How do I know if I need 20amp, or 15amp?

Discussion in 'AV Receivers' started by Adam_Reiter, Jul 1, 2003.

  1. Adam_Reiter

    Adam_Reiter Second Unit

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    We move into our new house today, (Tuesday) and I want to run at least 2 dedicated circuits back to the breaker. But, how do I know which one I should go with? 15 or 20?

    I have a huge amp (Aragon 2007) and do not want to limit its potential at all. I am almost thinking 20amp circuits since there is the also the big ol Wega 40" and the whole HT rack's worth of equipment to plug in. Another reason I need to know is I want to get one of the PS Audio Ultimate Outlet High Current model, and they come in 15 and 20 amps. I need to get the right one. I am also putting the PS Audio Power Ports in when I run the dedicated power. So I will have a top of the line outlet in there as well.

    So, look at my equipment list and tell me how I can add it up and determine what amperage I need.

    http://slaggbot.0catch.com/Home%20Theater%20Page.html
     
  2. Frank_S

    Frank_S Supporting Actor

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    Adam, if you're going to take the time to run wire, install 20 amp circuits. BTW, you might be surpriced to see how little current you are drawing, even with the big Aragon.
    I run 2 Aragon amps in my system, the 8008BB(weighs 75 lbs) & 8003(weighs 72 lbs).
    I had an electrician run a load test with my system cranked at or near reference level. It drew 9.5 amps total.
    My system at that time was:

    TW40X81 RPTV
    Toshiba SD-5109 DVD
    Aragon 8008BB 200 wt/channel amp
    Aragon 8008 x 3 200 wt/channel
    Classe SSP-25 pre/pro
    SVS 20-39 PC sub
    Rel Storm III sub
    B&W Nautilus speakers x 5
    2 Richard Gray power company devices (400s model)
     
  3. chung_sotheby

    chung_sotheby Supporting Actor

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    Frank,
    Nice setup. I bet that thing rocks when you put it at reference levels [​IMG]

    As for whether or not you need a 15 amp or 20 amp circuit, I believe that a 15 amp circuit can handle some 1800 watts or so of load (15A x 120 Volts AC = 1800 Watts), even though it is best to limit this to 80% or less of maximum output, so about 1440 watts total. This is still about 160 watts going to each speaker plus 300 watts going to the subwoofer, which is probably pushing out about 20-30 db or so above reference, depending on what kinds of speakers you have. So unless you have a very power hungry system (huge projector, massive amps, impossible to drive speakers) then a 15A circuit should be fine.

    (edited after clicking on Adam's equipment list)
    ON the other hand, you might want to get a dedicated 20 amp circuit just for your SVS amp, the QSC. I highly doubt that you will need more than 1800 amps for the rest of your equipment. Even with each speaker driven to its max power handling, you are going to be drawing 1250 watts, which leaves 550 watts for you processor, TV, CD player, DVD, etc. If you are going to get bigger, harder to drive speakers with higher power handlings in the near future, then maybe you will need a bigger amp and also 20 amp circuits for the whole shebang. But you should probably get the QSC on its own 20A circuit right now, since the B$ can pull 2500 W of power by itself.

    On a personal node, EGADS, how loud must you like your HT with that setup. Fully driven, 115 DB coming from every speaker and something like 145 DB from the B4!! In the words of Hansel Mcdonald: "How do you live!?"
     
  4. Chu Gai

    Chu Gai Lead Actor

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    The cost differential is small enough that you might as well run 20's. They can though be terminated in 15 amp outlets.
     
  5. anth_c

    anth_c Stunt Coordinator

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    Chung:

    When sizing circuits, you must consider the input wattage of each device not the output. For instance an amplifier that outputs 200 watts by 5 consumes more than 1000 watts...the heat generated by the amplifier is a by product (an overhead or inefficiency) of converting the electricity from the outlet to a signal that can drive the speakers.

    Chu:
    It is a violation of the electrical code to have a 20 amp circuit breaker with a 15 amp recepticle. Wiring and recepticles on a circuit must have a capacity greater than or equal to the over current protection device (circuit breaker). It is OK to put a 20 amp recepticle on a 15 amp circuit...if more than 15 amps is drawn, the circuit breaker will trip.

    In the other case, placing a 15 amp recepticle on a 20 amp circuit could overheat the 15 amp recepticle as the circuit will supply 20 amps before tripping.

    Note that a 20 amp recepticle accepts the cords designed for 15 amp circuits (they are backward compatible).
     
  6. RichardHOS

    RichardHOS Second Unit

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    couldn't you just as easily use a 15-amp circuit breaker?

    Go ahead and run wiring rated for 20-amp though in case you ever need the extra juice... the wire itself doesn't cost much more, and there's no codes agains using heavier wire than required, so long as the breaker is the weak link (i.e., rated the same as or less than the receptacles).
     
  7. Kevin C Brown

    Kevin C Brown Producer

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    Bought a house. Has an addition. I was pleased to find out that when the addition was done, they did 2 good things:

    1) properly grounded
    2) 20A circuit

    Had 15A outlets. Against the electrical code? I doubt it. Passed an official ASHI home inspection. But I think you have it reversed. I certainly don't think it's a good idea to put 20A receptacles on a 15A line, then rely on the circuit breaker to trip if you overload the line. Not safe. BTW, the only difference between the 15A outlets and the 20A outlets that I looked at, was the connection itself. The physical construction of the outlets was identical.

    Me? I upgraded to a 20A hospital grade outlet.

    Adam- If you're adding from scratch, get the 20A line. I'm currently using an Acurus A200 plus an A200x5, and couldn't be happier. [​IMG]
     
  8. Chu Gai

    Chu Gai Lead Actor

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    Did you run that as an isolated ground Kevin?
     
  9. Kevin C Brown

    Kevin C Brown Producer

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    Chu- Previous owner, but yes, has an isolated ground. And yes, the CATV line ground is not tied to it, and yes, if I don't take precaustions, I do get a ground loop hum. (I have an isolator in my Equitech that I run the CATV line through that gets rid of it.) Presuming what you were asking about... [​IMG]
     
  10. chung_sotheby

    chung_sotheby Supporting Actor

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    Anth_
    I understand that not all wattage from an outlet is converted directly into output wattage. That is why I stated that the other components are going to be using some wattage as well, even though they are not driving any speakers. To find the true amount of wattage an amp is drawing from the line at max output, one should find the figure for the max power drawn by a component. Sometimes amps state that they are 100x5, but their power supplies can only handle somthing like 450 watts total, like some of the lower-end Sonys and other receivers. But for a general idea of how much power is drawn by an amp at max speaker power handling, adding up the max power handlings of each speaker is a good way to find a rough figure. That is, unless someone is using Tube amps, which are less efficient than solid state in the conversion of line power to amp power.
     
  11. Wayne A. Pflughaupt

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    Location:
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    Wayne
     
  12. Simon Ngan

    Simon Ngan Stunt Coordinator

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    Actually I was surprised when I used the "Kill-A-Watt" to measure my HT power usage. While most of the gears measure up against the specs, I was amazed with the amp and sub amp usage.

    I have Aragon 2005 which at idle, it's drawing about 120W. While at somewhat heavy load (no reference level though), it goes up to about 150W. Then the ML Descent sub, at idle again it draws roughly 100W and even when I play some test tones from AVIA, it goes up to around 110W.

    Of course, this doesn't mean I don't care about power usage but I worry less about the electrical bill [​IMG]

    If I don't have a dedicated circuit for the HT, would it still be better using a hospital grade receptacle where I plug the Panamax 5300? I have everything plugged into the 5300. I'm more concern of the safety rather than sonic difference.

    Thanks,

    Simon
     
  13. Chu Gai

    Chu Gai Lead Actor

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    Hospital, industrial grade and a host of others are a bit more robustly constructed and if you're doing the work yourself, the cost differential is pretty managageable. BrianOK has posted on a variety of aftermarket receptacles and sources. Run a search on some of his posts.

    As an aside, a preference of mine when attaching wires to the receptacles is to use the screws instead of stabbing the wire in. I just happen to like solid mechanical connections.

    Nothing like good grounding Kevin. Solves a host of problems [​IMG]
     
  14. Kevin C Brown

    Kevin C Brown Producer

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    Chu- On my list of things to do (someday): track down the ground for the addition, track down the ground for the CATV line, and connect them. Someday! [​IMG] Yeah, the hospital grade outlet I have, only cost $10, vs maybe $1.50 for a "run of the mill" 20A outlet.
     
  15. Chu Gai

    Chu Gai Lead Actor

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    Out of curiousity Kevin, how would you characterize the soil where I assume you've got a grounding rod driven in? Sandy, clay, dry, etc?
     
  16. Kevin C Brown

    Kevin C Brown Producer

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    Chu- As far as I know, the general description for where I live is clay. ??

    (They call it "expansive soil" under my house.)

    Very dry in the summer (3 months no rain), but then moderately wet in the winter.
     
  17. Arthur Vino

    Arthur Vino Stunt Coordinator

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    guys, questions for experts:
    I am buying ATi 3007 amplifier (300 wattsx7), so I know I Must use 20 amp circuit. Also, this AMP comes ONLY with 20A plug (for safety), so it is impossible to plug it into 15a circuit.
    My questions are as follows:
    1) How do I check what kind of line do I have now?
    2) How do I rewire it into 20A circuit?
    3) I heard the outlet looking a bit different, any pictures? and will Home Depot have them outlets?
    4) How do I test it and make sure I am getting enough juice to generate 2100 watts of power ATi 3007 is capable of?
    Thanks
     
  18. Chu Gai

    Chu Gai Lead Actor

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    If the wire running to your receptacle is 12 gauge (read what it says on the romex) then all that's needed is to replace the 15 amp breaker with a 20 amp one followed by replacing the receptacles with 20's.

    HD has all the stuff.

    You won't have any trouble whatsoever running that on a 20 amp line. My son's got a 5000 watt Crown running off of 15 and he's never tripped the thing.
     
  19. Arthur Vino

    Arthur Vino Stunt Coordinator

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    Thanks Chu, what would be the cost of breaker and receptacle?
    I assume if my wire is not 12 gauge, then I need to rewire everything.
    thanks
     
  20. Chu Gai

    Chu Gai Lead Actor

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    Hey, like I know all the prices?? [​IMG] The prices bounce around depending on the particular vendor. Just pop on over to HD one evening and ask one of their knowledgeable individuals. They'll point out what they've got. Now even though the 4th is tomorrow, I don't want to hear that you lit yourself up!
     

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