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Household Amperage

Discussion in 'General Hardware' started by AsRock, Dec 13, 2009.

  1. AsRock

    AsRock TPU addict

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    well i originally thought our living room was on a 50\50 amp fuse which is not the case it's on a 20 amp at the main electric box.. As you can see in my specs i could easy hit over a 20 amp draw right ?.

    BUT if the room in question was only allowed 20 amps should the fuse gone by now or does it limit the ampage available to the room ?.

    To my understanding if the ampage is too high it should trip it right but thats never happened which has me kinda puzzled due to the fact just the 2 comps and draw 350w idle and thats not in cluding a mp and another monitor and a 40" HDTV.

    Could this be right ?
    http://www.powerstream.com/Amps-Watts.htm#watts-amps

    IF thats so why would a PSU have a max 60 amps.

    EDIT:So actual usage be around 25 amps ?.

    I know i'm missing ome thing here i'm on a need to know HA.
     
    Last edited: Dec 13, 2009
  2. Arctucas

    Arctucas

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    What voltage?

    Basically, Watts ≈ Volt-Amps (VA).

    The PSU has 60A @12V = 720W.

    If the PSU is 80% efficient, 720 ÷ .8 = 900VA from the receptacle. If 120V, the amperage drawn would be ~ 7.5A. If 240V, the amperage would be ~ 3.75A.
     
  3. hat

    hat Maximum Overclocker

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    Your house uses AC and your computer uses DC. A power supply is essentially a big AC/DC adaptor.

    In AC, one amp is 1000 watts. In DC, an amp can be anything. Your power supply will never draw 60 amps AC, however, it could have a 60 amp +12v rail, which would produce 720 watts max. That's not even one entire amp in AC, but it is 60 amps in DC because of the voltage (12).
     
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  4. AsRock

    AsRock TPU addict

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    110v max load is around 325w for just one comp.. Think it's around 25 amps but not 100% sure lol.


    Silly me lol...
     
  5. Arctucas

    Arctucas

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    How do you come up with 325W?
     
  6. AsRock

    AsRock TPU addict

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    Fan controller tells me the watts usage.
     
  7. Arctucas

    Arctucas

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    OK, so that is 325W DC.

    DC wattage is calculated using Ohm's Law; P=IE. (P)ower equals I (current in Amperes) times E (Voltage).

    AC actually uses VA (Volts-Amps) because Reactance, rather than Resistance, is present in the circuit. But, generally VA ≈ W.

    You want to know the Amperage drawn from the receptacle, so you need to know the efficiency of your PSU at the load you are applying. Then, follow the example from my first post.
     
    Last edited: Dec 13, 2009
  8. Kreij

    Kreij Senior Monkey Moderator Staff Member

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    A 20 amp curcuit (@120V) will give you 2400w of power before the breaker kicks.
    A 15 amp curcuit will give you 1800w.

    You cannot look at amperage alone. 60 amp draw at 12 volts is 720w. Easily handled by the curcuit.
     
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  9. SummerDays New Member

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    New Egg has a nice device called a "Kill A Watt" meter for $20.

    Plug it in, and it will show you directly how much amperage you're using, Wattage, Voltage and the frequency of your electricy.
     
  10. AsRock

    AsRock TPU addict

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    Thanks, that pretty much clears every thing up :p :).
     
  11. Frick

    Frick Fishfaced Nincompoop

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    Why did you think that? 50A in a regular house is insane and totally not needed.
     
  12. AsRock

    AsRock TPU addict

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    Well thats what ya get listening to the landlord lol.
     
  13. Frick

    Frick Fishfaced Nincompoop

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    ^^
     
  14. sneekypeet

    sneekypeet Unpaid Babysitter Staff Member

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    The sticker on your power supply should show the input voltage and amperage that it draws from the wall.
     
  15. AsRock

    AsRock TPU addict

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    it does and it's 60A but i would of thought that be only at full load which it's never going get to with a single card... The actual electric box is 50A\50A ( joined ) and the rest are 20A but as it being AC amps it's taking a lot less than if it was DC amps ( a lot less ).
     
  16. sneekypeet

    sneekypeet Unpaid Babysitter Staff Member

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    wow my 1000W silverstone says like AC input 100-240V, 15-7.5A, 47-63Hz

    Im not saying you are wrong but you may be reading the numbers wrong. If it could pull 60A it would blow something fast.
     
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  17. AthlonX2

    AthlonX2 HyperVtX™

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    if you pulled 60A from the wall it would trip a breaker or possibly melt the wires in the wall...there is no possible way to get around,because state codes define all wall outlets are to be 20a MAx,if they are any higher they must be painted with a special color on the recept.
     
  18. Mussels

    Mussels Moderprator Staff Member

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    he's reading the amperage from the 12V rail sticker on the PSU (output) not from the input
     
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  19. Ghoest9 New Member

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    Your normal outlsts are either wired in 14 gauge wire(rated for 15 amps) or 12 gauge wire(rated for 20 amps.) You might have some 10 gauge wiring(rated for 30 amps) but it wont be going to normal outlets; it might be for the hotwater heater or an oven. Its doubtful that you have any wiring large enough for a 60 amp breaker; it would only be used for something like a huge HVAC unit or if for some reason you decided to light a field of dreams with metal halides.
     
  20. DR.Death

    DR.Death New Member

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    every thing in a house hold it normally nothing over 40 amps the stove dryer and hot watter heater are only 30 amps so is the electric heat most hvac equipment in residential it still normally under 30 your comp probably only draws 2 amps ac at most then the psu converts that to dc
     
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  21. AsRock

    AsRock TPU addict

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    Reading it totally wrong lol.

    Yep silly me again. Just did not realize that AC amps were different than DC amps lol. I've seen both parts of of the stickers and never gave it a thought umm.

    And the washer :). From what i been reading it's more like 3-4 amps DC the comp draws at most.

    Well i guess ya learn some thing everyday ha.. Should of noticed before though.

    So can you convert 1 AC amp to DC amps ?. With a 110v line
     
  22. keakar

    keakar

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    straight from coolmax specs:

    imput power: 12A @ 115V, 6A @ 230V

    so all it draws is 12 amps from your outlet

    i would say however that this is high enough that it would be using most of the amperage available for that fuse so its a good idea to not have anything else plugged in on the same set of outlets used by that fuse. (except a lamp or radio)
     
  23. keakar

    keakar

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    wrong, wrong, wrong, i spent 30 years working on, building, and repairing a/c heating and electrical things in houses:

    dryer= 30 amp breaker

    water heater= 30 amp breaker, 40 amp if its a 50 gallon

    stove= 50 amp breaker

    outdoor a/c unit= 30 amp for up to 3 tons, 40 amp for 3 1/2 to 4 tons, or 50 amp for 5 tons

    central electric heater= 60 amp breaker for 10kw heater, 60 amp + 30 amp for 15kw (2 supply voltage wires and 2 breakers), 60 amp + 60 amp for 20kw (2 supply voltage wires and 2 breakers) basicly its 30 amp breaker for each 5kw of heat you have


    the quote above is wrong also

    this is how it it supposed to be:

    all power supplied throughout your entire house to each room uses a 12 gauge wire (rated for 20 amps)

    all outlets in every room throughout your entire house are supposed to be wired on a 12 gauge wire (rated for 20 amps)

    all lights in every room are usually tapping power from the same feed as that rooms outlets but it uses a 14 gauge wire (rated for 15 amps) (only lights use 14 guage wire)

    your refrigerator, microwave, vent hood, garbage disposal, spa tub or whirlpool bath motor should all have their own individual designated 12 gauge wire (rated for 20 amps) going straight to the fuse box with nothing else connected to it.

    a small water heater may have a 10 gauge wire (rated for 30 amps) running to it but unless its a short wire thats not far from the fuse box you are better off with an 8 guage wire (rated for 40 amps) to prevent voltage drop but code doesnt require it.

    in most cases you see a window a/c unit running a 10 gauge wire (rated for 30 amps) but its not very common to see 10 guage being used much.


    ac wiring suffers from voltage drop issues so the longer the wire the bigger it must be to keep the voltage and amperage suplly up.

    a 20-25 amp device 10 feet from fuse box (like a small outdoor a/c unit) only needs a 10 guage wire but the same device put 50 feet away on the other side of the house needs a 8 guage wire minimum because at that length the 10 guage wouldnt be supplying the voltage or amps and the wire gets hot and melts to start a fire.

    i forget the formula but i think it was something like go up one guage size for every 35 or 40 feet of length you have to go
     
    Last edited: Dec 15, 2009
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  24. Zubasa

    Zubasa

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    Good read.
    Thankfully Hong Kong follows the UK standards.
    So we run 220V AC @50Hz and each wall outlet is limited to 13A. (BS1363 Fused 13A)
    Therefore we have less problems from high currents.

    Things like A/C and Heaters are another story :p
     
  25. Kreij

    Kreij Senior Monkey Moderator Staff Member

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    AC amps are not different from DC amps. The same rules apply to each. The PSU still has to have the power from the outlet to convert to DC.
    Watts = Volts x Amps

    The difference is that the AC Voltage is 120, while the DC is 12 or 5 or whatever, when it is converted. You still need to get the power from the same source.

    120 volts (AC or DC) at 1 amp = 120 watts.
    12 volts at 10 amp = 120 watts.
    120,000 volts at 1 mAmp = 120 watts.
    0.12 volts at 1000 Amps = 120 watts.

    The breakers in the house will limit the current you can draw on a single circuit to prevent a meltdown of the wiring. But if your house has a 200 Amp feed at 120 volts, you can potentially draw 24,000 watts into one line. That is why there are breakers. Pulling 200 amps at 120 volts through a 12 guage wire will make for interesting pyrotechnique effects.
    All bad for a homeowner.
     

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