Manual and Hydraulic

• Most crimping tools are categorized by how they apply power to the wires. Primarily, there are manual and hydraulic tools. You can apply force with manual tools by squeezing the handles. Hydraulic crimping tools vary; some work remotely, some are battery-actuated and some are hand-based. The best tool depends on the wire. Smaller wires may be better fitted to the manual crimping tool, which has more maneuverability, while larger wires are more compatible with hydraulic versions. Hydraulic versions also require more maintenance.

Dies

• Many crimping tools require different "dies" or attachments to fit different sizes and shapes of connectors. The best tools are dieless and can automatically work with a variety of different connectors. However, this is only practical in a certain range of connectors; beyond that you will need to use dies. A die-based tool with be able to be used with a much wider variety of connectors and therefore wires. Choose based on what type of wire you will be working with most often.

Rotation

• Most hand-based crimp tools offer some kind of rotation along the crimping head. This allows the tool to access harder-to-reach wires and crimp more easily, and can be very useful for electricians who are dealing with wire that is already installed. There are different levels of rotation. Some may only rotate halfway, while others may rotate 360 degrees. The best type of rotation--if you need it--is the full circle, which allows the most maneuverability.

Relief Valves

• Relief valves are used on crimping tools to stop the tool from compressing too far. This means that if you squeeze the handle too hard or apply too much pressure with a hydraulic system, the valve will cut off the force before the wires are damaged. Good crimping tools always have relief valves.

Additions

• Many crimping tools come with additions attached as extra features. A popular addition is a wire cutter and wire stripper mechanism, which does not take up much room and can be very useful. These additions can make the crimping tool even more useful and should be valued accordingly.