Pick the wire. A splice is chosen by the conductor it has to hold, and both wires going into it must be inside the same range. For a multi-wire splice (SolderGrip, SolderSleeve, MiniSeal stub) give the TOTAL cross-section of every wire in it; for a coaxial kit, the RG cable; for a repair sleeve, the wire’s outside diameter.
Wire size, colour and the splice that fits it
A sealed butt splice, named part by part. The adhesive ring is what makes it environmental — it has to flow.
The same size code on real parts, drawn to one scale — the colour band tells you the wire range before you read the number.
The colour is the splice, not the wire. Red, blue and yellow are the long-standing size code on a heat-shrink butt splice and the fastest check you have that the right one is in your hand.
M39029 contacts for a splice housing
These are the contacts that go into a splice housing, not butt splices. They are here because the housing is chosen by contact size and it is the one number that is never on the splice itself.
REFERENCE ONLY — not authorized for maintenance, repair or return-to-service. A splice is a crimp: the tool, the die and the positioner are named by the maintenance task or the wiring practices manual and are not chosen from a dimension table. A sealed splice is only sealed if it is shrunk to the manufacturer’s profile with a controlled heat gun — the adhesive ring must flow. Where a splice is in a fuel zone, a fire zone or a pressurised compartment, the task, not this page, says whether a splice is allowed there at all.