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Two 700 watt blow heaters vs one 1500 watt heater?

  1. Nov 19, 2014 #1
    I bought a small 1500 Watt portable blow heater for my room cuz it getting really cold, but whenever its turned on, it trips the circuit breaker.What exactly causes the circuit to break? I mean, what units should I concern myself with when buying a heater, --Watts or Voltage? Why does this heater trip circuit when other stuff (computers, lamps etc) doesn't? Also, what uses the most power, is it the fan turning or the heating element? What if I I bought two 700 Watt heaters --would that heat the room more with less power used? Thanks for any help.
     
  2. jcsd
  3. Nov 19, 2014 #2

    berkeman

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    What is your AC Mains voltage? 120Vrms, 240Vrms, or something else? What is the breaker that is tripping rated at? 20A?
     
  4. Nov 19, 2014 #3

    berkeman

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    And what else is plugged into that same circuit that is fed by the breaker that is tripping?
     
  5. Nov 19, 2014 #4
    Asynchronous motor start current could be problem. Heating element also draw more current when they are cold. Buy rather motor starter fuse for your instalation.
     
  6. Nov 19, 2014 #5
    The room has forced air heaters mounted in the walls (two of them).. If I turn on my extra portable heater when the other heaters are on, it instantly trips the circuit. If room heaters are off, then portable heater wont rip the circuit. Also, I have a microwave in my room: Microwave + portable heater = tripped circuit. But... Microwave + room heaters = no problem. How do I find out the mains voltage and amps? is that posted on the breaker box usually?
    Thanks for the reply.
     
  7. Nov 19, 2014 #6

    berkeman

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    Look at the label on the back (or bottom) of the microwave oven. That will tell you what the AC Mains voltage is.

    The breaker box may have something that shows what the rating of the circuit breaker is. But you can't really substitute a bigger one without upgrading the electrical service (an electrician is needed for that, and you need building permits and inspections to do it).
     
  8. Nov 19, 2014 #7
    your wall heaters sound like they're on the same circuit breaker as the outlet you're plugging the heater into. Most circuit breakers in home4s are either 15 or 20 amps. Usually 15 amps if you have 14 gauge (thickness) wire, or 20A is you have 12G wier. a 15A circuit breaker at 120 volts can supply about 1800 watts of power. Since your heater is 1500 by itself, that doesn't leave very much for anything else, definitely not enough for two more heaters. In my opinion, your simplest fix is to buy a 12 gauge extension cord (MUST BE 12 GAUGE, or thicker, like 10 gauge, but you probably won't find a 10g extension cord). Plug the extension cord into an outlet in another room, a room without wall heaters. Depending what else is on that other circuit though, you still may trip a breaker. The main thing to keep in mind is converting the watt rating of heaters, to the amp rating of circuit breakers. It's P=IV, Power = current X voltage. So if you have a 120V system (e.g. you live in the US), and your circuit breaker is 15A, then the most you can plug into that circuit is about 1800 watts, TOTAL... That is, counting everything plugged in that's on that breaker, and sometimes they may even run lighting on the same breakers as outlets. If it's a 20A breaker, then you can run 2400 watts total. If you do by an extension cord to plug it in at a different part of the house, like i said, make sure it's at least 12 gauge (smaller numbers are LARGER, so don't buy a 14g extension cord)! It's still not recommended, but make sure not to use anything smaller than 12g. It may be expensive (for an extension cord), like $50 for 50' cord, $30 for a 20' cord, etc...
     
  9. Nov 19, 2014 #8

    dlgoff

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    Question. Is it a rented room; as in, student housing?

    Yep. But may not be possible depending on answer of the above.

    Waiting for reply to room question. If he is living in only one rented student room, he may be out of luck.
     
  10. Nov 19, 2014 #9

    russ_watters

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    Heaters are 100% efficient, so two 700W heaters create less heat than a 1500W heater.
     
    Last edited by a moderator: Nov 19, 2014
  11. Nov 19, 2014 #10
    hi, yes student housing and its really old building too , ...I estimate year 1900 or earlier. So I cant unfortunately use another room (i only have one room). FYI on the breaker box, it looks like each room has exactly one circuit breaker. So its easy to flip the switch again if it trips, --just a walk down the corridor --but Im looking for some ingenious way to get this place toasty warm...definitely cant build fire lol
    thanks for the answers... any more ideas?
     
  12. Nov 19, 2014 #11
    mp3car --even if I go get 12 gauge extension I dont see why it still wouldn't either trip the circuit or fail to work at all (the portable heater failing to work I mean) because its still running 1500 W. (?) that's why I was thinking of 2 700W heaters positioned opposite ends of room.
     
  13. Nov 19, 2014 #12

    berkeman

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    Sounds like adding some clothing layers would be a good (and cheaper) approach... :-)

    He was thinking that you could use the extension cord to tap into an outlet that was fed by a different breaker. Sounds like that is not an option.
     
  14. Nov 20, 2014 #13

    meBigGuy

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    Just to summarize:
    I'm assuming 120V mains. You multiply the mains voltage by the breaker current to determing the maximum watts you can draw.

    The circuit break trips when you draw too much current. Let's say 15 amps. 15 amps at 120V means you can run 1800 watts. It doesn't matter how you split it up, 1800 watts (15 amps, actually) is the limit. If it is a 20A breaker, the answer is 2400 watts.

    That is a hard limit. No exceptions. No tricks to get by it, other than an extension cord to another breaker.

    Maybe you can add 1 700 watt heater and not trip the breaker (until you run the microwave).
     
  15. Nov 20, 2014 #14

    sophiecentaur

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    If you were to have a single heater running for longer (i.e. switched on, well before you get into the room) you may get the room temperature high enough for comfort. It's not the most efficient way through but, if you are not metered, it may be worth while thinking about.
     
  16. Nov 20, 2014 #15

    psparky

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    I would return that heater and use a heater that has several different settings. They sell a radiator heater at Lowes or home depot for like $35. It also has a thermostat which is ideal for sleeping or leaving the room.

    Point is, it has three different settings, minimum (500 watt) , medium (1,000 watt) and maximum (1,500 watt) Find the setting that doesn't trip the breaker, either medium or minum in this case. By the way, these wattage differences work independently of the thermostat which is convenient for the user.

    Problem solved. 500 watts may be more than enough to keep you cozy.

    Otherwise you would need an electrician to re-wire which obviously isn't going to happen in this case.
     
  17. Nov 20, 2014 #16

    dlgoff

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    I agree.
    I have one of these Oil Filled Hearers from Lowe's in my bedroom that I'm sold on.

    611768073368lg.jpg
     
  18. Nov 21, 2014 #17

    psparky

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    There ya go. Mine has the older stye switches for the different wattage levels and then the "turn knob" for the thermostat.

    A couple of these strategically placed in a couple rooms could work wonders in a house. Even keeping the settings low for the wattage and thermostat can make a big difference. Seems like every house has that one or two "colder rooms".
     
  19. Nov 21, 2014 #18

    dlgoff

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    These oil types are much safer IMO, as the heat doesn't get concentrated to one area of the heater.
     
  20. Nov 21, 2014 #19
    I am assuming your room has a window? -- perhaps wooden pane - not good condition? If so have you considered Window Film ( http://solutions.3m.com/wps/portal/3M/en_US/NAHomeEnergy/Home/ [Broken] )
     
    Last edited by a moderator: May 7, 2017
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