Posted by Wirehead Arts :
Tim, I have never heard of a high-voltage 383. So it's very likely safe. Also, a lot of the newer dSLRs have better isolation circuits that can handle upwards of 250v.

OTOH, given that a multimeter is both a useful thing to have and also available at Radio Shack for a few bucks, it doesn't hurt to keep one around and test flashes, just in case.