C.K Tools pliers review: RedLine VDE

The T3973-160 and the T3910-210 are the two RedLine VDE pliers from C.K Tools. The first cuts conductors by shearing in a 160 mm format; the second, at 210 mm, combines gripping, stripping, cutting and a LOOP eyelet.

I carried them in my tool bag during my documented work, with a stop in the workshop for two precise tests: a bundle of 2.5 mm² conductors on the cable cutter and a continuous impact test on the multi-tool.

What I wanted to know: does shear cutting preserve the strands, does stripping stay clean on copper, and what exactly does the VDE marking on these two references guarantee.

Two C.K Tools RedLine VDE pliers, two jobsite motions

Both references belong to the RedLine VDE range, the insulated tool line C.K Tools intends for live working. I have already told the story and the ranges of the brand in my C.K Tools review; here I stick to the two pliers.

The T3973-160 is a cable cutter: it slices the conductor to shorten it before connection. The T3910-210 is an installation multi-tool: it grips, strips, cuts and forms eyelets.

The choice between the two therefore comes down to the dominant motion, not the stated length. An electrician who mainly prepares panels and boxes does not do the same plier work as an electrician who cuts a lot of conductors at the end of a pull.

The manufacturer lists the range as T3973A 160 for the cable cutter; the spelling T3973-160 is what appears on the commercial datasheets. The multi-tool is listed as T3910 210 in the brand’s catalogue.

Cable cutter T3973-160: cutting by shearing

The cable cutter measures 160 mm in total. It is the compact format of the range: it slips in where a 200 mm plier cannot spread its handles, at the bottom of a flush-mounted box or in a cluttered luminaire housing.

Its mechanism relies on shearing: two crescent-curved blades slide against each other and slice the conductor in the hollow of the jaw. The manufacturer claims a clean cut and a blade profile that also serves for stripping.

1 Crescent-shaped cutting blades Crescent-shaped cutting blades

T3973-160 cable cutter

The jaw profile explains the clean cut claimed on connecting conductors.

In the workshop, I cut through a bundle of 5 to 6 copper conductors of 2.5 mm². Without forcing on the handles, the insulation stayed intact and the cut flat, ready to be threaded into a terminal block.

The straight cross-section changes everything at insertion: a crushed conductor slides in badly into a terminal, especially in Wago connectors designed for stranded and solid wire.

Before cutting a conductor in an installation, isolate the circuit, secure it against reconnection and verify the absence of voltage. The factory VDE rating is no permission to cut a live wire.

Once the circuit has been isolated, secured against reconnection and proved dead, these three cutting movements are straightforward. The VDE marking never replaces safe isolation.

What shearing changes for preparation

A classic diagonal cutter works differently: it crushes the metal on both sides of the cut. The strands flatten, the insulation gets marked, and the end of the conductor becomes difficult to insert into a terminal.

The crescent-shaped shearing holds the cable in the hollow of the blades before separating it. The manufacturer claims a clean cut, with no fraying: that is what the test on the 2.5 mm² bundle shows.

The arms carry dual-material handles with anti-slip guards. The hand does not slip when a hard squeeze is needed on a stubborn conductor.

What the cutter cuts, and what it does not cut

The range page specifies this: this cable cutter is intended for copper and aluminum. A conductor of another metal is not covered by this tool; a cutter suited to the material is then required.

The T3973 160 product specification (Carl Kammerling, 6 November 2024) states a 9 mm maximum cable diameter for suitable copper and aluminium wires. This is not a 9 mm² cross-section or a rating for other metals. My test on a bundle of 2.5 mm² copper conductors is a separate field observation. The current T3973A 160 range must be checked against its own model code.

An armored cable or a metal structure cannot be cut with a connection tool, whatever its size. Those cuts require a cutter dedicated to the metal concerned.

Cutting a series of conductors: the order I follow

When a box has several wires waiting to be prepared, I cut everything before connecting anything. Picking the cutter back up in the middle of the tightening phase makes me lose the thread of the work.

I identify each conductor before the cut, then I cut them in the hollow of the blades, keeping the same slack on each one. The amount of slack is decided at that moment.

Then comes the check, wire after wire: a crushed section is redone right away, whereas once the terminal is tightened, everything has to be taken apart again to get back to it.

On a harness already in place in a cable duct, I cut one conductor at a time, leaving the others aside. This avoids pulling on the neighboring connections.

The blade profile is also used for stripping, but I do not mix the two actions. On a connecting conductor, the jaw can remove the sheath; on a thin wire, I prefer the notch on the multifunction pliers.

After stripping, I check for a clean insulation edge and copper without nicks, gouges or missing strands. Shine alone does not tell me whether the blade damaged the conductor; I inspect the metal itself.

The pliers cut, but do not mark: it is the marking applied before the cut that keeps the harness readable in a box.

Multifunction pliers T3910-210: stripping, gripping and LOOP eyelet

The T3910-210 is the pliers I take out most often. With its 210 mm and its massive forged head, it brings together, on a single tool, the operations that come before the connection.

It is heavy in the hand: that is the price of the all-in-one. In exchange, it saves carrying three different pliers on the belt for a job on a ladder.

The head groups together three work zones: a tapered and grooved gripping nose, a series of stripping notches, and a shear-cutting zone.

The grooved nose grabs a conductor at the bottom of a box and straightens a twisted core. The cutting zone cuts stranded wire as well as solid wire. Stripping has its own notches, separated by conductor family.

The tip gets used more often than you would think. In a flush-mounted box, a conductor that has slipped behind the others can be retrieved with the point, without taking the rest apart.

The serrations grip copper as well as insulation. I also use them to gently pull a waiting wire, staying on axis, without bowing the conductor.

To straighten a twisted core before presenting it to a terminal, a few passes between the jaws are enough. I then check that the strand has not been flattened.

Stripping flexible and rigid wire without nicking the copper

The stripping station carries a double engraved marking: one series of notches for flexible conductors, another for rigid ones. The bores are distinct, and the mark is read before closing the pliers.

Each notch corresponds to an insulation and core diameter: stripping is done with a firm motion, without biting into the metal. The motion stays the same every time: choose the gauge, close without yanking, then check the copper.

On a copper conductor of 1.5 mm², the stripping stayed clean: no trace of a nick on the metal, no cut strand. That’s what to watch with any wire stripper, because a nicked core weakens the conductor without it showing at first glance.

To situate this station against dedicated strippers, my ranking of the best wire strippers details the other approaches.

The LOOP eyelet for screw terminals and pulling needles

One detail I use all the time on this stripper: the through-hole machined into the jaw, identified by the LOOP marking.

It’s used to form the eyelet of a solid conductor of 1.5 or 2.5 mm²: you insert the core into the hole, rotate the stripper, and the wire takes a regular circular curve, with no abrupt kink.

This loop is screwed onto the screw terminals of older devices. On more recent jobsites, it’s mainly used to make the attachment ring of a wire-pulling needle.

This is the typical case of re-pulling conductors through an already-cast ICTA conduit: a compact and solid eyelet holds up better than an improvised twist when the bundle snags in the conduit.

1 Loop-forming hole Loop-forming hole

LOOP bending eyelet

The through hole forms clean eyelets for pulling conductors.

Sparx Elec

Preparing an end-to-end connection

Before opening the stripper, I look at what the terminal block expects: a straight conductor on an automatic-clamp terminal block, an eyelet on a screw terminal.

Then comes the cut, then the stripping in the matching notch. I choose the gauge by reading the engraving on the jaw, never by judging the wire by eye.

The check comes before tightening: I inspect the core over the whole stripped length and check that no filament comes away when I twist the strand slightly.

When the connection calls for an eyelet, I form it before presenting the conductor in the terminal. Once the wire is engaged, the loop is hard to put right.

The value of the multifunction tool lies in that sequence: cutting, stripping and looping without setting the tool down between movements.

Shock resistance after a strike test

To put the structure to the test, I subjected the T3910-210 to a continuous mechanical strike test. For more than five minutes, the back of the forged head was used to drive in PVC trunking covers and stubborn metal anchor tabs.

Result: no axial play at the pivot rivet, cutting edges still flush, with no abnormal friction on opening.

The forged steel absorbs the shock wave. The caveat lies in the assembly itself: a riveted joint is not designed for that use.

VDE insulation on both pliers: what the marking guarantees

Both pliers are advertised as VDE: each tool is individually tested at 10 000 V at the factory, for live working up to 1 000 V. That is the principle of the EN 60900 standard, which governs insulated hand tools.

The cable cutter datasheet also lists compliance with VDE 0682/201 and ISO 5749. For the details of what the standard requires from an insulated tool, I refer to my article on 1 000 V insulated tools.

The marking guarantees that the handle and the insulation withstand the dielectric test, not the absence of risk during the job.

An insulated tool limits contact with a bare live part; it does not remove the need for suitable PPE, such as insulated gloves for live working, or for preparing the job.

A check before each use is part of the routine: handles and insulation intact, anti-slip guards in place, no deep marks on the handle. Breached insulation cannot be compensated for — the tool leaves the tool bag.

• Individual 10 000 V test before leaving the factory, for a stated use below 1 000 V
• EN 60900 compliance claimed on both references
• Dual-material handles and anti-slip guards on the cable cutter
• Simple visual check before each job

The three markers to remember on the tool itself: the VDE marking, the reference of the pliers, and the condition of the insulation under the handles. That is what you check in two seconds when you take the pliers out of the tool bag.

The check before it comes out, in order

I start with the insulation, under the handles and up to the guards. A handle that is marked or peeling stops the tool from coming out, no discussion.

Next I move on to the joint: I open and close the pliers twice. A hard spot or abnormal play can be felt immediately by hand.

I finish with the cutting edges and the condition of the head. A pair of pliers that has taken a knock is set down on the workbench: I examine it before putting it back in the tool bag, never after.

This check takes only a few seconds and is done on every outing, not once a month.

Care and wear: keeping insulated pliers reliable

Insulated pliers do not require heavy maintenance, but they require consistency. After a day in drilling dust, I wipe them dry before putting them away.

Storage matters as much as cleaning. Every pair of pliers has its place in the tool bag: a tool that rattles around at the bottom of the bag takes knocks on the insulation as much as on the cutting edges.

The first thing I watch is play at the joint. A pivot that has developed play can be felt when opening: the jaw floats instead of guiding the wire.

The cutting edges come next. I run my fingernail along the edge of the blade to feel for any burr: a marked blade cuts less cleanly and takes more effort.

On the insulation, I look at the handles in the light, not absent-mindedly. A deep mark or a handle coming away and the tool leaves the tool bag.

What I avoid: leaving them to sit in a damp vehicle, or behind a window in full sun. That is not where I store a tool that has to stay reliable when live.

Pliers that have fallen from a ladder go through the full check before being used again. That is the point on which I do not cut corners.

The rest is a matter of rotation: pliers used every day wear at the pivot long before the insulation moves. The regular action itself does not change.

Cutting 16 mm²: a separate job

On 3 October 2026, I cut a 16 mm² copper conductor without difficulty using a RedLine VDE CombiCutter3 Max. A smaller cutting plier also went through 16 mm² that day, though I did not note its reference.

Both cuts were separate from the T3973-160 test on a 2.5 mm² bundle. Neither one sets the manufacturer’s maximum capacity for the model concerned.

T3973-160 or T3910-210: how to choose

Which one to choose is decided based on the jobs you carry out, not on the product sheets. Four questions are enough to settle it.

On price, the manufacturer does not publish a recommended retail price for these two references: the price has to be requested from a distributor.

The two pliers do not replace each other depending on format either. The T3910-210 covers preparation at 210 mm, the T3973-160 slips in everywhere at 160 mm: the two coexist without duplication on the tool belt.

To crimp ferrules onto flexible conductors, that is another tool: the crimping pliers have their own jaws and cannot be improvised with multifunction pliers.

Common mistakes when stripping and cutting

The most common mistake lies in the notch. You pick the gauge by eye, you close the pliers, and the insulation comes away with a piece of the core. The engraved mark is there to be read before squeezing.

The second is the weak motion. A strip redone three times in the same notch marks the copper as much as a wrong gauge.

Third mistake: yanking the insulation off by pulling on the conductor. A short twist of the pliers is enough; the sheath comes away effortlessly on the strand.

On the cut, the classic mistake is to squeeze in jerks. Shearing calls for a firm, continuous motion, otherwise the blade slips instead of cutting.

There is also the temptation to cut several conductors in a single motion. The bundle shears cleanly, but I lose count of the markers put on earlier.

Finally, the storage mistake: picking up pliers lying at the bottom of a box without looking at the insulation. It is the fastest check and the one most often skipped.

On-site use cases: where these two pliers prove useful

On a distribution board, the multifunction pliers do all the preparation: I cut to the length of the trunking, I strip, I form the loop when the terminal calls for it.

In a flush-mounted box, the cable cutter’s format has the advantage. Space is scarce, and long pliers open their handles poorly against the masonry.

At the end of a pull, when the conductors arrive too long in an enclosure, the cable cutter trims them back as close as possible without damaging the neighboring wires.

At height, on a luminaire to prepare, the multi-tool saves carrying several tools up on the belt: I come back down with the pliers that did the cutting.

On old wiring devices with screw terminals, the eyelet formed with the pliers gives a clean connection. I prefer it to a wire simply stripped and tightened under the screw.

On an installation rework, I often take both: the multi-tool prepares the panel conductors, the cable cutter adjusts those that arrive too long.

What I don’t ask of them, however: crimping a ferrule, cutting steel or armored cable, acting as a lever to force a nut. Those actions call for another tool.

And I never consider the insulation a green light. It protects the action, it replaces neither the preparation of the job nor PPE.

What I take away from practical use

In my use, two findings stand out: the shear cutting does exactly what it promises, and the multi-tool brings together actions that would otherwise require three tools.

• Clean cut without crushing: a bundle of 5 to 6 copper conductors of 2.5 mm² cut through without deforming the sheaths
• Clean stripping with the separate flexible and rigid notches, copper intact afterwards
• Consistent LOOP eyelet for screw terminals and wire-pulling needle rings
• VDE 1 000 V insulation individually tested at 10 000 V, on both models
• Two complementary formats: 160 mm compact for trimming, 210 mm for preparing

• The T3973-160 is specified for copper and aluminium only: it is a plier for connecting conductors
• The T3910-210 is a 210 mm format: the massive head costs you in weight and bulk in very tight spaces
• The hammering test was not a dielectric safety retest: the T3910-210 should not be used for live work after this misuse without manufacturer confirmation of its condition

How the sharpening and the pivot hold up over time will be judged in use; nothing moved during the test. The rest comes down to how consistently the tool is checked before use: an insulated plier remains a safety tool, not a consumable.

Article: https://www.sparx-elec.com/gb/ck-tools-redline-vde-pliers-review/
Edition: GB — English
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