When should I use shielded CAT5e cables from Wholesale UTP CAT5E Cables Manufacturers? If you want to ensure maximum speed and efficiency from the network under any circumstances, you may need to use shielded CAT5e cables. It is difficult to know when and where you will encounter enough EMI to cause problems, but if you use a shielded CAT5e cable first, you don't have to worry about tearing the...