How ignition leads can get broken?

recently (2 months ago) i replaced spark plug cables with a new supposedly oem part days ago i have noticed that 3 out of six are already faulty causing missfire , i prepare myself to change them again but i want to know what can be the cause.. spark plugs and distributor components are in good order leads are not damaged just loose resistance and cause visible in dark spark jump along the insulation..How ignition leads can get broken?
they could have been defective in construction (assembled by child labor) or road salt or not snapped on tight any case the part store should warranty them buy a better set i really don't trust auto zone / pep boys , auto parts on these partsHow ignition leads can get broken?
could have been old when you got them you dont know how long them been on rack waiting to be brought that or just didnt lay them out right an dheat got to them or they was just a cheap set of wires
sounds like poorly constructed wires. try not to lay them on the exhaust manifold.
You get what you pay for. Get some high performance wires, they are a lot better. I use them on everything, even my boat. They are made a lot better and worth the extra money. They will not go bad for a long time. When you install them be sure to keep them away from the exhaust.
If your sure the connectors snapped in properly, then I would try and exchange them at the store I bought them from. I actually have one set of plug wires that are gauranteed for the life of the vehicle. You can actually measure the resistance of each wire to make sure it's about right for that length of wire. Typically it's about 1,000 ohms per foot for resistance type wires. Use the Multimeter shown below from Sears. However, the wire could still be bad even if the resistance measures correctly.



http://www.sears.com/shc/s/search_10153_
Hop over to your dealer and get the right wires for your vehicle. As you know the originals went for many miles. I will not get into the after market scene or I might get bard from this site.