On Apr 1 2005, 19:33, Philip Pemberton wrote: 2.5mm It may depend on what you're asking for. What do you mean by "#4 copper wire"? 4SWG, which is just under 1/4" diameter? 4AWG, which is somewhat slimmer? That might be "wire" to the company that runs the mill that makes it[1], but it would be "copper rod" to most of the rest of us. Try a model engineering supplier. Or do you mean insulated cable? That would have a cross-sectional area of between 21mm^2 and 28mm^2, depending on whose wire gauge you used, and would have a current capacity of something like 150 amps, continuous, in an enclosed space (like a conduit). Almost double that in free air, more for intermittent use. Try a welding supplier, and ask for the cable used for earth clamps, or buy a cheap pair of jump leads. Or do what I did, and twist 3 or 4 thinner cables together. I have a cable that will run about 350A-400A, good for a fairly decent spot welder. [1] I once got some 3/8" square silver steel from the local wire works. They called *that* wire, too. -- Pete Peter Turnbull Network Manager University of York