Splicing is permitted on wiring as long as it does not affect  the reliability and the electromechanical characteristics of  the wiring. Splicing of power wires, coaxial cables, multiplex  bus, and large-gauge wire must have approved data. Splicing  of electrical wire should be kept to a minimum and avoided  entirely in locations subject to extreme vibrations. Splicing  of individual wires in a group or bundle should have  engineering approval, and the splice(s) should be located  to allow periodic inspection. Many types of aircraft splice connector are available for  use when splicing individual wires. Use of a self-insulated  splice connector is preferred; however, a non-insulated  splice connector may be used provided the splice is  covered with plastic sleeving that is secured at both ends.  Environmentally sealed splices that conform to MIL-T-7928  provide a reliable means of splicing in SWAMP areas.  However, a non-insulated splice connector may be used,  provided the splice is covered with dual-wall shrink sleeving  of a suitable material. There should be no more than one splice in any one wire  segment between any two connectors or other disconnect  points. Exceptions include when attaching to the spare  pigtail lead of a potted connector, when splicing multiple  wires to a single wire, when adjusting wire size to fit  connector contact crimp barrel size, and when required to  make an approved repair.  Splices in bundles must be staggered to minimize any  increase in the size of the bundle, preventing the bundle from  fitting into its designated space or causing congestion that  adversely affects maintenance.  [Figure 9-132] Wiring must be routed away from high-temperature  equipment and lines to prevent deterioration of insulation.  Wires must be rated so the conductor temperature remains  within the wire specification maximum when the ambient  temperature and heat rise related to current-carrying capacity  are taken into account. The residual heating effects caused by  exposure to sunlight when aircraft are parked for extended  periods should also be taken into account. Wires, such as  those used in fire detection, fire extinguishing, fuel shutoff,  and fly-by-wire flight control systems that must operate  during and after a fire, must be selected from types that are  qualified to provide circuit integrity after exposure to fire for  Wires and wire groups should be protected against chafing or  abrasion in those locations where contact with sharp surfaces  or other wires would damage the insulation, or chafing could  occur against the airframe or other components. Damage  to the insulation can cause short circuits, malfunction, or  inadvertent operation of equipment.  The minimum radius of bends in wire groups or bundles must  not be less than 10 times the outside diameter of the largest wire  or cable, except that at the terminal strips where wires break  out at terminations or reverse direction in a bundle. Where  the wire is suitably supported, the radius may be three times  the diameter of the wire or cable. Where it is not practical to  install wiring or cables within the radius requirements, the  bend should be enclosed in insulating tubing. The radius for  thermocouple wire should be done in accordance with the  manufacturer’s recommendation and shall be sufficient to  avoid excess losses or damage to the cable. Ensure that RF  cables (e.g., coaxial and triaxial) are bent at a radius of no less  than six times the outside diameter of the cable. device, except when attaching to the pigtail spare lead of a  potted termination device, to splice multiple wires to a single  wire, or to adjust the wire sizes so that they are compatible  with the contact crimp barrel sizes. Figure 9-131.  Recommended number of wire twists per foot. Bend Radii Spliced Connections in Wire Bundles Protection Against Chafing Protection Against High Temperature Figure 9-132.  Staggered splices in wire bundle. 9-80 Splices should not be used within 12 inches of a termination   22 20 18 16 14 12 10 8 6 4 Gauge # 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