How to Choose a Wire Stripper Notch for Stranded Conductors

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Choosing a wire stripper notch for stranded conductors is not as simple as matching the number printed on the insulation. A 14 AWG stranded wire and a 14 AWG solid wire have the same copper cross-sectional area, but their outside diameters, insulation types and stripping behavior can differ. The right notch should cut the insulation cleanly without flattening strands or scoring copper.

Read the wire marking first

Find the conductor size on the cable jacket, spool label or wire printing. Common sizes include 18, 16, 14 and 12 AWG. The AWG number describes the copper conductor, not the total outside diameter of the insulated wire.

For example, 14 AWG copper is approximately 2.08 mm² in cross-sectional area. The insulation may add several millimeters to the cable diameter, especially on automotive, appliance and industrial wire. Do not select a stripper notch by measuring the insulated wire with calipers; that measurement includes insulation and will lead you to a notch that is much too large.

Also check whether the wire is actually stranded. Fine-strand welding cable, silicone test lead wire and flexible hookup wire can have substantially different outside diameters from ordinary building wire, even when all are marked 12 AWG. The conductor size is the starting point, but the stripper’s notch must suit the insulation and strand construction.

Why stranded wire needs care

A stranded conductor is made from multiple small wires twisted together. If the stripper notch is too small, its cutting edges can bite into the outer strands. The damage may be hard to see, but it reduces the effective conductor area and creates a weak point that can break when the wire is bent.

If the notch is too large, it may fail to cut through the insulation cleanly. You will then have to pull harder, rotate the tool or make a second cut. That can stretch the insulation, scatter strands or leave a ragged end. With soft PVC insulation, a slightly oversized notch may work. With tough nylon, cross-linked polyethylene or rubber insulation, it often will not.

For a first cut, close the stripper only until the insulation is scored. Pull the insulation off rather than twisting the tool aggressively. Inspect the exposed copper under good light. If even one strand is cut, move up to the next larger notch or use a stripper designed for fine-strand wire.

Match the notch to conductor size

Use the stranded-wire marking on the tool when it is provided. Some strippers print separate ranges for solid and stranded wire; others use one set of holes for both. A notch marked “14 AWG stranded” is the best first choice for ordinary 14 AWG flexible wire.

When a wire falls between two marked notches, test the larger notch first. A larger notch is less likely to cut copper, but it may not remove the insulation in one pull. Make a shallow score, then remove the insulation by hand. If the insulation remains attached around most of the circumference, try the smaller notch carefully on a scrap end.

Choose the stripper style

For occasional electrical work, a conventional manual wire stripper for stranded wire is usually the best value. These tools are inexpensive, durable and easy to inspect. They work particularly well on common PVC-insulated 12–18 AWG wire when the notch markings are clear.

A precision stripper is better for small conductors such as 20–26 AWG. Its narrow notches and sharper cutting edges reduce the force needed to remove insulation. It is worth buying when you regularly work on control wiring, electronics or automotive circuits. The trade-off is that the blades are less tolerant of misuse and can be damaged by cutting cable, steel-reinforced wire or oversized conductors.

Self-adjusting strippers are convenient when you work with several wire sizes in succession. They generally clamp the insulation and set the cutting depth automatically. However, cheap versions can crush soft stranded wire, leave a partial cut or pull insulation off unevenly. A quality self-adjusting wire stripper makes sense for repetitive work, not necessarily for a few household repairs.

For fine-strand cable, look for a tool explicitly described as suitable for fine-strand, flexible or welding cable. Do not assume that an expensive automatic stripper will handle it correctly. Some mechanisms are designed around ordinary conductor diameters and can pull loose strands from very flexible cable.

Test the notch before using it

Cut off a 50–75 mm scrap and test the selected notch. Place the wire squarely in the notch, close the handles with moderate pressure and pull the insulation away in one smooth motion. The cut should be circumferential, and the copper should remain round and bright.

Look for several failure signs: a missing outer strand, a flattened conductor, insulation that stretches instead of separating, or a deep ring pressed into the copper. A shallow mark in the insulation is normal. A visible groove in the metal is not. If the tool leaves a groove, discard that stripped end and adjust the notch or cutting pressure.

Features worth paying for

Clear, permanently marked AWG sizes matter more than a large number of extra functions. Serrated jaws for crimping terminals are useful, but they do not make a stripper better. A spring return reduces hand fatigue, and narrow jaws improve access inside crowded boxes.

For frequent work, consider a professional AWG wire stripper with hardened, replaceable blades or a calibrated adjustment. For occasional 12–18 AWG wiring, the cheaper manual tool is fine if its notches are accurate and its cutting edges meet cleanly. Spend more when you need repeatable results, very small wire sizes or difficult insulation—not simply because the handles look more substantial.