If you can purchase a Harris TS 100 you can find the open in the wire. Make sure there is no power attached. If you know that your neutral and ground are good,measure those first (exp.50') then measure hot and neutral (exp 18') your open is 18' away. Now apply tone and follow the noise for 18'. Usually works but a little more accurate than an Estwing. TS 100 is roughly 300.00 but a nice tool. Also lets you know how much wire you have on a roll of romex or any other cable pair. Plus you look really really cool in front of your customer when you tell them the problem is 18 feet away.
