Views: 73 Author: SEILSOUL Publish Time: 2019-02-25 Origin: Site
If you know what wire size you have, you will also need to work out what you need to connect to. There are many, many variations of crimp, but there are a handful of very common ones, most shown in the image. Crimps designed to fit to threaded fasteners can be simply specified by the bolt size (e.g M4/ ¼”). Others may have different names dependent on the industry and manufacturer (eg lucar, faston, ¼” blade). Critical to getting a good joint will be the quality of the crimp- it is difficult to get a good, long lasting joint with a poor quality wire terminals crimp connectors.
Terminals are available with a number of different plating options to give corrosion protection and for other technical reasons (such as low contact resistance). I would avoid any crimp (if at all possible) that doesn’t have a plating so that you don’t have to re-visit it in the future to clean it of corrosion. This will be especially important in the more corrosive atmosphere like those found on a boat. The most common available plating is tin, and this will be suitable for most needs. Silver and gold are also common in certain applications, but are usually used in low current/ signal applications where a minimum resistance across the joint is needed.
If using pre-insulated terminals the better quality connectors have a metal sleeve to grip the wire insulation, the lower quality parts don’t have this. The image of the sectioned crimps shown make this obvious, but to determine this when not sectioned, look down the barrel of the crimp from the wire entry end. You will see metal to almost the end of the crimp in a quality part, but it will stop short in cheaper parts.
All terminals will be sold with a defined wire size range- this should be listed on the packet, but if not and you are using pre-insulated parts you can tell by the colour of the sleeve. The generally adopted standard is:
Red Insulation 0.5-1.5mm2 / 22-16 AWG
Blue Insulation 1.5-2.5mm2 / 16-14 AWG
Yellow Insulation 4.0-6.0mm2 / 12-10 AWG
There are other colours around, but you are unlikely to come across these unless you are doing industrial, aerospace or military work.
These parts are made in one of two ways- sheet formed or tube terminals. The sheet formed ones are manufactured by cutting the material out of flat sheet and then shaping to make a tube on one end. Better quality ones of this type will have thicker material and the seam brazed. Tube terminals are manufactured by cutting a piece tube to length, flattening one end and punching a hole. The tube type tend to be heavier duty and therefore are more common in the larger sizes- for example you might encounter these on a starter motor feed.
This type of crimp has by far the biggest amount of variation tending to be the type used in connector housings. Of the many thousands available, by far the most common that you are likely to come across are of the blade type, of these the ¼” blade are the most common with 1/8” (3.2mm) and 3/16” (4.8mm) also frequently encountered. You will find these connectors widely used in cars, domestic appliances, Hi-Fi equipment etc.
You may well find different types on your car for other applications- if you need to replace these good auto-electrical suppliers can often provide you with a kit of parts. These types will often need a very specific tool to crimp correctly.
These are most commonly encountered in military-spec connectors, but may also be encountered in industrial connectors, RF connectors and high quality D-Types. They are manufactured by turning parts from rod and hence are almost invariably round.
There are many other types of crimp around, most of which have specific applications and you are therefore unlikely to encounter in day to day life.
A large proportion of crimps are available in a form that enables automatic crimping on a specialist machines- normally a strip or carrier supplied on a reel. These can be crimped with hand tools, but will need to be removed or cut from a carrier strip. Other terminals are supplied as ‘loose piece’- individual parts supplied usually in bags or boxes.