240 volts through 110v power-strip

Discussion in 'General Electronics Chat' started by nericheath, Aug 8, 2012.

  1. nericheath

    Thread Starter New Member

    Aug 8, 2012
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    Would it be "safe" to run a US style 110v 60Hz, Power-strip at 240v. 50Hz Aus/NZ power. Moved to NZ a while ago and have weaned myself off of the step-down transformers but have a bunch of dual voltage wall warts with US plugs. Can I plug them into a US strip and then use an US->Aus adaptor to plug the power-strip into the wall. No one else has access to these cords/plugs. I know it'd work mechanically, I'm just worried about any possible heat or insulation issues over time. Any other issues I should be considering? (the powerstrip is switched but not surge protected.)
    Thanks in advance
    Eric
     
  2. BSomer

    Member

    Dec 28, 2011
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    I would say that it is probably not a good idea. Mainly because the power switch used to control the strip most likely isn't rated for 240VAC. Another item is if there is a fuse or circuit breaker, that may not protect anything. Your best bet is to try and find a new power strip.
     
  3. #12

    Expert

    Nov 30, 2010
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    It just isn't good practice to run anything at twice the voltage it is rated for. With all the computer aided engineering programs intended to make things as cheap as possible, you can't possibly guess how many clearances aren't quite good enough to be safe or reliable.
     
  4. nericheath

    Thread Starter New Member

    Aug 8, 2012
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    Thank you very much for your quick replies. I already have an NZ power-strip with 6 wall warts, each with a US->NZ Adaptor. The adaptors make the already awkward wall warts even more ungainly. I'd been hoping to replace the US plug on my power-strip with an NZ one and not have to use adaptors at all. If I remove the switch so it's just a straight Hot/Neutral/Ground wiring would that be ok? Or are the wires possibly an issue. The wiring I've seen in New Zealand doesn't seem any more robust than in the states. If the overall wattage is the same does it matter if the voltage is 110 or 240? (I know I'm being a poster child for the concept of a little bit of knowledge being a dangerous thing.)
    Thanks again
    Eric
     
  5. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    It's unsafe (and possibly illegal!) to run 240v to 110v receptacles.

    A far better idea (if your appliances will run from 110v or 240v) is to replace their plug-in 110v IEC leads with local 240v IEC leads (like on computers and laptop PSU boxes), or if they are not removable leads you can cut the plug off and use a local 240v plug PROVIDED as I said the appliances will run safely from 240v.
     
  6. nericheath

    Thread Starter New Member

    Aug 8, 2012
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    Thanks for the reply. I've already replaced all leads possible, these are the ones with black boxes with 2 pins sticking out. Just a few hard drives and a router. Replacing the dc transformers here is crazy expensive. Yes, these are currently running on 240 now. All that will be plugged in are 5-6 DC transformers that draw 100-240v 50/60Hz 1.2A. (12v 3.0amp out)

    I'm trying to learn. Is it the wire itself that is the problem or is it the design of the receptacles. Is the 240 more likely to jump the gap and spark when you are plugging something in. The same power strip ran this load just fine on 110, why is it unsafe at 240? Wouldn't the Wattage be the same? I know there is more to it than this that's why I'm here.
     
  7. Paul Kerry

    Member

    Jan 9, 2012
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    That's just what #12 was saying that the 240 more likely to jump the gap and spark or cause a melt down and a possible fire risk.
     
  8. nericheath

    Thread Starter New Member

    Aug 8, 2012
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    Thank you all very much for your time and attention. Any chance you could point me to an online publication that would explain what the functional differences are between a 110v 20amp circuit and a 240v 10amp circuit (single phase)?
     
  9. #12

    Expert

    Nov 30, 2010
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    The word, "functional" is tripping me up. Both of those scenarios deliver 2400 watts (give or take safety margins required by the local or national electrical code). One has wider spacing and the other has fatter conductors.

    Wanna clarify for me?
     
  10. vk6zgo

    Active Member

    Jul 21, 2012
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    My guess is the NZ Electrical standards are what is important.
    These may be on the Web,but I doubt it.

    From what I have seen of US 240V plugs,they certainly make a distinction between 120 V & 240V .
    The 240V are better insulated & generally more rugged in that country,so if the voltage difference is deemed important back in the USA,that should be a good indication that it will also be the case in NZ.

    At the end of the day,even if the insulation,etc is adequate,it is unlikely to be legal & if you were extremely unfortunate & had an electrical fire,it gives the insurance company an excuse to weasel out of paying up.

    Of course,the main reason for different styles of plug is so that less knowledgeable people don't try plugging in non-dual voltage 120V devices!
     
  11. nericheath

    Thread Starter New Member

    Aug 8, 2012
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    Excellant point about the insurance issue. They are adept at weaseling through the tiniest openings. I have been unable to find the AS/NZS 3000:2007, to get an actual requirement for wire gauge and insulation. Since I've been here I've changed more than a dozen lights outlets and cord plugs. Not a single wire has been larger than the 110v wires in the states. - Nothing is even close to the US240v.
    The only difference i have noticed so far is the outlets (called power points here) nearly always have a switch for each plug. Oh yeah and their light switches are upside down.
    I guess my real question is: If I run 1200 watts through a wire does it matter if its 120v@10amps or 240v@5amps? Would the higher voltage at the same wattage cause the wire to heat up more or less or the same. Would the higher voltage allow it to spark across a wider gap?
     
  12. vk6zgo

    Active Member

    Jul 21, 2012
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    You are getting hung up on the size of the conductors.
    Obviously, for the same wattage device,you can use thinner conductors with 240V supply than with 120V.
    Remember that the US 240V supply is really just two 120V supplies "back to back",so the current requirement carries over.

    With the Aust/NZ system,10A at 240V is the standard.
    If higher current is required,15A & 20A wiring is available,with the appropriate General Purpose Outlet (GPO).

    Your last question hits the nail on the head!
    The difference between the specifications of the two voltage levels is that the insulation requirements are more stringent for the higher voltage.
    This involves not only wire insulation,but distance between conductors in the actual power board,or whatever other device is involved.

    In the real world,the 120V power strip may well have adequate insulation for the job,but it is in the nature of things to have standards,so that there is a margin for error.

    Quite apart from the ratings of the power board,there are other considerations.
    For instance,although you may be able to do it safely,the licencing authority knows there are a lot of people who will do just what you propose to do,then either because they don't have your knowledge,or just in an absent minded moment,plug in a non- multiple voltage 120V device which will overheat,& cause a dangerous situation,perhaps even a fire.
     
    Last edited: Aug 13, 2012
  13. vk6zgo

    Active Member

    Jul 21, 2012
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    YES! of course it will,but the normal way is to insulate for a higher voltage than you are using to allow a margin for error,so this may be why the 120V & 240V stuff doesn't look much different.

    If you draw 10 amps through a wire of a given diameter,it will have less voltage drop than if you draw 20 amps through it.

    This is the reason for higher voltages in the first place,less current needed to do any task,hence less voltage drop,or a smaller conductor can be used for the same voltage drop.

    You seem to be hogbound on doing this,but please read my previous posting again,especially the last part!
     
  14. nericheath

    Thread Starter New Member

    Aug 8, 2012
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    I'll see if I can find better 110 -> 240 plug adaptors. The ones I have are a little too universal and don't make a secure connection (which sucks for hard drives).
    Thank you all very much for your help.
     
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