There seems to be alot of groomers with cord problems recently. Many think the cords are made of junk, but really they are not. All the twisting and pulling on the cords during a groom can break the wires on the cord right where the cord enters the clipper body. Then as you move the clipper around during a groom its starts to short out momentarily which can drive you insane. There is an "Old School" trick you can use that saved our cords from breaking and shorting out. In fact, once we did this little trick we never had a cord problem again unless a dog bit through it.
If your clipper has stiff a "hanger" on the back like Andis or Wahl your in luck. Swivel hangers like on LAube and Oster clippers aren't rigid enough to do this trick properly, but it can be done. All it takes is a zip-tie! You zip-tie your cord to your clipper hanger to prevent the cord from bending or twisting at the clipper and it won't break. Thats where the break in the cord is usually at....right where the cord enters the clipper. So when you prevent it from bending in the thick part of the cord where it goes in the clipper, and force it to bend where the cord is flexible, it won't break. We did this to all our Andis clippers a few years back and haven't had a cord problem since. Below is a picture of an Andis clipper, and a Wahl clipper with the cords "zip-tied" to the hanger.
Now your thinking "If I zip-tie the cord to my hanger, I won't be able to hang my clipper up anymore" Don't worry you still can. We use a "key ring" from the hardware store that cost less than a dollar. We thread it though the hanger like you would a key and it gives us a better hanger to hang the clipper up with. Below is a picture of a 1 1/2 inch key ring.
Just attach this key ring on the hanger, either side of the cord that is zip-tied to it, and your good to go. Hope this helps with your breaking cords all the time.
Have a great day grooming and read those labels!