What wire does 3/32 inch heat shrink tubing fit?

Helixal 3/32" 2:1 has a 2.4mm expanded bore and recovers to roughly 1.2mm, which suits bare 20–22 AWG conductors — thermocouple leads, LED strip runs, PCB hook-up wire, and instrument sensor cable. NFPA 70 Table 310.15 rates 22 AWG at 3A and 20 AWG at 5A, so at this gauge the joint fails from a bad seal or a broken strand long before it fails from current.

Is 3/32 inch too small for a butt splice?

Almost always, yes. A crimped 22–18 AWG insulated butt splice measures 5–6mm across the barrel and needs 1/4 inch tubing. Use 3/32 inch on the bare conductor either side of the splice, not over the barrel. Sizing to the copper instead of to the widest point it must pass over is the single most common heat shrink mistake at this gauge.

How much does 3/32 inch heat shrink shrink down to?

The 2:1 ratio halves the diameter: 2.4mm expanded recovers to approximately 1.2mm at full heat. Choose the size so the 2.4mm bore slides on freely before heating and the recovered 1.2mm still grips the conductor — if the tube is loose after shrinking, it was a size too large to begin with.

Is 3/32 inch 2:1 heat shrink waterproof?

No. This is single-wall polyolefin with no adhesive liner — moisture-resistant, but water will wick along the strands underneath it. For a sealed joint at this gauge, use the Helixal 3/32" 3:1 Dual Wall, whose hot-melt liner flows at 120°C and blocks that capillary path.

How far does a 120ft roll of 3/32 inch go?

Each roll holds 120 feet — the longest bulk length we stock in this size. At the 1–2 inch pieces typical of fine-gauge work, one roll covers several hundred terminations, which is why this size is normally bought once a year rather than per job.

Is the 600V rating AC or DC?

AC. Heat shrink tubing is rated under UL 224, which expresses voltage in volts rms — so our 600V tubing is rated 600 V rms, and we hold no rating above it. The UL 224 standard ratings are 150V, 300V and 600V; since Edition 8, published February 2026, an optional higher voltage rating is also available, which our tubing does not carry. On any circuit above 600V — a 1000 Vdc solar string, for example — the conductor itself must carry the insulation rating, UL 4703 PV wire or RHW-2/USE-2, both rated 2000V, with heat shrink used as a sealing cover over those already-rated components rather than as the primary insulation.

Can I use 3/32" 2:1 heat shrink on a 1000V solar array?

As a cover, not as insulation — and for an outdoor PV termination the 3:1 dual wall is the better choice, because it seals. This 3/32" (2.4mm) tubing is rated 600 V rms and we hold no rating above it, so on a 1000 Vdc string the conductor carries the rating: UL 4703 PV wire or RHW-2/USE-2, both rated 2000V. Where this size earns its place is re-jacketing and band-marking 20–22 AWG runs. If a supplier offers you 1000V rated tubing, ask which standard, edition and file number backs the number.

2:1 · 3/32" · 120 ft● LIVE SPEC

UL 224 RecognizedFlame Retardant600V Rated HELIXAL 2:1 Standard Heat Shrink Tubing 3/32" (2.4mm) — 120ft Roll

BLACK · 3/32" · 120 FTHELIXAL · ISO 9001

2:1 Single Wall · UL 224 Recognized

3/32"
2:1 Heat Shrink

Fits20–22 AWG2.4mm

3/32 inch heat shrink tubing fits 20–22 AWG wire — the gauge used for thermocouple extension leads, PCB hook-up wire, LED strip wiring, and e-bike controller signal cables. NFPA 70 Table 310.15 rates 22 AWG at 3A and 20 AWG at 5A; at these current levels, insulation quality and environmental resistance matter more than conductor sizing. At 2.4mm expanded diameter, this tube slides freely over 20 and 22 AWG conductors and recovers to approximately 1.2mm — a firm grip on fine wire insulation without crushing it. The single-wall 2:1 construction, qualified to UL 224, is the correct specification for dry indoor applications: band marking wire bundles, insulating solder joints on PCBs, and organizing control-panel conductors in protected enclosures. When wiring will be exposed to moisture, condensation, or outdoor humidity, step up to the 3:1 dual-wall adhesive-lined version for a hermetic seal. At 120 feet per roll, electronics production shops and panel builders cover this fine-gauge size at one of the lowest per-foot costs available for 20–22 AWG, eliminating repetitive mid-project re-orders.

★★★★★4.7 · 225 verified ratings across the Helixal range

26 in stock · Ships in 24h

Order up to 26 online · need more? Trade pricing

Size3/32" · 2.4mm

3/32"1/8"3/16"1/4"5/16"3/8"1/2"5/8"3/4"1"1-1/4"1-1/2"2"

Click any size to navigate · 120 ft per roll

$14.99120 ft spool

→ Dispatched within 24 hours — delivered in 1–3 days→ 30-day money-back guarantee — 30 days to return it

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SKU: B0FJHK3M9X · 3/32" (2.4mm) · 120 ft

Spec Sheet

3/32"
data sheet.

High-volume UL 224 Recognized polyolefin at an honest per-foot cost. The industry standard for band marking, bundling, and dry indoor electrical insulation.

Imperial Size

3/32"

Expanded diameter

Metric Size

2.4mm

Nominal

Roll Length

120 ft

Per spool

Wire Gauge

20–22 AWG

Bare conductor

Shrink Ratio

2:1

Single wall

Construction

Single Wall

No adhesive liner

Adhesive Liner

None

Not waterproof

Voltage Rating

600V AC

UL 224 — 600 V rms

Temp Rating

-55°C to +125°C

Continuous service

Shrink Temp

100°C (212°F)

Shrinking starts

Material

Polyolefin

UL 224 Recognized

Certification

UL 224

Recognized Component

Flammability

Self-extinguishing

UL 224 Recognized

Color

Black

Standard finish

Moisture

Resistant — not sealed

Single wall only

Sizing over a connector? The Wire Gauge row above is for bare conductor. Heat shrink must be sized to the widest point it passes over, so a crimped butt splice or lug barrel needs a larger tube than the wire alone — a 22–18 AWG splice barrel measures 5–6mm, a 16–14 AWG barrel 7–8mm, and a 12–10 AWG barrel 9–11mm. Measure the barrel, allow about 20% clearance, and confirm the recovered diameter is smaller than the narrowest thing the tube must grip. Use the size calculator.

What the
trade says.

Verified Buyers ★ · Full Range4.7★★★★★225 ratings · 84% 5-starCombined verified-buyer rating for every Helixal product — all ratios, all sizes — not this size alone.

★★★★★

Nice product at great price

Was wiring my car and had quite a few smaller wires to crimp and cover. This worked great — shrinks clean and consistent every time.

Church's · Verified Purchase★ Verified

★★★★★

Perfect for bulk workshop use

Bought this for my automotive workshop and the 120ft roll is exactly what I needed. Shrinks consistently and cleanly every time. Much better value than small packs.

Mike R. · Verified Purchase★ Verified

★★★★★

Professional finish every time

Clean black finish, no bubbles or wrinkles when applied correctly. UL listing is important for commercial electrical work — ticks that box too.

James T. · Verified Purchase★ Verified

Customer Reviews

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Sizing & Application — 3/32 inch

On a solder joint the tube is not insulation. It is strain relief.

3/32 inch (2.4mm) recovers to roughly 1.2mm, which suits bare 20–22 AWG — thermocouple leads, PCB hook-up wire, LED strip runs, instrument sensor cable. NFPA 70 Table 310.15 rates 22 AWG at 3A and 20 AWG at 5A, so nothing at this gauge fails from current. It fails mechanically, at the one place a soldered joint always fails, and that is the job a single-wall tube does properly.

Why soldered fine wire breaks just past the joint

Solder wicks up the strands by capillary action, typically two or three millimetres past the joint itself. Over that length the conductor stops being a flexible bundle of filaments and becomes a single rigid rod. The transition from rigid to flexible is abrupt, and every vibration or handling cycle concentrates at that boundary.

Copper work-hardens as it flexes. The break, when it comes, is almost never at the solder — it is a few millimetres up the wire, inside insulation that looks untouched. Anyone who has repaired the same headset cable or sensor lead twice has seen this: the second failure appears next to the first repair rather than at it.

A tube spanning the joint moves that boundary. It distributes bending over its own length instead of letting it concentrate at one point, which is why the tube should extend well past the wicked solder onto plain wire — 10mm either side is a reasonable habit at this gauge. That is a mechanical function, and single-wall polyolefin performs it without paying for an adhesive liner the joint does not need.

3/32 inch at a glance

Property	Figure	Why it matters
Expanded diameter	2.4mm (3/32")	Slides over bare 20 and 22 AWG cold
Recovered diameter	≈1.2mm	The 2:1 ratio halves; check it still grips your insulation
Bare wire range	20–22 AWG	3A for 22 AWG, 5A for 20 AWG (NFPA 70 Table 310.15)
Overlap to aim for	≈10mm each side of the joint	Spreads bending past the solder-stiffened section
Wall type	Single-wall polyolefin	Insulates, protects and relieves strain; does not seal
Roll length	120 ft	Several hundred pieces at the 1–2 in lengths this gauge uses

Fine tubing reaches recovery temperature fast. Keep the gun moving and work from a greater distance than you would on a 1/2 inch tube.

When 3/32 inch 2:1 is the wrong choice

01 · The joint gets damp

Single-wall tubing is moisture-resistant, not waterproof, and at this gauge water wicks between the strands under the tube. For instrument and sensor wiring exposed to condensation, use the 3/32" 3:1 Dual Wall, whose hot-melt liner closes that path.

02 · There is a crimp barrel

A 22–18 AWG insulated butt splice measures 5–6mm across and will not enter a 2.4mm bore. The splice needs 1/4 inch; 3/32 inch is for the conductor either side.

03 · The wire is 16 AWG or heavier

This size covers 20 and 22 AWG only. Move to 1/8 inch at 16–18 AWG rather than stretching a tube on cold — a pre-stretched tube recovers unevenly.

04 · Above 600V

Our rating is 600V rms. On a 1000 Vdc array an inspector looks at the conductor, not the tubing — the wire carries the insulation rating and heat shrink covers and seals the termination, never the circuit voltage.

Keep reading →3/32" 3:1 Dual Wall — the sealed version · Solder and Heat Shrink · Dual Wall vs Single Wall Heat Shrink

How it shrinks.

Measure & Select

Choose a size where the expanded diameter is 20–30% larger than your wire or bundle. Smaller tubes will slide on easier; slightly oversize is better than too tight.

Cut & Thread

Cut to length and thread onto the wire before making the splice. The tubing cannot pass over a crimped terminal — position it first, then complete the connection.

Apply Heat

The tubing starts shrinking at 100°C — use a heat gun and keep it moving until it has shrunk evenly along its length. Work from the center outward. Avoid open flame — it scorches the tubing and creates uneven shrink.

Inspect

Finished tubing should be tight with no bubbles or lifted edges. No adhesive will appear at the ends — this is single-wall tubing. Confirm even recovery across the full length.

✓

Watch

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Size Reference

Expanded vs.
recovered.

Actual 3/32" tube at full expanded diameter (2.4mm) and after heat recovery. Use this as your fit reference before cutting.

Expanded: 2.4mm — slides over 20–22 AWG

Shrink ratio: 2:1 on full heat

3/32" 2:1 heat shrink tubing — expanded diameter 2.4mm versus recovered size reference diagram

3/32" · 2.4mm expanded2:1 recovery · fits 20–22 AWG

Use it on.

Wire Band Marking

Band-marks conductors in control panels, distribution boards, and wiring harnesses where identification is critical and moisture is not a concern.

Electronics Repair

Insulates component leads, solder joints, and board-level wiring. Single-wall provides a clean, thin sleeve without added adhesive bulk.

Hobbyist & Maker Builds

Ideal for 3D printer wiring, robotics, LED builds, and RC applications where large roll volumes keep per-foot cost low.

Appliance Wiring Repair

Covers spliced leads and repaired harnesses on household appliances in dry indoor environments. UL 224 Recognized material meets installation codes.

Soldering Strain Relief

Provides mechanical strain relief over solder joints on wire-to-wire and wire-to-component connections in benchtop and production builds.

Control Panel Conductors

Organizes and insulates signal wiring, thermocouple leads, and I/O conductors inside dry rated electrical enclosures and panels.

Size Guide

3/32" Questions.

Technical Guides

From the Blog

All Guides →

Free Tool

3/32" 3:1 Dual Wall →Waterproof adhesive-lined 3/32" 3:1 Short Pack →10ft trial/repair pack

All 13 sizes.

View line overview →

Current3/32"2.4mm120 ft

1/8"3.2mm120 ft 3/16"4.8mm120 ft 1/4"6.4mm120 ft 5/16"8mm120 ft 3/8"9.5mm120 ft 1/2"12.7mm120 ft 5/8"16mm90 ft 3/4"19.1mm90 ft 1"25.4mm90 ft 1-1/4"31mm60 ft 1-1/2"38mm60 ft 2"50.8mm60 ft

Recovered diameter is approx. 1/2 of the expanded size shown · All sizes ship to USA & Canada

3/32"
2:1 Heat Shrink

3/32"
data sheet.

What the
trade says.

On a solder joint the tube is not insulation. It is strain relief.