15 or 20 Amp

[xrongor]

glad u said it so i didnt have to.

15A is plenty. in fact a 15 might be better. it will blow faster than the 20 if something does go wrong.

randy

[BinaryBillTheSailor]

Good grief, did you read what I wrote? Obviously you did not. You probably don't listen to anybody, which is why you end up posting ignorant things on usenet. I did not say to look at the labels on the machines. I said to look in the manuals or check with the manufacturer for the minimum required power for installation. I just recently had to look up an HP4050 laser printer, and HP says it requires

8 amps for proper installation and operation. Obviously it doesn't draw nearly that much 24/7, but that's what the company that designed and built it says. You can get similar INSTALLATION SPECS for the monitor and computer.

Incorrect, and possibly dangerous or lethal advice.

BB

[BinaryBillTheSailor]

Incorrect and potentially lethal advice if followed. Very few people, including George "Don't try to teach me anything" Cawthorn, take into account that there may be more than one outlet on that 15 amp circuit, and in a home setting it's almost guaranteed that there is more than one outlet on that circuit.

His judgement about power consumption is equally flawed. He's making it up as he goes, folks.

BB

[barry martin]

David:

DD> I would like to put my computer equipment on its own circuit. Would I need DD> a 15 or 20 amp breaker to do this? Are there any restrictions as far as ho

DD> many breakers can be in the box? I know there is room for more. What gaug

DD> wiring would this require?

I'd go with the 20 Amp circuit "just because" it's a little more robust in case you need more current later. Maybe it's a little cool in the Computer Room and you need to take the chill out by running an electric heater.

And for your next question, no, you do not have to use 20A rated outlets on a 20 Amp circuit - the 15 Amp duplex outlets are fine.

BTW, speaking of outlets, you might want to have a few more than one or two per wall for the equipment. Also plan ahead to position the outlets where you need them now and where you may need them int he future should you re-arrange things. Easier and cheaper to plan ahead for the future now.

- ¯ barry.martinþATþthesafebbs.zeppole.com ®

• A horse may go freely to water, but a pencil must be lead.

[zxcvbob]

You wanna explain the "potentially lethal" part?

Bob

[BinaryBillTheSailor]

You should probably hire a professional.

Here's a simple experiment you can try yourself: Get a bunch of strings of christmas lights, whose combined draw "should" equal 15 amps. Plug them in series with the last one plugged into a 15 amp outlet.

Watch the clock and let me know how long before the wires (not the lamps) heat up enough to ignite something like tissue paper or even newsprint. Surprise! In many cases that will occur without the circuit breaker ever popping. If you can, check the temperature along the length of the light strings, as well as the house wiring.

It's important to know how much of a load you are putting on a circuit, including any extentuating circumstances. I am not saying that it will be lethal any certain percentage of the time, but the percentage is certainly not zero. That's why I qualified it with the word "potentially" George Cawthon wants to "hazard a guess" as to the load, thereby creating a hazard.

BB

[zxcvbob]

That will just blow the built-in fuse in one of the strings of Christmas lights. Even if it didn't blow and the lights caught on fire, it has nothing at all to do with wiring a 15A vs. 20A branch circuit. IIRC, those strings of lights are fused at about 2A.

Basically, you're just making this stuff up as you go.

Bob

[BinaryBillTheSailor]

No, you've just added fuses, an element that does not exist in the experiment I defined. I also asked you to measure temps along the house wiring. Did you do that yet? Please actually do the work before making any more specious statements.

BB

[zxcvbob]

Those Chrismas lights you mentioned have fuses built-in to the plug, you moron.

Bob

[BinaryBillTheSailor]

Then. for the purpose of this experiment, remove the fuses and replace them with 14 gauge wire. Try again, and let us know the result. Continual whining withiout doing the work doesn't give you much credibility. DO THE WORK.

BB

[Greg]

The bullshit is certainly flying around here. Take a look at 310-16 in the NEC and you will see that 14ga wire is really rated at 20a. . Article 240.4(D) limits the O/C device to 15a so people who try these "run it till it trips" experiments or lifestyles are not really creating a hazard. If you can load a 15a breaker/14ga copper circuit enought to warm the wire you have a defective breaker.

[BinaryBillTheSailor]

Breakers are NEVER defective? That's good to know! Thanks!!!

BB

[NoOne N Particular]

I will throw in my $.02 worth here.

I currently have a "data center" in one of my bedrooms. In there I run a number of machines, and all on a 15A circuit. I have had all the following up and running at the same time:

1 dual processor Compaq server(8A) with 4 internal disk drives and two attached storage arrays (6A each). 1 quad processor Compaq server(8A) with 4 internal disk drives and one attached storage array(6A). 1 homebuilt computer system with two 800Mhz processors, three internal disk drives, two external disk drives, and a 20" monitor. I'm not sure what the power requirements are, but the monitor says 3A. Can probably figure 6A for the whole thing. 1 HP Laserjet 4M+ printer (7.6A) with duplex attachement. That would certainly be mostly for warm-up, but I would imagine it would still draw a couple of amps while printing. 1 Epson Color dot matrix printer 1 fax machine. Plus my DSL modem, router, network switch, and maybe a couple of lights. (All Amp ratings are directly off of the labels on the back of the equipment.)

This 15 amp circuit runs all of this just fine. It looks like the circuit is way over subscribed, but the ampere ratings are maximums which will

**most likely** only come into play when the equipment is initially turned on. I left all of this equipment up and running for a few days a while back and there was no problem. No circuit breaker tripping, No smell of burning plastic. :-) But this is just about the limit. I fired up another computer which is pretty much a "normal" 2.4Ghz machine with a 21" monitor, tape drive, and scanner, and the circuit breaker tripped after a couple of hours.

I'm sure that if I came in and just threw a switch and had everything all come on at the same time, the CB would just laugh at me and say "uh, NO!", but everything gets paced. I have it set up so that when I turn on a machine, the monitor comes on first, then the external storage array (if there is one), then the computer. While the computers with attached storage arrays are coming up, then the disk drives in the arrays will be spun up one at a time. Once the computer is fully booted then I can go to the next system.

The bottom line of all this is that if you just have one computer system, even if it is on steroids, 15A will most likely be fine.

[Greg]

If you have a defective breaker it doesn't matter how big your wire is. Available fault current in a home is in the thousands of amps. (only limited by the size of the service drop) That was not the discussion.

[Greg]

What happens when the power company "throws the switch"?

The real question is if you are running a NEW circuit, would you run 15 or 20. Since the cost difference is negligible why wouldn't you run the 20? The 15a breaker in your outlet/surge strip will give you that 15a protection people wanted but you can still have some excess capacity at the wall for other equipment.

[BinaryBillTheSailor]

Actually it does. If your breaker is non functional, you will be fine until you overload or otherwise abiuse the circuit, whether it is a 15 amp circuit or a 200 amp circuit. The circuit breaker is there as a backup safety device. It's presence does not mean you are free to load up circuits to max capacity and trust the breaker will always save you. The first line of safety is to properly design and use the circuit, not depend on a fallible device to overcome your own stupidity.

BB

[Greg]

The designer has no control over what a user will plug into a circuit with receptacles on it. That is the reason for 240.4(D) in the first place. I am not the one who brought up the bad breaker idea. I just pointed out when the O/C device doesn't operate you are looking at the possibility of drawing available fault current.

[Brian White]

Careful here. You can't use a 20A breaker unless _everything_ leading to the plug and the plug itself is rated at 20A. That means using 12-guage wire and a 20A rated plug (it has one prong socket that looks like a T).

If you have have more than one outlet on that breaker, they must _all_ be rated at 20A and _all_ wire connecting them must be 12-guage.

You're probably better off with two 15A breakers. You can use 14-3 wire to run two circuits through one cable as long as each of the hot wires is on a different phase. With this set-up, usually all top plugs are on one circuit and all bottom plugs are on the other making it easier for a person plugging things in to balance the load. Of course, tripping one will necessarily trip the other since it is required to have both trip together.

I got a "Simplified Electrical Code" book from Home Depot before I did my work. It's really quite easy, but there are a lot of requirements. I have 240A (at 120V) coming in to my kitchen -- I have only 200A (at

120V) service to my house! But that's code for a kitchen...

And whatever you do... Get a permit and get it inspected!!! It cost me $140 for a permit for my kitchen, including both inspections (one "rough-in" before the drywall went up and one when it was all complete). If you ever had a fire and there was even the posibility it had to do with uninspected work, your insurance company could refuse to pay.

Very true, but that's not the problem of the breaker. The breaker is designed to protect the parts of the circuit that are hidden within the structure of the house (i.e. wiring and outlets). If you plug a 1/4 watt

10 ohm resitor in to an outlet, you're perfectly within the limits of the circuit, but I guarantee that you'll see some nice fireworks from the resistor.

Anybody know what guage Christmas light wire is? Probably 16-gauge stranded, good for 10A, as I recall.

Brian ( [e-mail] )

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[Brian White]

Actually, you don't. Your breaker must be rated at the minimum component on the circuit. You could use 1ga wire if you wanted, but if you had one 15A outlet or one piece of 14ga wire, then the breaker cannot be rated more than 15A.

Don't forget that outlets have ratings on them, too! If you have a 20A breaker, you need to use 20A outlets.

Note that this only applies to the "permanent" parts of the circuit. What you plug in to those outlets is up to you.

As an aside... Running multiple circuits "ganged" together (where the wires run adjacent) reduces the rating even further since they do not have the full surface area to dissipate heat.

Brian ( [e-mail] )

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[BinaryBillTheSailor]

Which is why I specifically said: "If you can, check the temperature along the length of the light strings, as well as the house wiring."

The wiring in the wall could get quite hot without tripping the breaker. It's not common, but it does happen, and once is enough to kill somebody.

BB