Light does not work no power, but if you touch the tester to the ground wire and black line it works. What could be the problem? This in the ceiling light not the switch. Thank You.

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?:confused: