DC power supply modules Control terminals 6 6.7 Design of the cables ƒ The cables used must comply with the approvals required for the location (e.g. UL). ƒ The effectiveness of a shielded cable is reached by: – Providing a good shield connection through large-surface shield contact. – Using only braided shields with low shield resistance made of tin-plated or nickel-plated copper braid. – Using braided shields with an overlap rate > 70 % and an overlap angle of 90 °. – Keeping unshielded cable ends as short as possible. The following connections need not be shielded: ƒ 24 V supply ƒ Digital signals (inputs and outputs) 6.7-2 EDS94SPP101 EN 3.1-04/2007