TM 1-1500-204-234 b. Replacement    Criteria.    Wiring  shall  be  replaced when found to have any of the following defects: · It becomes unmanageable due to splice or number of splices. · The primary insulation has been broken. · The outer insulation is weather-cracked. · It  is  known  to  have  been  exposed  to  battery  acid  or the   insulation   is   beginning   to   deteriorate   due   to suspected exposure to battery acid. · It shows evidence of overheating. · The   insulation   has   been   saturated   with   engine   oil, landing gear lubricant, hydraulic fluid, or solvent. · It shows evidence of having been crushed or severely kinked. CAUTION Cleaning   agents   or   preservatives shall  not  be  used  to  minimize  the effects of corrosion on or deterioration of wire shields. Further damage may occur. · The   metallic   shield   on   shielded   wire   is   frayed   or corroded. · The   insulation   sleeves   placed   over   wire   splices   or terminal lugs show evidence of breaks, cracks, dirt, or moisture. c. Wire   Sizes.        Wire    is    manufactured    in    sizes according   to   a   standard   known   as   the   American   Wire Gauge (AWG).  Wire size may be determined by using a wire gauge as shown in figure 3-1.  This type of gauge will measure wires ranging in size from number 0 to number 36.    The  wire  to  be  measured  is  inserted  in  the  smallest slot that will just accommodate the bare wire.  The gauge number corresponding to that slot indicates the wire size. The  slot  has  parallel  sides  and  should  not  be  confused with the semicircular opening at the end of the slot.  The opening simply permits the free movement of the wire all the way through the slot. Figure 3-1.  Wire Gauge NOTE Gauge numbers are useful in comparing   the   diameter   of   wires, but  not  all  types  of  wire  or  cable can  be  accurately  measured  with  a gauge.      Large   wires   are   usually stranded to increase their flexibility. In such cases, the total area can be determined  by  multiplying  the  area of one strand (usually computed in circular    mils    when    diameter    or gauge   number   is   known)   by   the number  of  strands  in  the  wire  or cable. d. Wire Identification.  To make maintenance easier, each interconnecting wire and cable installed in aircraft is marked with a combination of letters and numbers which identify  the  wire,  the  circuit  it  belongs  to,  its  gauge  size, and  other  information  necessary  to  relate  the  wire  to  a wiring    diagram.        This    marking    is    called    the    cable identification code.  Details of the code are given in MIL- W-5088.  Wire received from the manufacturer is printed with the manufacturer's code designation is a light green color at intervals of one to five feet, the MS number and dash number of the wire, and a one-, two-, or three-digit number  indicating  the  color  of  the  basic  wire  insulation and the color of the stripes (if present).  The color code is as follows: Black 0 Blue 6 Brown 1 Violet 7 Red 2 Gray 8 Orange 3 White 9 Yellow 4 (includes also Green 5 uncolored insulations) Change 3 3-3