I'm not sure. The advertised 240v is RMS (root-mean-square, kind of an average) voltage. Instantaneous voltage at the peak of the sine wave is about 1.4 (square root of 2) times that, or about 340v. While ratings include a safety factor, I wouldn't. Potential downside (short circuit, worse if circuit breaker doesn't kick in) is too big. Rewire. Not hard to do it yourself, not expensive to have someone else do it.