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A guide to crimping

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Caravan Talk


A guide to crimping


Tools needed.


A ratchet crimp tool (The opinion of experts say cheap non-ratchet crimp tools are not suitable)

Wire strippers.

Crimps : Buy good quality crimps.

(If the crimps are stamped with digits they should be good quality)

Stranded wire is best so if using solid wire, its better to solder, not crimp.

When buying a ratchet crimping tool note the wire gauge they are designed to crimp,

and make sure there is a release lever on the tool.


You should be aware that not all crimping tools are manufactured to the correct standard, where the colour

coding and size stamp are incorrect.

The standard colours from jaw end to hinge should be red, blue, yellow as shown below.






In the photograph above, the tool I used for this article has the following die dimensions with the tool handles closed.

All sizes approximated.

Yellow 6 x 3 mm.

Blue 5.5 x 3 mm

Red 4 x 1.5 mm.


If you follow the procedures below, all crimps will result in a good quality connection. 


First, strip the wire so the strands are the length of the crimp barrel






With the tool jaws open, fitting the narrow part of the crimp in the jaw groove so that it is held there

ensures the  correct groove for the crimp.






Next, position the crimp so insulation is equal on both sides of the tool.

Close the handles to the first ratchet click so that the crimp is held in the tool.






Twist the wire strands just enough to hold them together then insert the wire into the crimp so that

 wire strands at the terminal end of the crimp are visible. Note the position of the gap in the crimp barrel.

With the right wire and crimp size the insulation of the wire should be too large a diameter to

enter the barrel of the crimp.






Squeeze the handles together to form the crimp and to compress the crimp metal. It should require effort

to squeeze the handles together until the tool releases.






Some other crimped wires.





To test the connection, try to pull the terminal off with your hands.


As with everything, practise makes perfect, after which you will be able to achieve successful crimps

following the procedures above.


To sum up :-


1. With the right wire and crimp size the insulation of the wire should be too large a

     diameter to enter the 'barrel' of the crimp.


2. With the tool jaws open, fitting the narrow part of the crimp in the jaw groove so that it is held there

      ensures the correct groove for the crimp.


3. Through testing I found that by having the gap on the crimp barrel 

      as in the photograph in PIC 5 above produced good results.



 Additional Information :-


Normal trailer wiring is 1.5mm (brake lights, etc.) and the heavy duty wiring is 2.5mm

(caravan battery charging, fridge)  2.5mm is rated at 30 Amps.


The generally adopted standard for crimps is :-

Red Insulation 0.5 - 1.5 square millimetres  (22-16 AWG)

Blue Insulation 1.5 - 2.0 square millimetres  (16-14 AWG)

Yellow Insulation 4.0 - 6.0 square millimetres  (12-10 AWG)


AWG is explained by clicking  HERE then see ELECTRICAL - Everything about cables.


My thanks for advice from

Gordon, Rodders53 & Kelper.


Edited by BOAC
Tool jaw measurements added
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