A hydraulic crimping tool, also known as a hydraulic crimper or hydraulic crimping pliers is a crimping tool that uses hydraulic pressure to crimp a connector to form an electrical connection. A hydraulic crimping tool consists of a pair of handles, a hydraulic pump mechanism along with jaws or interchangeable dies. The stripped wire is inserted into the crimp connector which is then positioned into the jaws or appropriate die cavity of the hydraulic crimper. The handles of the crimp tool are then squeezed together activating a hydraulic pump mechanism causing the hydraulic fluid to be pressurized which forces the dies to close around the crimp connector to create a secure crimp. Once the connector is fully crimped the hydraulic pressure is relieved and the handles of the tool are released allowing the jaws or dies to open and the fully crimped connector to be removed.

Another type of hydraulic crimping tool is the battery-operated hydraulic crimping tool which works on the same principles as a manual hydraulic crimping tool but incorporates a rechargeable battery and motor to generate the hydraulic pressure required for crimping. The advantages of having a motor in a crimp tool means there is less physical effort required by the operator and eliminates the need for manual pumping and additional tooling. Battery operated hydraulic crimpers with their cordless design are portable and ideal for use in fieldwork and installation applications that often take place in remote areas where there may not be a power supply including electrical contracting, automotive and telecommunications

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Hydraulic crimping tools provide consistent and uniform crimps and so reduce the number of faulty electrical connections. Using a hydraulic system allows high force to be applied with minimal effort from the operator allowing larger cables or wires to be crimped. Hydraulic crimping tools often have built in safety features including pressure release valves to prevent over crimping. Battery operated hydraulic crimping tools may also have LED indicators to show battery life, crimping status or errors