How To Crimp Wire Disconnects


Crimping wires into the wire disconnects but don’t know how to or what to use? Then you came to the right place! In this article we are going to tackle on how to crimps wire into the wire ends crimp.

But first what is crimping? Crimping is by joining pieces of metal by deforming it to hold or to lock on to each other using a wire terminal crimp tool.

So basically, we should be deforming some metals from its original shape or design to lock wires in place to make it safe for us to work on wires without the use of solder.

wire disconnets

How do we do it?

We do it with the help of a variety of wire terminal crimp tools to make the job easier and fast. Crimp termination can be one of the quickest, dependable and rugged method of wire termination.

However, if the crimping of wire terminal is not done correctly, the quality of the work may be affected. It is important for us to use the right size of wire and the right wire terminal crimper so we can save time and money for our wiring projects.

wire terminal crimping tool kit

For over at least a century, soldering (process of melting and putting solder into a joint) wires has been commonly used, however in the middle of 20th century crimp terminals came to use.

Wire disconnects were introduced by AMP Incorporated (now TE Connectivity) in 1953, and the Cannon brothers experimented with machine contacts integrating crimp barrels in 1957.

In the 1960’s, several standards for wire ends crimp were published this includes MS3191-1, MS3191-4 and MIL-T-22520 in 2010, the MIL-DTL-22520 has become the standard for crimp terminals and connectors.

What is a wire terminal crimper?

A wire terminal crimper is the tool that will helps us crimp wires into the wire disconnects it is normally performed by putting the cable connector terminals into the terminal crimpers. So, what are the wire terminal crimping tools?

ferrule tool

Types of Wire Terminal Crimper:

  1. Hand Crimpers

These handheld wire terminal crimpers are suitable for small wire. Many kind of this type of wire terminal crimp tool also have wire cutters that can cut and strip wires so that’s a 3 in 1 tool as well!

They have this color coding design on the side of the tool. Normally it has 3 or 4 crimping terminals, so you know what to use for proper crimping of the wire disconnects.

This type of tool has a wide variety of designs depending on the brand or maker of the tool. Mostly this type of tools has a ratchet style design for non-insulated (no outer cover) and insulated (with outer cover) wire terminals.

There are also tools for heat shrink connectors. You just have to use a heat gun for the wire terminal or connector to shrink to the size of the wire.

Same goes for the ferrule crimping tool which is almost the same process but instead of crimping it at the end of the wire ends crimp, we crimp it at the metal part.

The best benefit of using terminal crimper is that there is no guessing involved because of the color coding or the size identification indent on the side of the tool and the color of the wire disconnects.

You will be crimping cable connector terminals like a professional electrician.

wire terminal crimper

  2. Hydraulic Wire crimper

This type of wire terminal crimping tool is also used to crimp a wire terminal or connector by joining the stripped end of the wire and the wire terminal or connector using hydraulic.

There are two types of hydraulic crimper tool. Hydraulic crimper tools can crimp wire terminals and connector with a crimping force of 6 tons up to 15 tons.

  • Hand HydraulicCrimper tool – like the name suggests this is a type of hand crimpers too but with the help of hydraulic fluid mechanism for transferring force to the jaws of the tool from the user.

This is much more powerful than other handheld wire terminal crimper and can work with much thicker wire and less stress to the user than other manual crimp tool.

Lug crimping tool

  • Size ranges from 22 AWG (American wire gauge) up to 24 AWG wire and crimps
  • Easy tool to use and light-weight

Power Hydraulic Crimper Tool – this type of hydraulic crimp tool is usually used where a full cycle mechanism is needed for the consistent shut heights of the wire terminal or connector.

Industrial application is where this tool is mainly used like. Most design of this tool is battery operated.

power hydralic crimper tool

  • For utility power cable use
  • Range can go as far as 750 MCM (Thousand Circular Mils)


What are the advantages of the new age hydraulic crimper tools?

  • It is easier to handle and use because of its lightweight design
  • Very durable
  • Less physical stress on the user
  • There will be no repetitive motion injury
  • Faster crimping
  • Precise crimping of the crimp wire terminals or connectors
  • Much better output of number of connections per day

  3. Hammer Crimper Tool

This type of crimp wire terminal tool uses a hammer to deform or compress the wire terminal or connector.

hammer crimper tool

  4. Automatic Crimping Machine

This crimping tool or machine is fully or semi-automated and crimps wire terminals and connectors faster than a human can.

pneumatic crimper tool

  5. Other Wire Terminal Crimp tool

  • Crimping Tool with Dies – this tool has built-in dies or interchangeable dies this need different sets of dies for each terminal or connector. This tool is color coded too but some others have size identification indent.

crimping tool die set

  • Crimping Tool with Cutter – this tool is designed with a wire cutter that cuts wires from 10 up to 22 AWG. This tool can crimp wire terminals or connectors for insulated and non-insulated types. The style of this tool is compact that is why it is easy to handle and carry.

crimping tool with cutter

  •  – This set is for multiple crimping tools, it can be used with different terminals or connectors because of its Ratchet style crimping tool with interchangeable dies. The dies of this set have color coded or size identification indent so that there will be no mistake in crimping the right size of wire, it also have a tool box with a screwdriver.

Crimping Tool Jaws

  • Crimping Tool Jaws – This one has interchangeable jaws. A screwdriver is used to remove or connect the interchangeable jaws with built-in dies. This type of tool will help you to have more options in crimping different wire sizes and terminal or connector types.

Types of Jaw:

  • Kearney Style Jaw
  • W-style Jaw
  • U-style Jaw

We can use theses jaws for insulated, non-insulated, Open barrel, Small Cord end, Large Cord end terminals and Cable connector.


There you go with the different kind of wire terminal crimper for crimping wire disconnects!

So how do we use it the right way? For most of the handheld and hydraulic crimp tools, the crimp barrel and the wire to be used must be the right size for us to continue the process.

Then, to maximize the cross-sectional contact, the stripped wire must be inserted into the wire terminal completely with the end of the wire flush with the exit of the terminal.

Finally, to compress and reshape or deform the wire terminal we use the handles or the trigger button (for the battery operated wire terminal crimp tools) of the crimp tool.

What if they are loose at the edges?

The resulting connection of the terminal may seem loose at the edges, but this is what we wanted so that the wires will not have sharp edges that can cut the outer strands. If done properly, the middle of the crimp will be swaged.

On the other hand, the crimp-on connectors are attached by putting the stripped end of the wire into a portion of the connector, and then we deform by crimping (compressing) it tightly around the wire.

A crimping tool like crimping pliers are used to accomplished this. The right idea to crimped connectors is that it should be gas-tight (not penetrable by gas or air) sometimes called as cold weld.

Metals in the crimped connections are highly resistant to vibration and thermal shock due to the elastic nature of the metals. To hold the cable in place, we must create a high degree of static friction between the surrounding connector we must deform or crimp the metal of the connector way past its yield point to cause that friction.

Making a crimp connection is very simple, but there will be no room for mistakes because if you made a mistake the wire crimp terminal cannot be used again, and you have to start from the beginning again.

There are two classes of wire crimps:

  • Closed barrel crimps – this type ofwire disconnects have a cylindrical opening for us to insert a wire and using a wire terminal crimper we have to deform the circular cross section of the cable connector terminals for the wire to stay in place. Vibration is less resilient to this kind of method.

closed barrel crimp

  • Open barrel crimps – this type of wire disconnectshave “ears” of the metal that are shaped like a V or U, before swaging the wire to the wire ends crimp we have to fold the ear like metal part of the cable connector terminals to the wire so the wire stays in place. This type claims to be an easier choice because it avoids the need to funnel stranded wire into the small opening of the wire terminal.

open barrel crimp


For the hammer type crimp tools, first we need to adjust the crimping ram head to the size of the wire and wire disconnects. Then we are going to place terminal in the jaw of the crimper then put the end of the stripped wire in the wire terminal.

When the tool is in solid surface (ground or table), strike the ram with a hammer when the impact of the hammer feels solid the crimping is complete.

What are the two types of crimping style?

  • Indent crimping style – we use indent crimping style for fine stranded and compacted conductors, this is a very easy style of crimping and the end results are great pullout resistance and very good electrical performance.

ident crimping

  • Hexagonal crimping style – hexagonal style is very common and end results are equally strong mechanical connection.

The biggest advantage of hexagonal style over the indent style is that the force of the crimping is coming from all directions while crimping and that prevents any damage to the conductors.

This crimping style is an industry standard for copper and aluminum cables up to 1000MCM and like the indent style it has great pullout resistance and very good electrical performance too.

Hexagonal crimping

Benefits of knowing how to crimp wire terminals or connectors the proper way:

  • Can save time
  • Cost efficient (money saver)
  • Can stop the wire terminal from corrosion
  • Quality wise than soldering
  • Provides good and safe electrical connection
  • High quality crimp
  • Manpower efficient

Important things to know about crimping wire terminal or connector:

  • Size of the wire terminal or connector
  • Size of the wires to be used
  • Tools that is going to be used
  • Wire strands should be completely stripped clean
  • Do not over crimped wire terminals or connectors
  • Strip wire according to the size of the wire terminal or connector
  • Stripped wire should be properly connected to the metal part of the terminal or connector
  • Double check if the wire and the wire terminal or connector is not loose and will not fall apart

Note:  Never ever use pliers, needle nose pliers, hammer (without the use of the hammer crimp tool) or other tools other than crimp tools to crimp your electric wire terminals or connectors.

Using such tools will result in a loose connection that will result in an open circuit or wiring failures and will cost you more for back jobs due to wrong crimping of wire terminals or connectors.

Never test the tools with your finger or any part of your body to avoid injuries. Never tests the tools with other objects as it may damage the crimp tool.

So there you have it guys!  Now, you know the correct way and process of how to crimp wire disconnects. I hope that in this chapter, you gained knowledge and will help you in the future electrical jobs or project that you might have, may it be at your own home or others. Keep safe everyone!

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