Will 1/8 inch heat shrink fit over a crimp connector?

Not over the connector barrel. An insulated butt splice on 18–16 AWG measures 5–6mm across, while 1/8" tubing has a 3.2mm expanded bore. Step up to 1/4" for the splice. Use 1/8" for the conductor run, for re-jacketing a nicked section, or for band-marking a harness.

Is 1/8 inch dual wall heat shrink waterproof?

Yes. The adhesive inner wall melts at 120°C and seals the tubing to the wire insulation, stopping moisture from wicking down the strands. That is the practical difference between dual-wall and ordinary single-wall tubing on a trailer or engine bay harness.

How many connections does a 1/8 inch short roll cover?

A 10ft roll cuts into roughly 40 pieces at 3 inches each — comfortably enough to rebuild a trailer harness or an appliance loom with tubing left over. The short pack exists so you are not buying 120 feet of a size you need in short lengths.

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.

Is 1/8" dual wall rated for a 1000 Vdc PV repair?

Yes — as a seal, not as insulation. This 1/8" (3.2mm) tubing is rated 600 V rms, and we hold no rating above it, so it is not the insulation of record on a 1000 Vdc string: the conductor carries that rating, UL 4703 PV wire or RHW-2/USE-2, both rated 2000V. The 10ft pack is sized for a handful of 16–18 AWG joints on a service call, and the voltage class is identical to the large rolls. If a supplier offers you 1000V rated tubing, ask which standard, edition and file number backs the number.

3:1 · 1/8" · 10 ft● LIVE SPEC

10ft Short PackAdhesive Liner600V Rated HELIXAL 3:1 Dual Wall Heat Shrink Tubing 1/8" (3.2mm) — 10ft Short Pack

BLACK · 1/8" · 10 FTHELIXAL · ISO 9001

3:1 Dual Wall · 10ft Short Pack

1/8"
3:1 Heat Shrink

Q: What size wire does 1/8 inch heat shrink fit?

Helixal 1/8" (3.2mm) 3:1 short roll heat shrink fits bare 16–18 AWG wire — trailer lighting, appliance leads, speaker runs, and 12V accessory circuits. ABYC E-11 Table XI rates 18 AWG at 7A and 16 AWG at 10A bundled. It recovers to about 1.1mm, gripping the insulation without necking it.

Fits16–18 AWG3.2mm

1/8 inch heat shrink tubing fits 16–18 AWG wire — the gauge that carries most trailer lighting, appliance leads, speaker runs, and 12V accessory circuits. ABYC E-11 Table XI rates 18 AWG at 7A and 16 AWG at 10A in a bundled chassis run. At 3.2mm expanded, the tube slides freely over bare 16 and 18 AWG conductors and recovers to about 1.1mm, gripping the insulation without necking it. Remember the wire is not the widest thing you are covering: an insulated butt splice on 18–16 AWG measures 5–6mm across the barrel, which calls for 1/4 inch rather than 1/8 inch. Use this size on the conductor itself, to re-jacket a nicked section, and to band-mark a harness. The adhesive inner wall melts at 120°C and stops moisture wicking down the strands. A 10ft pack rebuilds a trailer harness with tubing to spare.

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Size1/8" · 3.2mm

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 · 10 ft per roll

$7.9910 ft spool

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SKU: B0FJMXCDGC · 1/8" (3.2mm) · 10 ft

Spec Sheet

1/8"
data sheet.

Full industrial dual-wall adhesive spec in a convenient 10ft pack. Same 600V rated, waterproof polyolefin construction as the large bulk rolls.

Imperial Size

1/8"

Expanded diameter

Metric Size

3.2mm

Nominal

Roll Length

10 ft

Per spool

Wire Gauge

16–18 AWG

Bare conductor

Shrink Ratio

3:1

Dual wall

Construction

Dual Wall

Adhesive inner liner

Inner Layer

Hot Melt Adhesive

Waterproof seal

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

Adhesive Flow

120°C (248°F)

Keep heating until it shows

Material

Polyolefin

Outer sleeve

Flammability

Self-extinguishing

UL 224 Recognized

Color

Black

Standard finish

Standards

UL 224 Recognized

UL file E361230 · RoHS

UV Resistance

Yes

Outdoor safe

Waterproof

Yes — adhesive seal

360° coverage

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.

★★★★★

Better than electrical tape by far!

Used this on vehicles (starters) and trailer lights. Easy to use, looks like a professional fitting, and seems to hold tight.

Verified Buyer · Verified Purchase★ Verified

★★★★★

Good quality and sealing heat shrink

Heat shrink works good. Makes a nice sealed wire connection. Better than pre-cut heat shrink — you can make whatever length you want.

R Davis · Verified Purchase★ Verified

★★★★★

Smart format for repair work

Great for keeping several sizes on hand without the bulk. Same quality as the large rolls — the adhesive seals perfectly every time.

Travis M. · Verified Purchase★ Verified

Customer Reviews

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Sizing & Application — 1/8 inch, 10ft pack

One pack, one trailer harness, itemised.

1/8 inch (3.2mm) fits bare 16–18 AWG — trailer lighting, appliance leads, speaker runs, 12V accessory circuits. ABYC E-11 Table XI rates 18 AWG at 7A and 16 AWG at 10A bundled. The most common single job at this size is a trailer harness rebuild, and it is worth setting out exactly what that consumes, because the answer determines whether ten feet is enough.

What a harness rebuild actually uses at this diameter

A standard four-way trailer harness has four circuits — tail, left stop and turn, right stop and turn, ground. Each one gets a connection at the plug end, a connection at the light, and usually one break-out along the run. That is roughly twelve joints, at 3 inches of tubing each, or about three feet.

Add identification bands at each break-out and at the plug, another 15–25mm apiece, and a re-jacketed section or two where the old loom has chafed against the frame. Call it four to five feet for the whole rebuild. A ten-foot pack does the harness and leaves enough for the next one, which is the point.

What it will not do is the splices. A crimped butt splice on 18–16 AWG measures 5–6mm across the barrel and needs the 1/4 inch pack. Anyone rebuilding a harness properly holds both sizes, and the two packs together still cost less than a single bulk roll of either.

1/8 inch short pack at a glance

Property	Figure	Why it matters
Expanded diameter	3.2mm (1/8")	Slides over bare 16 and 18 AWG freely
Recovered diameter	≈1.1mm	Grips the insulation without necking it
Bare wire range	16–18 AWG	7A for 18 AWG, 10A for 16 AWG bundled (ABYC E-11 Table XI)
Four-way harness rebuild	≈4–5 ft	Twelve joints at 3 in, plus bands and re-jacketing
Pack yield	≈40 pieces at 3 in	Two full harnesses per pack
Bulk equivalent	60 ft roll	Twelve harnesses — workshop stock rather than job stock

Thread tubing onto the wire before crimping or soldering. Threading afterwards means cutting the joint you just made.

What this pack will not cover

01 · The butt splices

An insulated splice barrel on 18–16 AWG runs 5–6mm, past a 3.2mm bore. Buy the 1/4 inch pack alongside this one — that pairing is how the job actually gets done.

02 · A workshop doing this weekly

At a harness a week the 60ft roll is the right economics. The pack is sized for the owner or the occasional job, not for a production bench.

03 · Dry indoor identification only

If the tubing is going inside a cabin or a panel purely to band-mark, the 1/8" 2:1 does that and slits off cleanly when a circuit changes.

04 · Above 600V

Rated 600V rms. On a 1000V run the conductor carries its own insulation rating and heat shrink acts as a seal over it.

Keep reading →1/4" 3:1 Dual Wall — 10ft pack for the splices · Automotive Wire Protection Guide · 1/8" 3:1 Dual Wall — 60ft bulk roll

How it shrinks.

Measure & Select

Verify the expanded diameter is 20–30% larger than your wire or connector. The tubing must slide freely before heat is applied — if it drags, go one size up.

Cut & Thread

Cut to length and thread onto the wire or cable before making the splice or crimp. Overlap each terminal or connector end by at least 10mm for a proper seal.

Apply Heat

The tubing starts shrinking at 100°C, but the adhesive liner only flows at 120°C — so keep the heat gun moving past the point where it looks shrunk. Start at the center and work outward to push air toward the ends. Adhesive will appear at the tube ends — that is your visual seal indicator.

Inspect

The tubing should be tight and uniform with adhesive visible at both ends. No gaps, lifting, or cold spots. Pull-test the finished connection to confirm the adhesive bond.

✓

Watch

See 1/8" In Use

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Size Reference

Expanded vs.
recovered.

Actual 1/8" tube at full expanded diameter (3.2mm) and after heat recovery. Use this as your fit reference before cutting.

Expanded: 3.2mm — slides over 16–18 AWG

Shrink ratio: 3:1 on full heat

1/8" 3:1 heat shrink tubing — expanded diameter 3.2mm versus recovered size reference diagram

1/8" · 3.2mm expanded3:1 recovery · fits 16–18 AWG

Use it on.

Try Before You Buy Bulk

Order a 10ft pack to verify the size fits your connector before committing to a large roll. Test fit, shrink one piece, then buy the bulk roll with confidence.

Field Repair Kits

Keep a set of short rolls on the service van or boat. Enough for any repair job without hauling large rolls — one 10ft roll handles most splices.

Stock Multiple Sizes Cheap

For the same cost as one large roll, stock several different sizes in short packs. Covers more connector diameters for the same investment.

Marine & Outdoor Spot Repairs

Seals individual connections on boat wiring, outdoor electrical, and trailer harnesses. Same waterproof adhesive seal as the large rolls — just 10ft.

Low-Volume Production

Ideal for small-batch cable assembly and prototype builds where a full bulk roll would sit unused. Cost-effective for runs of fewer than 50 connections.

One-Off Automotive Builds

Custom automotive and motorcycle builds often need several sizes in small quantities. Short rolls let you match every connection without leftover material.

Size Guide

1/8" Questions.

Technical Guides

From the Blog

All Guides →

Free Tool

1/8" 3:1 Large Roll →Bulk 20–60ft roll

All 13 sizes.

View line overview →

3/32"2.4mm10 ft

Current1/8"3.2mm10 ft

3/16"4.8mm10 ft 1/4"6.4mm10 ft 5/16"8mm10 ft 3/8"9.5mm10 ft 1/2"12.7mm10 ft 5/8"16mm10 ft 3/4"19.1mm10 ft 1"25.4mm10 ft 1-1/4"31mm10 ft 1-1/2"38mm10 ft 2"50.8mm10 ft

Recovered diameter is approx. 1/3 of the expanded size shown · All sizes ship to USA & Canada

1/8"
3:1 Heat Shrink

1/8"
data sheet.

What the
trade says.

One pack, one trailer harness, itemised.