is accomplish In Europe, many outlets (German ones spring to mind) are mechanically symmetrical with respect to swapping hot ("Live") and Neutral pins, and AFAIK all equipment has to be able to operate whichever side of the input is earthy (=close to ground potential). I would have no qualms at all about running European equipment of 120 - 0 - 120, although for travel I have made my own autotransformer from a 100VA split-primary mains transformer. Some old (before about 1960) equipment bonds neutral to equipment chassis. This is of course dangerous to run except with the correct side earthy. I have heard rumours of German equipment with a neon between chassis and earth that lights up if you get this wrong! When wiring a step-up transformer: Single winding (autotransformer) should have neutral one end, 120V in the middle and you get 240V out of the other end. Ground (earth) goes straight through without connecting to the windings. Dual winding (isolating transformer) Input across Neutral and 120V - output gives you 240V. Bond one side of the output to Ground, NOT neutral, and this becomes the new neutral [*]. This ensures that a fault to the chassis is guaranteed to trip earth leakage protection downstream of the isolation transformer (which I doubt you have) but not upstream of it. This is much safer if (for example) hot and neutral are reversed on the input. (Note: if you wire one side of the output to neutral, you have something no worse than the autotransformer.) I don't know whether this latter meets the US electrical code, but it is correct :-) As regards strange sockets, I don't imagine 3-phase would be at all likely in a US domestic installation, but 220V happens occasionally. The usual plug is just like the standard US 3-pin plug, but with the two flat pins at 90 degrees to their familiar position. This can roughly be represented in ascii-art thus: o o 120V _ _ 220V | | DEC used it on a lot of their European equipment... Philip [*] For full isolation, don't link ground on the two sides of the transformer. Link chassis etc. on the output to the virtual ground terminal that's bonded to the supply rail you've chosen as neutral. This means that you have to touch both a hot wire _and_ the chassis befor it will zap you. For some testing, don't bond at all - you can't detect a fault to chassis, but you need a fault _and_ to touch the wrong wire before you get a shock... Some more ascii-art, for the record. Autotransformer: ________ 240 C C 120 ____C C C N ______C_______ N Isolating Transformer wired as Autotransformer: _____ 240 ||C ||C 120 _____||C C||C C||C N ______C||C____ N |____| Isolating transformer: _____ 240 ||C ||C 120 _____||C C||C C||C N ______C||C____ N - Bond this to earth and/or chassis as necessary ********************************************************************** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept for the presence of computer viruses. Power Technology Centre, Ratcliffe-on-Soar, Nottingham, NG11 0EE, UK Tel: +44 (0)115 936 2000 http://www.powertech.co.uk **********************************************************************