Amps: How much does a computer take?

Now heres a nice little question I got.

At my place that I'm renting currently. I got a 15Amp circuit for the whole second floor and some misc lights. 2 Hallway lights upstairs, 3 lights in each bathroom upstairs and down (1 light connected to 1 switch and the other 2 lights connected to another switch for each bathroom), also the stairwell light to the basement.

Now this comes into play here. I have my rig upstairs. I got a 2405FPW and also a 17" NEC LCD hooked up to my main rig. I also have a printer and scanner but thats not on all the time so its not of concern. Anyways the issue im running into is my rig and the AC. Its all hooked on one stupid 15amp line. Its a place im renting so its not the easiest thing to replace since well its not mine. It can idle and I know I can do other things have a light on here or the 20" TV in the bedroom on and the little TV I got in the office but its limiting my use of the PC. GRRRRR

Now do you think its possible that I can just slap a 20Amp circuit breaker in teh box and all will be good? Or don't you think thats possible at all? The breaker was installed back in 1979, and the place is a little old but I know they've done work to it over the course of the years. I asked my management company if its possible to upgrade it but no response back from them yet.


Does anyone know what a typical high end system will consume amperage wise from a 120V line at idle, full load etc? I was thinking maybe I can setup something in the bios that if I want to use the PC when the AC is on I could switch it to downclock the CPU, lower the voltage, and have low voltage on the video card during these times so at least I can use the PC and if I accidently go peg the CPU or start using the video card for a little game in a window or something its not going to blow the breaker all the time.

Hopfully this made some sence

Should say on your power supply. The box beside me (IBM x206m) is 9 Amps max, my laptop (IBM G40) uses 7.5 Amps max (but it's a desktop replacement).

If they haven't upgraded the wiring of the place, I wouldn't touch the breaker. Otherwise, I'm no electrician, but I can't say I haven't solved problems by installing a larger fuse before.

I'd contact your management company/landlord and see if they would be willing to update the wiring so that you can run two things at once, either remap a few of the outlets onto a new circuit or add new outlets on a new circuit.

su root said:

Should say on your power supply. The box beside me (IBM x206m) is 9 Amps max, my laptop (IBM G40) uses 7.5 Amps max (but it's a desktop replacement).

If they haven't upgraded the wiring of the place, I wouldn't touch the breaker. Otherwise, I'm no electrician, but I can't say I haven't solved problems by installing a larger fuse before.

I'd contact your management company/landlord and see if they would be willing to update the wiring so that you can run two things at once, either remap a few of the outlets onto a new circuit or add new outlets on a new circuit.

Click to expand...

Well says input current 14Amps @ 115V which I know is not anywhere close to what it uses (considerably less). Probably when it blows a fuse or something within the PSU thats what its rated for.

I mean I had 2 Decent Systems, 1 OK system and a Decent Highend Laptop running with more then a few lights and a TV all playing at the same time on the circuit and lights wouldn't flicker at all when booting up or kicking it on for gaming. Just that evil AC unit hehe.

Ya i'm incontact with the management company talking about it currently but havn't gotten far with it yet with the breaker situation, but I guessing new wiring would need to be brought upstairs for that and its not the easiest thing in the world to run wire though walls that you don't want to tear apart.

I'm not sure what my PSU pulls at max ...but I installed my AC a few weeks ago...and in my case I have the whole living room running off of a 15AMP breaker. (TV, stereo[which is on all the time as the sound goes through it], SAT, Rig in Sig, sometimes a second PC, 2 60w lights.....ummmm DSL modem....a few others minor things....yadda yadda.

But anywho...it's tripped....but only once. I usually just cross my fingers and make sure whatever I'm using on the PC is backed up or saved...and then switch it on. And so far it's only done it once.

I've considered upping to a 20AMP just to be safe...but just havn't done it yet.

I can't imagine that the landlord would care if you changed from a 15amp to a 20 amp...especially if the 15amp is tripping. And especially if you are going to pay for it.

If you can just move it to a different circuit, of course amperes are watts/volts so a 600 watt sustained ps would draw 5 amps from a 120 volt circuit
(P=VI), but peak draws could be greater and especially appliances can be conservatively rated in regards to peak draw (on startup & what not). Increasing the capacity of the breaker will solve the problem but you don't know the quality of the wiring inside the house/apt. It is best to just change it to a different room/circuit

But like I was saying the whole second floor is one circuit, except 1 spot, the 4 bathroom outlets (2 up 2 down) are hooked up to a seperate 15Amp circuit. But im using a 9Amp AC downstairs on one of the outlets so there goes that idea. There is no way I can just up and move it to another circuit, and theres no way I'd run a cable through the wall some how just to plug it in downstairs for the computer.

I mean I can have the computer idling and doing minor things (websurfing, some CPU intensive tasks) but as soon as the video card fires up, which means the CPU is fired up at least 1 core, its over.

Then comes the question if I drop my clocks to say stock, drop my voltage well beyond stock (can drop it to 1.1V if not lower but never tried) drop video clocks/voltages down (think 300/400 is stable with 1.000/1.8/1.8V if not it should be). That should eliminate me at least when the rigs fired up from blowing the breaker i'd think.

Get a more efficient PSU, IIRC Seasonic makes some. Often sold as "green" PSUs. Throw out that OCZ one and get a lower rated one, only as much as you need no more, that also helps with Power consumption: a PSU runs most efficient at approx 75-85% usage. Get a good UPS to buffer load spikes especially when turning devices on.

You cannot just replace the breakers with 20Amp ones unless you want to pay a hefty fine to your local county building office. Or if you're really lucky the house will burn down (no joke, distinct possibility) and you have ruined your life.

Almost forgot: don't buy a PSU with detachable leads like your current Ocz one. That costs power and is a cause for crashing rigs too.

you should be able to run a new line just for your computer

my dad did it the other day for mine

klingens said:

Get a more efficient PSU, IIRC Seasonic makes some. Often sold as "green" PSUs. Throw out that OCZ one and get a lower rated one, only as much as you need no more, that also helps with Power consumption: a PSU runs most efficient at approx 75-85% usage. Get a good UPS to buffer load spikes especially when turning devices on.

You cannot just replace the breakers with 20Amp ones unless you want to pay a hefty fine to your local county building office. Or if you're really lucky the house will burn down (no joke, distinct possibility) and you have ruined your life.

Click to expand...

Right now I know im pretty close to the limit, think I draw right around 440W at full power so its roughly 85% of capacity on on my unit. But ya I'll be getting a better UPS for this system. I got a low wattage one that I had for an older system but I'll be using that on some other things then getting a nice one for this rig. But doubt it will eliminate the issue.

I know I can't just replace the breaker unless the wires are 12ga (which i doubt they are) but if they where and was able to put a 20amp breaker in, my question still would be do you think it would still blow the breaker with my system at full load and other items on at the same time?

klingens said:

Almost forgot: don't buy a PSU with detachable leads like your current Ocz one. That costs power and is a cause for crashing rigs too.

Click to expand...

My OCZ doesn't have have detachable leads. There all built in.

techun said:

you should be able to run a new line just for your computer

my dad did it the other day for mine

Click to expand...

Might have to consider that and just rewire that whole room to a 15amp breaker. Which is more then plenty for just that room.

I'm prettry shure if you replace the breaker in the apartment to say 20 than your just creating a power problem somewhere else. If the units were designed for 14 amps and you suck 20 your sucking up 6 amps for the floor that arn't there so you might screw everyone over and cause your wiring to burn up.

Ya not going to do that. But just removed something from my line that was using 2Amps and the light flickering is gone at least when the computers idling and a few lights on.

I'll just have to live with it while I live here oh well. BTW its not an apartment its a townhouse and we have our own seperate feeds into the place so I wouldn't be screwing anyone out of any power if I changed the breaker. I'd just be frying my own wires due to them being rated for only 15amps (I checked). Besides I couldn't add a breaker to my box (at least using another slot in it) because its full. Ehh I'll save a few bucks not running the PC when the AC is on oh well just that much more insentive to save up for a house

Depending on the age of the wiring and appliances that are plugged/wired to that breaker, putting a 20 amp fuse in could possibly cause BIG problems.

If the breaker is tripping it is usually a good thing. You do not want to overload the circuit and not have it trip becuase your new breaker isnt seeing a problem. Electrical fires suck.


Talk to you Landlord/Building Engineer and see if they have any options. Other then that, move the PC to a different room.

You might also try just replacing the 15amp breaker with a new 15amp breaker. Contacts in breakers corrode over time and can cause power fluctuation and unecessary tripping. At the worst, it would be a $10 experiment that may or may not improve things.