High-flex test lead wire is available in bulk on Ebay, and it comes in several colors. The difference is that the wire has dozens of strands of very fine wire and won't fatigue and break strands under the insulation as you use it. Regular primary wire is also far too stiff to be used for a tester.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!