Electrical Problem


  #1  
Old 11-04-03, 07:42 PM
don1
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Unhappy Electrical Problem

I wonder if you could help me out
I brought my Hi Fi across from England when I emigrated to the US.There are 6 components,amp,cd,tuner,cassette etc., running on 220-240 volt, 50-60 hertz.Up to now I have been running them on a step-up transformer I bought on the internet,it hums a lot! Since moving to another home here I have full access to a large basement and have already done some re-wiring and made some connections to the breaker panel.Now,I thought of putting in a 220 volt receptacle in the living room to run my Hi Fi,I was initially daunted and confused about the wiring arrangement of such a receptacle in that there being two hots and an earth but no neutral, but went ahead anyway, I know the neutrals and earths are on the same bar in the breaker panel.Now I am perplexed as to how to wire the 220 v plug. How do I get the 220 volts down one wire?The way I did it,it kept tripping the breaker.I wired the hot wire across the two 110 pins of the plug and the neutral and earth together to the earth,wrong huh?I believe I put the correct breaker in the panel,it's a 20 amp double pole,at least I get a reading on the multimeter of 240 volts at the two hots on the receptacle.I have a power strip that I got when ordering the transformer,it takes all six plugs for my HiFi components,I cut off the european schuko plug that went into the transformer and was then perplexed at how to wire up the cord to the new plug for the receptacle,the earth wire speaks for itself but how do I wire the hot and neutral?How do you derive the 220 volts to run something here?
 
  #2  
Old 11-04-03, 11:13 PM
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Don,

Yes, I also brought some of my Hi-Fi from the UK when I moved to the US although I only brought the speakers and the tuner (which I donít really use). I bought the rest of the stuff here having got rid of things like the amp in the UK. The DVD player luckily has a universal power supply. Unlike in the UK, in the US the 220V line is not really 220V. In the breaker panel they have two 110V lines that are out of phase. They use one phase on each leg to give you the 220V. You cannot get 220V on one line like we have in the UK. In the 220V configuration you do not have a neutral. As far as equipment like Hi-F's are concerned this should not really be a problem since most work off low voltage and should have a step-down transformer internally.

DIY books you can buy in this country will show you how to wire the 220V outlet. You wire each phase to the hot and neutral prongs and along with the earth connection should work.
 
  #3  
Old 11-05-03, 07:01 AM
don1
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Hello fellow expatriate.I'm still a little confused.Did you connect your 240 v equipment up ok,like your tuner you mention, and is it working?I have done all the wiring to the receptacle, no problem,it's just the wiring of the power strip line box cord to the 220 v plug!!I don't wire the neutral wire to the hot as well do I!!!
 
  #4  
Old 11-05-03, 07:37 AM
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What you're trying to do is simple. Not code, and not UL approved, but simple. Your existing plug will probably have 3 wires. You'll need to either get a plug converted (with 3 pins if that's what the existing plug has), or cut the plug and replace it. The ideal way would be to replace it with a 220V US plug. Even easier would be to simply get a European power strip, plug everything in it, then simply cut and replace the plug on the strip. When you rewire your outlet you'll need to replace it with a 220V outlet, but if this is dedicated you don't need to change the wiring. You'll use both the white and black wires (if NM-B) as hots (connect them to the L1 and L2 on the 220V outlet), the bare is ground. At the panel you'll need a 220V breaker (20A if 12 gauge wire, 15A if 14 gauge wire). The white and black will go to the breaker, and ground will go to ground. You'll now have about 240 Volts to the outlet. The frequency is a bit different, but it shouldn't make a big difference. You want to use a 220V outlet because you don't want to plug a 110V appliance into a "regular" outlet wired for 220V by mistake. Smoky circles may appear.
 
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Old 11-05-03, 10:07 AM
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don1,

I think I misunderstood your question. If you have wired your receptacle correctly all you need to do is to connect your Hi-Fi to the receptacle prongs so that the live and neutral of your Hi-Fi is connected to the hot legs. The fact that you donít have a neutral should not be a problem since electrical items like Hi-Fiís use a step down transformer internally and the inputs should go straight to the transformer. I would double check by opening up your Hi-Fi components and making sure that the live and natural inputs are connected directly to a transformer that is floating wrt ground. Do not connect your neutral anywhere. Theoretically it is possible to convert the US style 220V to the UK style 220V with a transformer that has a 1:1 turns ratio but if you are going to do this you may as well have the step-up.

I never did use my tuner since I came here. My plan was to actually modify the power supply internally to use 110V. I got the service manual/circuit form Sony but the conversion proved to be difficult since they had used a transformer with a odd turns ratio and I could not find an off-the-shelf replacement for it.

Trinitro is correct about the mains frequency Ė in the US it is 60Hz unlike the UK which is 50Hz. However, again most small appliances that use low voltages internally will either have a switch mode PSU or the conventional bridge rectifier/capacitor smoothing. For the second kind of PSU the US frequency will give better results as the ripple will be lower.

Hope this clarifies but make sure you open your Hi-Fi and check before hooking up.
 
  #6  
Old 11-06-03, 08:13 AM
don1
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Thankyou Rav12 & Trinitro for your replies,things are becoming clearer.I will check inside my HiFi components,I don't want to blow my stack up,it's all Sony gear,big beefy amp and surround processor and stuff!I have wired the proper receptacle and got the proper plug for it,no prob,it was just the wiring of the power strip cord that got me.All my HiFi components have US 220 v plugs on them,they work in my universal power strip,so everything was working using the step-up transformer.The Hertz thing should be ok as on the back of each HiFi component is printed 50-60 hertz.I can proceed now...tentatively
 
 

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