Cable Cutters

The difference between these two types of powered cutters comes down to how they generate force and how they are used.

Cordless cable cutters have a battery-powered motor, which is combined with a built-in 2-stage hydraulic system to drive the cutting blades. Battery-powered cable cutters are used because of their portability and convenience, making them an ideal power tool for on-site work where mobility is important. They are fast, easy to use and reduce manual effort, because they only require the operator to press the trigger and the cutting mechanism operates automatically, however they are limited by battery life and we always recommend carrying a spare battery to enable continuous work.

Hydraulic cable cutters, on the other hand, rely on hydraulic pressure that is generated either manually via a hand or foot pump, or via a powered hydraulic system. Manual hydraulic cutters don’t require batteries but are slower to operate and require some pumping effort from the operator (depending on the pump system used).

There can sometimes be a misconception that cordless cable cutters cannot generate similar cutting forces to hydraulic cable cutters, which is not true in the modern day, due to advancements in battery technology, as some cordless cable cutters can cut through armoured cable just as easily as hydraulic cutters. 

2-stage hydraulic systems are used widely in powered crimping and cutting tools, and provide two levels of hydraulic pressure and flow, in order to improve both speed and power during operation. 2-stage systems are used because a single-stage system would either be fast but weak, or powerful but slow. The two phases are -

1. A low-pressure, high-speed stage. At the start, the system delivers high fluid flow at a lower pressure, which allows the tool to move quickly toward the material, which reduces idle time and improves efficiency.
2. High-pressure, low-speed stage. Once resistance is met (e.g. when cutting a cable), the hydraulic system automatically switches to a lower flow that applies a much higher pressure, providing the force required to complete the cut or crimp without requiring excessive manual effort from the operator.

In short, no, although there are some VDE-certified cutters that can.

Powered cable cutters should not be used to cut through live cable unless it is specified that they can. This is because if the operator cuts through a live cable it can cause a potentially fatal electric shock, an arc flash or damage the cutting tool.

Some cable cutters are VDE-certified and can safely cut through live cable up to 1000 volts, however it is always recommended to cut through unpowered cables where possible.

Modern battery management systems (BMS) in battery-powered cable cutters ensure that the battery maintains consistent performance for most of the charge cycle, enabling the cutter to deliver near-full force until the battery reaches a low threshold. As soon as the BMS recognises that the battery is running out of charge, the performance of the tool will either suddenly slow down or completely stop, which protects the longevity of the battery.

Some factors to look out for when choosing the correct battery for the job, include -

• Battery capacity (Ah) - The higher the ampere-hour, the more power the battery can output in an hour.
• Battery age/condition - Worn batteries lose efficiency by internal chemical changes, which is a natural and unavoidable process, although modern lithium-ion batteries resist this much better than nickel-metal hydride (NiMH) batteries.
• Temperature - Colder conditions reduce performance by slowing down the electrochemical processes in a battery that produce power. Anything below -20°C can severely impact the performance of a battery.
• Workload - Cutting through thicker gauge or armoured cables naturally demands more power and will drain the battery quicker than if it was being used on smaller gauge cable.

Hydraulic pressure determines how much force a cable cutter applies to its blades, which directly affects the size and type of cable it can cut. This principle is based on Pascal’s Law, which states that pressure applied to a confined fluid is transmitted equally in all directions.

In real life terms this means that force is generated when hydraulic fluid is pressurised against a piston inside a cylinder. The pressure acts across the piston’s surface area, so higher pressure or a larger piston produces greater cutting force at the blades, which is transferred through to them via a mechanism in the cutting tool.

The difference mainly comes down to accessibility and cutting strength. 

Open-jaw cutters have a gap in the head that allows the operator to quickly and easily place the cable at the jaws of the tool, so that it can be cut quickly. This is ideal for cutting work in tight spaces, when working with cable overhead or carrying out repetitive cutting. 

Closed-jaw cutters have an enclosed head that requires the cable to be fed through the blades before cutting. This style of cutter provides a more even cutting pressure around the cable to create a cleaner cut, and has a higher cutting force than an open-jaw cutter, making it a better choice for cutting armoured cable, however it is slower to operate than an open-jaw cutter.