Bundle tie Bundle tie Group tie $^{1}$/2" maximum with normal hand pressure Figure 4-86.  Staggered splices in wire bundle. Figure 4-87.  Slack in wire bundle between supports.  Figure 4-85.  Recommended number of twists per foot. Figure 4-84.  Group and bundle ties. #22 #20 #18 #16 #14 #12 #10 #8  #6  #4 10 10 9 8 7 $^{1}$/2 7 6 $^{1}$/2 6 5 4 10 10 8 $^{1}$/2 7 6 $^{1}$/2 6 5 $^{1}$/2 5 4 3 2 Wires 3 Wires When specified on the engineering drawing, parallel wires  must be twisted. The most common examples are: Twist the wires so that they lie snugly against each other,  making approximately the number of twists per foot as listed  in  Figure 4-85.  Always check wire insulation for damage after  twisting. If the insulation is torn or frayed, replace the wire. Spliced connections in wire groups or bundles should be  located so that they can be easily inspected. Splices should  also be staggered so that the bundle does not become  excessively enlarged.  [Figure 4-86]  All noninsulated splices  should be covered with plastic, securely tied at both ends. Single wires or wire bundles should not be installed with  excessive slack. Slack between supports should normally not  exceed ½ inch. This is the maximum it should be possible  to deflect the wire with normal hand force. However, this  may be exceeded if the wire bundle is thin and the clamps  are far apart. But the slack should never be so great that  the wire bundle can abrade against any surface it touches.  [Figure 4-87]  A sufficient amount of slack should be allowed  near each end of a bundle to: Bends in wire groups or bundles should not be less than  ten times the outside diameter of the wire group or bundle.  However, at terminal strips, where wire is suitably supported  1.  Wiring in the vicinity of magnetic compass or flux  valve, 2.  Three-phase distribution wiring, and 3.  Certain other wires (usually radio wiring). 1.  Permit easy maintenance; 2.  Allow replacement of terminals; 3.  Relieve mechanical strain on the wires, wire junctions,  or supports; 4.  Permit free movement of shock and vibration-mounted  equipment; and 5.  Permit shifting of equipment for purposes of  maintenance. Spliced Connections in Wire Bundles Slack in Wiring Bundles Bend Radii 4-52