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Need... More... Power...
MikeDawg writes "After dealing with the headache of never having enough electrical outlets, not having a cable TV coaxial, not having a telephone hookup in the right places of my apartment, I found this article at CNN. It is nice to see that college dorm rooms are getting filled with outlets to provide students with enough hook-ups with for all their electronics. My question to you (renters/dorm-room dwellers) is does your dorm room or apartment have enough outlets, whether it be electrical, cable, telephone, or anything else you may need? What do you do in a situation like this? Do you load up each socket with a 10+ port power strip (or battery backup as it may be) and pray that you don't knock-out the circuit everytime you start burning a CD?"
One of the reasons they're doing this is that students often tend to use multiple extensions on a single outlet, which is the second leading cause of fire deaths, according to this.
In fact, the recent Moscow dorm fire that killed dozens and injured hundreds more was caused by such a fire, by a computer science student with dozens of electrical devices in his dorm. I suppose universities don't want such a thing to happen here.
http://seattletimes.nwsource.com/html/nationworld/ 2001802164_dormfire27.html
I have similar problems when I host large LAN parties (IE, over 40 people at a hall). What I have found is that you can work everything out pretty well, and it will reduce problems. In Canada, the standard rating for an electrical circuit is a maximum of 10 amps. When you increase resistance in parallel, you increase the overall amperage. So, you have to watch how many computers you plug into a single circuit. It doesn't matter if it's a new SOCKET, you have to be certain that it's another CIRCUIT. In the US of A, the standard rating is 15 amps (or so I've heard) and so you can run a few more computers. Here in Canada, I find the magic number is 7 computers (that's a random survey of computers, and LANners like to have 400 watt PSUs and tricked out boxes with cold cathodes and the like). I hope that helps. :D
Canadian Cynic, canadian politics is less boring than you
well.. usb kind of does this.
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world was created 5 seconds before this post as it is.
...but hopefully the colleges are putting a little thought into their designs for the dorms. While it's true that outlets are usually in short supply, you can still be up an electrical creek without a paddle if all the outlets are on the same (underpowered) circuit.
A lot of apartments suffer from this problem as well no matter what their age... I have lived in an apartment that was over 20 years old, and it had a total of three ten-amp circuits for the entire place (not counting the circuits for the appliances which are pretty much dedicated). This was not exactly optimal for supporting five PCs and their peripherals along with a SUN Ultra 450. I've lived in newer (5 years old or so) apartments that had the exact same problem.
It's my opinion that the best thing you can do is go to Radio Shack and invest in one of those Circuit Detectives. Use that to determine what outlets correspond to which breaker, and how much power you have through that breaker (the ratings are printed on their for your sanity). Once you have that figured out you can begin learning the fine art of load-balancing on your outlets. "Let's see, I have 2 amps for my PS2 here on circuit A, and 3 amps for my TV on circuit B, and 2 amps for my PC on circuit A...."
This summer we decided that having a 1' deep cable pile over half of my bedroom wasn't a wise idea. So we renovated the old guest bedroom into an office for me. We quickly came to the conclusion that my bedroom was about "-" that close to an electrical fire as-is, so we made sure that there was enough E running to the room for peak power demand of all the systems.
We currently have one 15-amp circuit (120) and three 20-amp (120) circuits run in here. That's about 9 kW of power if I need it. I strongly recommend with all computing projects that you never, ever, ever scrimp on your electrical budget - it will serve you well.
Oh yeah, and major points for adding a battery backup - they own.
-Jordan
let's make some REAL calculations....
Computer - From 350 to 550 watts. monitor? flat panel LCD - 20 watts. a 17 -19 inch regualr monitor? 170-200 watts. Speakers? from 30 watts to 200 watts or more.. PDA 20 watts charging.. usb hub 15 watts, small 100 base switch and/or your smc firewall to hide and protect 60 watts.
now that is just a base computer. no printer (80 watts for a cheap inkjet 300 watts for a small laser printer)
Let's add a cheap fridge.. a $59.00 cube fridge= 500 watts. almost every dorm room has one. as the crap 6 can fridge from think-geek is worthless for a dorm.
my 9 inch TV here uses 160 watts on it's own.. and then you mention a stereo... maybe a cheapie boom-box will use 300 watts, a regular stereo uses from 500 watts to 3,000 watts depending on equipment, amp power, speaker load, etc....
and your 300 watt misc load... is a bit low...
anyways.. being conservative on the above figures.. I get 2070 watts drawn.. at 120 volts (average US voltage in the wall socket.)
I get 17.25 amps... enough to completely hose and set fire to a cheapie power strip. (if you did not pay $50.00 to $100.00 for your power strip... it's a cheapie.)
that will strain a 20 amp breaker (inrush current will be much greater than 20 amps.. more like 35 amps if you were to turn everything on at once.)
and it is rare that contractors wired the place correctly with 12 gague copper and 20 amp breakers. most contractors cheap out and run 14 gague and use 15 amp breakers... betting that your dorm room is on one breaker for it's outlets and one for lighting, ahared with others..
and from what I have found myself in the 80's in college, and my nephews now in college... this is true. each room is given 15 amps typically for 2 people to share. the above list is not a workable load and therefore usually the stereo get's chucked and they use the computer as a stereo.
god help the students if they are geeks and have 2 computers.
Do not look at laser with remaining good eye.
holy crap you are giving him bad advice.
Sure you can get the type that goes in the breaker box (a good idea in fact), but that doesn't stop the same level of surgers as the power strip will.
so your lack of knowledge is dooming this guy to have sub-standard wiring. Very Nice of you.
most quality whole house surge supressors are at least 20 times more effective than the crap you can buy even for $100.00 as a plug in strip.
My IsoBar whole house supressor with replaceable surge and filter modues was not the top of the line for whole house and still had ratings that were far higher than even the "audiophile" quality power strips.
plus it's reaction time is at least 300% better so the power spikes dont get past it... unlike all power strips as they lack a solid ground to drop the surge to... they can be fast but they dont have a ground that is effective for dropping a 4000 volt spike.
I really feel for people buiulding a house and taking advice from amateurs that really dont know what they are talking about.
USE WHOLE HOUSE supression, period. if you have a home theatre, add a second whole house supressor and noise filter if you really think you need it.
A properly designed electrical system in the home with the correct surge equipment at the front end (the electrical box) solves all these problems. from surges in the house from flipping on grandma's 40 year old stand mixer to nasty surges from the factory down the street.
Do not look at laser with remaining good eye.
None of these produce any usable power of course.
"Studies have shown that people who eat peanuts live longer than those who do not eat."
Hi! Did you ever hear about .... OTHER COUNTRIES??? Oh I don't know, where they use 220 volts??????
Sounds like they had a weed grow :-)
Bush and Blair ate my sig!
In practice you'd like a power bus fed by some big central PS that doesn't depend on the computer. This PS would provide for standby power to peripherals, like the ATX standard. Compliant peripherals would take a trickle of power from the bus during "sleep", and wake up (turn on their main power supply, reset and boot) on some electrical command. Some other command, or a sustained period of inactivity, would set them back to the sleep state.
This is pretty much what many cars have today, using the Controller Area Network (CAN) bus. CAN modules "sleep", some with their RAM powered on and all with their comm chips running, on less than a milliamp. The speed is not up to computer specs (0.5 mbit/sec or so), but the techniques could easily be adapted to something like FireWire if the will existed or one manufacturer had the pull to create a de-facto standard. With something like this you could have a "power strip" like a laptop brick, putting out 12-14 VDC for a host of peripherals and maybe the computer as well. You might not get rid of all the wires (though a combined power/data bus could do that too), but you'd certainly get rid of all the wall-warts. It would make backup pretty trivial, too (just hook in a deep-cycle battery). Who wouldn't want that?
Time is Nature's way of keeping everything from happening at once... the bitch.
No, actually, he's/you're wrong. My Antec power supply is rated at 400 watts, and running two optical drives, raid 5, an additional hard drive, and over a dozen fans, and my line load at the outlet is no where near 400 watts last time I checked. Has been over a year since I checked, but I haven't changed the setup since then either.
This also has been covered in articles where cost of running a computer has been discussed, and is also covered on some electrical utility web sites. Electrical consumption is rarely even close to what the power supply is rated at. Usually it is much less, often less than half.
This also often applies to stereos and other electrical items.
Just do some simple math and you can avoid overloading a circuit.
1) Determine the rating of the circuit -- I imagine each dorm room will have one circuit. (Maybe two)
2) Determine which outlets go to which circuits. If outlets are close together, then they are probably on the same circuit.
3) Calculate the amps of everything you are plugging into the circuit.
4) Add them all up.
5) If they are close to or over the amp rating for the circuit, then you have a problem, and you will have to unplug stuff.
Important points to remember:
* Don't forget to check the rating on any power strips that you use! Most are rated at 15 amps, which is probably the same as the circuit you are plugging into.
* Circuit breakers can momentarily handle more than their rated amps. ie: it might be able to handle 17 amps for, say, 30 seconds before tripping. The higher the amps, the faster the trip. A direct short will (er, should) instantly trip the breaker.
* Not everything has the amps listed -- some devices only list the watts. You can calculate the amps by dividing the watts by the voltage. ie: your 400 watt computer running on 120 volts will have a max amps of 3.33.
* If you are in a situation where you have two circuits near your computer, and you overload one, keep this in mind: It is generally a Bad Idea to plug some peripherals into one outlet and others into another. Subtle differences in voltage and phase can lead to a net difference in voltage between your equipment and lead to permanent damage.
* This may be unfounded (someone correct me if I am wrong), but I always think that it is more dangerous to overload a power-strip than an outlet--meaning that I trust the circuit breaker in the closet more so than I trust the power strip.
I hope this helps. If you read this and go kill yourself, it's your own damn fault. Use at your own risk. Use common sense, and remember that this IS slashdot.
— darco
have you considered using a bicycle generator? i.e where you have to pedal for 5 hours a week to charge up a battery which can supply enough power for a TV for an hour or so?
I've thought of that before. You know, it's a great idea for a few reasons:
I do have to wonder about how bad this dorm room power crisis really is. Let's consider appliances with realistic maximum power consumptions:
Note that many of these loads are intermittent or mutually exclusive. Most laser printers only pull any amount of power when the printer is actually fusing a page. The boom box probably won't be playing loudly at the same time as the computer speakers. And, unless you like to leave the door open, the beer fridge's compressor should be off most of the time.
And some of these appliances will become duplicates in a shared dorm room, so the realistic likelihood of them being on at once is small.
1830 watts is the total power consumption for the list of appliances above. In my jurisdiction, commercial buildings (including University residences) have one outlet per 1500W circuit. Most circuit breakers are thermal (takes time to heat up a bimetallic strip in the breaker) and therefore act like slow-blow fuses. And unless you're printing a massive pile of course notes while playing the boom box and computer speakers loudly and doing it with the beer fridge door jammed open, the loads are probably going to be too transient to trip the breaker. So you may have a whole load of power bars plugged into that one outlet, but in reality, it's likely to be perfectly fine.
On the other hand, dorm rooms are small. It's in the students' best interests - forget power consumption - to slim things down:
Noting that this scheme is merely a common-sense approach to giving you more space in your dorm room (and making moving at the end of the year that much less painful), your maximum consumption will only be about 1260 watts. Which means that if you've got a circuit, you're fine.
I'd suggest to universities that they point out in their residence brochures something along the lines of "Moving into and out of residence can be unpleasant. For that reason, we suggest that students attempt to travel as lightly as possible. LCD monitors and video cards with TV inputs will save you space by avoiding having to carry around bulky CRT displays." Maybe offer a small rebate to students who use an LCD monitor and TV-in video card to replace a CRT-based monitor and TV set.
Fire and Meat. Yummy.
A properly designed electrical system in the home with the correct surge equipment at the front end (the electrical box) solves all these problems. from surges in the house from flipping on grandma's 40 year old stand mixer to nasty surges from the factory down the street.
Agreed. But there's still more to it than that.
Surge suppressors on the power entry, just after the main switch. *Large* breaker box.
And if you're building the house - or doing extensive work involving the removal of lots of drywall anyway - rewire the whole house. Build it to commercial specs, even if your residential requirements are lighter.
My suggestion is to use conduit for all wiring, and make sure that you put in extra conduit all over the place so that you can fish network and phone cables into any room as required. Put each duplex outlet on a separate 15A circuit (20A circuits are against code in residences in most jurisdictions). GFI outlets aren't just for bathrooms - they're not very expensive, so put them everywhere - they can save your life and your electronics from damage (say your stereo has a ground leak and you connect it to your computer). And make sure that you have an outlet at least every 10 feet in every room.
While you're doing all that, of course, you should be installing a residential sprinkler system. (Why? Sprinklers massively improve the fire safety of a house or commercial building. And it's a lot easier to clean up water damage than fire damage.) The reduction in your insurance rates over a few years might well pay for your entire renovation costs, and talk to your insurance company about the fact that the building is wired to commercial standards for another potential savings.
Other things to consider: While you've got the house apart, insulate the piss out of it, whether you're in a warm or cold climate.
You might also want to install a gray water system for the toilets. It's against code in my jurisdiction, but I don't really care because it's a good idea. The premise is simple: my toilet is almost 50 years old. It's not one of those stupid "water-efficient" toilets that takes 6 flushes to get rid of dark matter. And I don't like urinating in perfectly clean water - there's no point. So I put a 55 gallon drum in the basement. The bathtub U-trap (unscrew the washout nipple and find a piece of pipe of the same thread, make sure you still have a bend in the hose for a three-way U-trap) and washing machine now drain into the barrel. Using bleach in a cotton white cycle not only keeps your shirts blindingly white, but also keeps algae out of the barrel. Near the top of the barrel is an overflow pipe which takes excess stored water to the drain. A burglar alarm magnetic switch on the toilet's float now controls a relay which turns on a small pump. Gray water is pumped through a small hose up into the toilet tank, using a fountain pump with 15 feet of head.
Since I live in a cold climate and like hot showers, not only am I reclaiming the water, but I'm also reclaiming the heat. The water in the barrel cools down slowly, releasing its heat into the house. Saves me over $200 a year in heat and water costs.
A fringe benefit is that warm soapy water in the toilet dissolves stuff better than cold tap water, so the toilet doesn't need to be cleaned as often.
Fire and Meat. Yummy.
A 13 amp extension cord is usually 16-gauge, sometimes 14-gauge for the longer ones.
19 amps running through 16-gauge wire (4.094 ohms per 1000') converts about 1.48 watts per foot to heat.
You'd have to run this extension cord through some amazingly perfect thermal insulation (carpeting won't do it) before anything could get to flashpoint.
Standard amperage limits are based off acceptable voltage drops, not heating.
In my first dorm there were 5 outlets, 1 of which was ungrounded (above a mirror). We were allowed hair dryers,
Heh... Note that those ungrounded outlets built into bathroom light fixtures are normally for electric razors only.
What's different about them?
When they say "RAZOR ONLY" beside the outlet, the outlet is usually on a small 1:1 power transformer. It's called an isolation transformer, and in those applications, they're usually only built to handle something under about 50W. Don't plug a hair dryer into it!
What does it do?
Ordinary outlets have a "hot" side and a neutral side. The neutral side is tied directly to ground at the distribution transformer and usually (depends on local electrical codes) at the fuse box. The hot side is connected to a winding on the distribution transformer which is putting out 120V with respect to ground. The power is then referenced to ground - usually to a cold water pipe which comes directly into the building through the earth.
Outlets also have a wide blade and a narrow blade. The wide blade is supposed to be connected to neutral, the narrow blade is supposed to be connected to hot.
Theoretically, you should be able to touch the wide prong and the ground (round prong) at the same time without getting a shock. The whole point of this is to allow you to accidentally touch the large part of a light socket base without getting a shock. Back in the day, lots of radios and TV sets used a "hot chassis" which was tied directly to one side of the power line - this should have been the neutral. (Most of them also predate polarized power cords, so depending on which way you had it plugged in, you had a 50% chance of the chassis being at 120V or neutral with respect to ground. Be careful!)
The isolation transformer removes that reference to ground, the potential difference exists only between the prongs of the outlet. This is good if you accidentally drop your electric razor into a sink full of water, because there will be no ground current through you - the only current would be from one wet point within the razor to another wet point within the razor.
Isolation transformers are a very important safety feature. Personally, I like them better than ground fault interruptors. The biggest problem with isolation transformers is that making one which will handle the current of a hair dryer or other large (power-wise) appliance requires a lot of heavy iron laminates and copper (expensive).
Fire and Meat. Yummy.
In the US, three phase installations tend to be 120/208 wye connected for office and light industrial and 460 delta connected for the heavier stuff. In Sweden, virtually all houses have three phase delivery, 220/390.
There were some two phase systems in the early days of the electric power industry, typically these are where you need three conductors and where on conductor is at ground potential. The turbo-electric plant on the Lexington and Saratoga (CVA-2 and CVA-3) were two phase since the hull served as the grounded conductor.
As for frequency, the US standardized on 60 Hz as a reaction to Europe standardizing on 50 Hz, although Southern California Edison didn't make the switch until 1947/48. Some communities had 25 Hz power, and one had 133 Hz. DC was available in some cities until very recently. Homes on windmills in the 30's and 40's usually had 32V power which was also used by the majority of US RR passenger cars.
A Shadeless room is a brighter room.
Standard construction in Thailand, where I live, has one [1] two[2]-holed electrical outlet per room, right next to the light switch by the door. Lots and lots of extension cords. In our bedroom the previous tenant had an air conditioner; we spliced the leftover power wires to an extension cord to create an outlet on that side of the room. Unless you have an electrician install the wiring, and watch him carefully, nothing is grounded, even if it's got three holes.
Well, mine does have _enough_ of them...but they're almost all _on the wrong side_. (The side with lots of outlets, including the cable TV feed and all the phone jacks, is the one which hosts the sofa and the lamps, while the one with all the computer and A/V hardware that so desperately wants to be fed power and bits has a measly two wall plates for power. Due to the odd geometry of the place, reversing the furniture arrangement would make it impossible to walk.)
I solve it by running long cables across the room, held above head height by wrapping them around the rafters (it's a loft).