wires go?

crazylegs — Sat, 26 Dec 2009 07:03:06 -0800

I'm wiring NM-3 cable into a fuse box. Where do the wires go? I'm putting an NM-3 cable into a fuse box. There are four wires: bare, white, black, and red. I know the bare is ground, the white is neutral, and assume both the black and red are live. I know where the ground, and neutral go. The black is attached to a fuse, is the red just attached to another fuse? Note: this isn't a 240v circuit.

let there be light!

crazylegs — Sun, 06 Dec 2009 06:22:37 -0800

Help me re-wire a complicated old lamp. Yes, yes, I've done it again. Taken something apart that I can now not put back together. This is a lamp with a single bulb on top and three smaller bulbs further down. I tried to rewire it and made a big pop. Oops.
The small print: The switch for the upper light is separate, and not a problem. I need to rewire the part in between the three smaller bulbs. What I have is two wires coming down from the top bulb, two wires coming up from the power source, two wires coming out of each small bulb, and one wire coming out of the switch that controls the three smaller bulbs. Total of 11 wires. When I took it apart these were connected in three groups. I thought I kept track of how they were configured but obviously I was wrong. There is probably a diagram of this somewhere on the internet but I couldn't find it. Any directions to such a diagram, or instructions about how to configure these 11 wires into three groups so that everything works, would be greatly appreciated!

Speaker noise when metal USB plug touches my computer case and other electrical problems.

archagon — Sun, 01 Nov 2009 16:21:09 -0800

Speaker noise when metal USB plug touches my computer case and other electrical problems. I have an aluminum PC case. Whenever the metal USB plug from my external drive contacts the front, I get crackling from my speakers, which are connected to an external USB soundcard. (This crackling happens even if they're not connected to the actual output jack.) A few possibly related problems: my audio occasionally starts popping once every few minutes, and my USB devices sometimes play the "connected" sound in Windows even though they're already connected, as if they're briefly disconnecting.

My guess is that this has to do with the grounding, but I'm not sure exactly what to do. My case has a round grounding wire, but I don't know where to attach it, and fiddling with it didn't seem to have any effect. Suggestions?

It's not all Ben Franklyn and ENRON is it?

Anonymous — Wed, 21 Oct 2009 08:56:36 -0800

Tell me all you know about electricity markets. I am looking to learn as much as possible about electricity markets (specifically the UK/Europe) for an interview that I have coming up. I understand the technical aspects of the job that I am going for but I am a bit unsure about some of the Political Economic Social Technological (PEST) factors that are having an effect on the industry at the moment and I would like to have greater insight. There seems to be a whole raft of information about the long-term energy supply issues that the world will face in the next 30-50 years but there is not so much on how that will impact on the next 6 months to 5 years.

What is the strategy for utilties at the moment? Are there any regulations on the horizon that will impact on these companies? Is there anything else that I should consider?

*It's anon because a few people at my current employment know my username here*

Thanks

How much electricity do you use?

thewalrus — Wed, 14 Oct 2009 00:21:39 -0800

In the interests of science, please tell me how many kilowatt-hours (kWh) your house or apartment used last month and how much it uses in the middle of winter. If possible include variables like whether you use electric heat, air conditioning, electric or gas hot water heater, etc. The US DOE says the average American house uses 900 kWh a month. I'm trying to get a smaller but more personalized sample from metafilter users. kWh may also be marked as "units" on your electrical bill. I'm working on a design for some small and medium solar power setups and am trying to figure out whether the average person lives within the production capacity (budget $$$) of the total package of equipment.

If I can draw a broad generalization, mefi users tend to have a larger than usual number of computers and electronic gadgets, but may be more environmentally conscious than the average North American. This means that you may tend to avoid gratuitous use of laundry dryers and other power-sucking appliances. Please mention if this is true if you are telling me how much you used on your last power bill.

Kludgy home electronics melts pizzas

M.C. Lo-Carb! — Thu, 17 Sep 2009 12:05:31 -0800

How can I inexpensively stop my washing machine from melting my ice cubes without burning my house down? The outlets for my washer and dryer are on the same circuit as those for the appliances in the kitchen. My house is 60 years old, and is ungrounded, so to meet code requirements, the previous owner installed a GFCI unit in one of the kitchen outlets. All of the other kitchen outlets, including the one the refrigerator plugs into, are affected by this GFCI.

Unfortunately, when my washing machine switches from the rinse cycle to spin, something in that transition causes the GFCI to throw, which powers down the entire kitchen. This doesn't happen all the time, but about, say, 1 in 2 washes.

We've put up with this for 5 years now. A couple years ago, we bought a new washer -- no difference. This is very irritating, because we basically can't leave the washer running when we aren't at home, as we keep frozen bulk foods in the freezer and they will be ruined. We can't even run the washer when we go to bed!

So I'm wondering -- how dangerous would it be, really, if I just replaced the GFCI with a standard outlet until we sold the house? I'm guessing the GFCI is more aimed at keeping people from getting shocked if they drop an appliance in a sink, etc., like the one in the bathroom, yes? We don't really use electrical appliances near the kitchen sink.

Someday, we'll either have the system grounded, or go through the hassle of attaching the washer/dryer outlet to a different circuit, but in the meantime, would removing the GFCI really imperil us or our house?

Two bulbs, one switch

furtive — Mon, 07 Sep 2009 15:27:44 -0800

Can I wire two light switches into one switch? I have two light switches in one plate. The left one lights the bathroom above the mirror, the right one lights above the toilet/shower. We'd like to make this one single switch since we find there is no need to have separate switches.

Is it as simple as putting both sets of wires into one switch? What should I be checking first? They are on the same fuse. Can you buy a plate that's double wide but only accommodates one switch?

My level of skill: I once cooked a hot dog using two nails attached to an old electrical plug, and managed to short the grade four classroom at the same time.

Identify ceiling fixture wiring

stupidsexyFlanders — Sat, 05 Sep 2009 15:03:38 -0800

Replacing ceiling fixture. Removed old fixture. Help me identify the wiring so I can wire the new one? Very old house, very old wiring. Third floor ceiling (attic is above). Removed old fixture, there was no box, so I tore out a little ceiling to find a joist to nail a new box to.

Now to wire the new fixture. Hanging down are three wires, with one of them actually jacketing two separate wires (individually insulated, but in the same outer insulation). These 2 were twisted together as one wire and connected via wire nut to the old fixture.

So if you call that one wire, then there's that, and then two separate wires. They all have an outer cloth kind of insulation, then inside that the actual wire(s) are insulated with something that was very brittle and crumbled where I touched it. So I'm going to cover everything with heatshrink tubing before I start manipulating it & stripping it and connecting it and folding it into the box, but the question:

how do I figure out which of these 3 (4) wires goes to black on the new fixture, and which to white? Could one be a ground? Do I have to buy a tester thing?

The fixture is controlled by one switch only.

Electronic Catan

jasondigitized — Fri, 04 Sep 2009 05:37:32 -0800

I want to create a customized Settlers of Catan board. For the purposes of this question, it could also be a custom Monopoly board. I want the pieces ( cities / hotels ) to light up when they are placed on the board. I know I would put LED's in each piece, but besides that, I am not sure if or how I could power up the LED's. I am not an electrical engineer, but magnets, watch batteries or inductive charging sound good to me. Help me make an awesome electronic board game!

My air conditioner causes my room to have brown-outs. Can I fix this?

SuperNova — Wed, 19 Aug 2009 12:30:07 -0800

When my window-unit air conditioner revs its motor, my overhead light dims... then seriously brightens up when the AC slows down. It's annoying. Is there anything I can do? I just moved into an older (1950s-era, I think) house. My room is cooled by a window-unit AC, which has been running close to full blast all the time lately (it's hot as hell right now). Intermittently, the lights in my room will dim as I hear the AC crank up, only to blink back to full brightness when the AC slows down a few minutes later.

I've thought about replacing the incandescent bulbs with CFLs, which would at least reduce the power load, but since I know CFLs aren't supposed to be great at handling irregular voltage, I'm not sure that wouldn't make things worse. (I did read this potentially-relevant question, but I don't think it helps me in my situation.)

Right now, I think of this mainly as an annoyance... BUT, I'm also worried about other issues down the line. I have my laptop plugged into a power strip ("surge protector" of unknown efficacy) but a desk fan I just plugged into the same strip seemed to slow down when the AC cranked up, which makes me think my computer (and, when I hook it up, my year-old TV) is being subjected to the same kind of local brownout... and that can't be good, right?

Worth noting, perhaps, is that the AC looks pretty old, so maybe I could convince the landlord to replace it with a more efficient (?) modern unit. But the landlord had to be essentially forced into doing basic maintenance, so I don't see him doing anything about the AC unless it dies (and AC murder isn't an option since, again, it's hot).

What can I do?

Help me repair a few jimmied EXIT signs!

JaiMahodara — Thu, 13 Aug 2009 11:30:01 -0800

Do 2 or 4 bulbs in a regulation exit sign light up automatically? Ie, are the two outer small bulbs automatic and the two inner 120V/4W jobs there as backup? I'm not an electrician and retailers don't have much (anything) in the way of repair guides..only product order forms. These are exit signs in a theater that have been disabled for art's sake, but which by law need to at least be able to remain lit. It also looks like the button on the bottom of the box used to have a plastic mechanism that let the light click and stay on--now the two outer lights only remains lit if you hold the button in.

My extended questions are:

Is my diagnosis of the disabled plastic accurate -> Do they normally click on and off using the button on the bottom?

Should I be gunning for all four lights turning on, or are the inner two routed to the battery for when the outer lights fail? (I could unscrew and replace the inner 120V's but the outer 2 look like they come as part of the system.)

Argh blargh monopolies

showbiz_liz — Wed, 12 Aug 2009 09:16:30 -0800

My new rented house used to be a duplex, and it still has two electricity meters. Do we really have to pay two bills every month because of this? Five friends and I have rented a large house to live in. Our lease just started, and we are in the process of getting the utilities set up so we can move in.

The house is a renovated duplex, which is why it's so huge. The renovation is so recent that it was still going on when we signed the lease last winter.

Our landlord told us that for most of the utilities, the house still had two meters in place, so we'd need to let the various companies know.

I was in charge of setting up water, and after lots of back and forth with the landlord it came out that, really, it was only necessary to turn on one of the meters. I got it all set up, and it was fine.

My roommate in charge of electricity, however, was told- either by the electricity company or the landlord, or both, I'm not sure- that we had to turn both meters on. And then the power company charged her two separate activation fees, for a total of $300!

This really seems sketch to me. Why on earth should we have to pay twice as much in electricity bills just because of what the house USED to be like? Is this issue something that should have been corrected during the renovation, or what? Is it legal for them to charge us twice, and is there any way around it? I.e.- if we just had one electricity meter turned on, would the whole house still GET electricity?

Only one of us is in town with the house yet, which only makes this all more complicated.

Shutting off the Electricity to the Solenoid Valve

scunning — Sat, 08 Aug 2009 11:31:37 -0800

One of the zones in my outdoor sprinkler isn't working, caused it appears by a malfunctioning solenoid valve. I spent the morning learning how to inspect, repair and/or replace it, and I'm about to do so, but I am unsure as to whether electricity is running to it. How can I know? On the house's main circuit breaker control panel is a switch marked for the sprinkler system, and when I turn it off, the LCD goes blank on the sprinkler box. But, what I am unsure of is whether the only electricity going to the solenoid valve is coming from the sprinkler box, or if it is possible that when I turned off the electricity to the sprinkler box, that the solenoid valve is still hot. I don't want to start digging up the valve to repair it until I know for sure that the electricity is off, but how do I do that practically, or is the only electricity it gets from the sprinkler box?

Alternatives to running a ground wire?

nitsuj — Thu, 30 Jul 2009 11:39:17 -0800

Will a surge protector or UPS plugged into an ungrounded outlet do anything to protect my electronics in the event of a power surge? There are conflicting answers to this question online.

Is there anything I can plug my computer/tv/electronics in to to protect them from power surges on an ungrounded outlet, or is the only solution to actually ground the outlet in question?

Light switch making popping noise.

feathermeat — Wed, 01 Jul 2009 06:33:45 -0800

Calling all MeFi electricians: why does my light switch make a popping noise, and will it kill me? I have a light switch in my kitchen that intermittently makes a small popping noise when turned on or off. Usually it'll happen a few times in a row, and then not happen again for several weeks. I have not experienced any flickering/dimming of the light in questions and I have not seen any sparks. There have been a few times when it's happened and I have smelled a little bit of ozone (at least I think it's ozone). I have tried to google this, and it seems like the answers range from "this is going to start a fire, call an electrician immediately" to "the switch is going to stop working eventually, but it's not a safety hazard, so replace it whenever." I don't mind replacing the switch if that is what's needed, but money is tight enough so that I really, REALLY don't want to call an electrician if this is not a big deal.

What are the best options to measure the electricity usage of common area in a condo?

coust — Tue, 16 Jun 2009 10:32:47 -0800

What are the best options to measure the electricity usage of common area in a condo? We installed 2 electric heaters in the crawl space below the house to help reduce humidity and alleviate problems we had with fungus forming on the wooden beams supporting the house. The electrician who did this hooked them up to the circuit of the owner of the 1st floor. Since this benefits all tenants we'd like to share the cost of this electricity. Which bring us to the problem of measuring it. We've contacted the power company about installing a new meter and then having an electrician hook the heaters to the new meter but I feel the cost of really too high (~1400 CAD total) compared to what we'll be measuring and splitting.

So does anybody knows of a better (and cheaper) way to do this?

The heaters aren't plugged on a socket so I can't use a device like a kill-a-watt. We'd also like the device to not lose track of power usage after a power outage. And it's a bonus if I don't have to go in the crawl space every 6 months to take a reading (but I'm willing to do it).

window fan + lightning storm - will sparks fly?

MesoFilter — Thu, 11 Jun 2009 22:48:31 -0800

Is it okay to use a window fan during a thunderstorm? I leave my window fans running all the time, even during thunderstorms. Frequently I'm not home and not even really aware that a storm will be coming, or it happens while I'm sleeping.

I'm on the 6h floor of a 6 story apartment building. Do I have anything to worry about with window fans & thunder storms?

What do I need if I want to put out a newsletter but I don't have any infrastructure?

croutonsupafreak — Sat, 06 Jun 2009 23:34:38 -0800

What would it take to print a few thousand sheets of paper every other day while completely off the grid? I will have no access to any electricity or supplies, except those that I bring with me. I've got a laptop and a camera. I need a printer.

Will a consumer-grade laser printer with a new toner cartridge be sufficient? Is there a better choice for making lots of copies? How do I power the printer and laptop for a few hours each day, and keep the camera charged? Do I need a full-fledged generator for this? Is a battery a better choice? How much is this sort of thing going to cost? Anything else I should consider?

In the dark about my light bulbs

emumimic — Tue, 02 Jun 2009 07:16:31 -0800

Why do the glass parts of my light bulbs keep separating from the metal? New homeowner here. So far, in less than a month, three burnt out light bulbs have just slid out of the sockets, leaving behind the threaded metal part. I know about the potato trick, but there's no broken glass left behind. I found this question that seems to describe my problem, and tried this solution (didn't work, although it seemed promising at first), and I've already broken two fixtures trying to get these bulbs out (sigh).

At this point, I'm less concerned about how to fix what's already happened, and more interested in WHY it's happening so that I can keep it from happening again. It may be noteworthy that once I can get the metal part to twist out, a powder comes out (like a corroded battery). Is it the wiring? The fixtures (the house is about 30 years old, and the two fixtures I've had problems with (so far) seem to be original or nearly so)? Just old bulbs? Would it help to change them all right now?

Aside from the inconvenience, it ruins phone sex

notashroom — Wed, 13 May 2009 08:33:42 -0800

What can I do to help a friend with interference issues causing phone problems in her house? My friend has virtually no cell reception inside her house, so she still has a landline. She has two 2.4GHz cordless phones, neither of which works in the southwest corner of the house. They can initiate and receive calls, but there is very loud static that prevents either party from hearing.

That corner of the house (her bedroom and bath) is where the house's power line enters. I'm guessing this may be the origin of the interference, but I'm no engineer. She's tried various locations for the phone bases, with no appreciable difference (both within the room and in other upstairs rooms). The static dissipates immediately after leaving the bedroom, just a foot or two into the hallway and it's gone.

Other info, in case it's relevant:
- Under the bedroom is the garage, which does have a remote door opener.
- The computer is more than 20 feet away. There is no wireless.
- She has Dish Network. I don't remember where the satellite is, but it is possible that it is in direct proximity to the bedroom.
- In the bedroom within 24" of the wall corner where the power line enters (but approx. 4' below), are an LCD TV, Dish box, and iPod docking station.
- The building in question is a single-family house with over 30' of clearance on each side from neighbors. There is no nearby power substation or anything.

What, if anything, can I do to help her be able to use her phone in her bedroom?

Extending digital camera battery life

devnull — Wed, 13 May 2009 08:24:24 -0800

Should I keep my camera turned on to save electricity? I have a newish compact digital camera with a 3x optical zoom lens. It's small enough that I actually carry it around and use it.

When I turn the camera on, the lens extends and the screen comes on.

Sometimes when I take a few photos I worry that leaving the camera switched on is wasting electricity and will wear the battery down.

But turning off the camera will cause the lens to enter the body again, using electricity. When I want to take a photo again, the lens must extend again to get back to where I was.

How long could a camera be left on before the energy from retracting and extending the lens, as well as the energy to run the camera, is more than the energy to turn the camera off and on again?

(I realise this question is camera specific, but I'm looking for a rule of thumb - thanks!)

Will this TV kill me redux

yarrow — Sat, 02 May 2009 11:06:33 -0800

How dangerous is it to take apart an old TV if it has been unplugged for many months? I have an old TV - 19" Samsung from the early 80s - that I would like to disassemble in order to use the shell for an art-type project. I've seen this question and warnings elsewhere on the internet that digging around inside a CRT TV can be pretty dangerous. This TV has been unplugged since last October, so for about 7 months. Is that long enough to obviate the worry about voltage issues in the CRT?

What DC voltage does an average LCD monitor use?

leafxor — Fri, 27 Mar 2009 17:41:54 -0800

What DC voltage does an average LCD monitor use? I'm trying to power an LCD monitor from a 12-volt battery, but I don't want to waste efficiency by inverting it to a 120-volt AC, then letting the monitor turn it back into DC current again.

Too good a discount?

XMLicious — Mon, 16 Mar 2009 21:06:06 -0800

Construction electrical: why is this service panel on sale at more than an 80% discount? Elsewhere it indicates the original price to be around US$1500 but the current price is almost down to $200. There are several other panel boards marked as "clearance" on the Grainger Industrial web site that have similar massive discounts to their prices, yet there are also many non-sale ones that are near the original price - the original price being what several books have lead me to expect as standard pricing.

I'm not considering buying it, I simply came across this in the course of research while fantasizing about building a dream house. I'm curious as to whether this is really a clearance sale of the sort a retail outfit might have or if there's a more sinister caveat emptor reason for the price, like if the panel is useless in most jurisdictions now due to a recent code change or something.

TV on all the time

Epsilon-minus semi moron — Sun, 15 Mar 2009 11:48:49 -0800

Craigslist HD TV deal..it was $25. The rub being it "doesn't always turn on". The first week it was fine. Then it started not turning on until later in the evening. The boyfriend (possibly) diagnosed the problem and will attempt to fix it when it becomes absolutely necessary. However, until then we are leaving it on all the time. We are keeping it on one of the video channels. Is there a chance that doing this(keeping it on a channel that is black/silent versus one with action/noise) uses less electricity? Thank you!