I have some equipment that was purchased in the UK that came with the power cord missing the plug (has 3 wires exposed; Brown Live, Blue Neutral & Green/Yellow Ground). The equipment says it is 50/60Hz so that shouldn't be a problem. My question is how do I wire a US plug to this with only 3 wires when the US needs two Live wires and a ground? Do we just hook 120v to Brown Live and 120v to Blue Neutral and Ground to Ground or does that end up putting live back to ground on the equipment? This line in the manual has us concerned:
Ensure that the mains supply is single phase alternating current (ac) of the stated frequency (Hz), with neutral nominally at earth potential
Not sure if that quoted text is just for in the UK or ??
Best Answer
You can't do it, it means exactly what it says.
The manufacturer wants "neutral" (EU blue) to be near the same voltage as ground/earth (green). They are specifically saying DON'T do what you're trying to do, connecting line (EU brown) and neutral (EU blue) to two phases of hot (US black/red).
Transformers are your friend
A step-up/step-down transformer will do what you want. It is an autotransformer that takes 120V hot and neutral, and gives 240V hot and neutral. Neutrals are at the same potential. These are packaged commercial products with the correct cords and receptacles for your market. They are heavy because they are full of copper and iron.