Heavy Duty wire flush cutters works well for 12 or 10 gauge copper - sterling extra long handles for leverage

These give you the extra strength for cutting heavy gauge wire. I've included an image with my black handle cutter next to these to show the size difference. My black cutters  are super but these are better still. The longer handles give you more leverage for cutting through the wire.
This makes it easier on the hands. These are for jewelry metals such as Sterling, copper, brass, aluminum. Not for steel.