# Twisted pair cable/ Shielded twisted pair

#### Lundwall_Paul

Joined Oct 18, 2011
226
Anyone have references to Twisted pair cable/ Shielded twisted pair? I am looking for general guide lines as to when twisted pairs should be used, and how shields should be used. I have used RS-485 shielded twisted pairs just dont understand why one end of the shield is grounded but not the other end. I suspect it is to prevent ground loops, but I see in other applications where the shield is tied at both ends.

#### crutschow

Joined Mar 14, 2008
25,269
For low frequency shielding (such as for 50-60Hz) you can connect the shield at one end to minimize ground loops. For high frequency (RF) shielding the shield should be connected at both ends.