Will 1/2 inch fit over a lug crimped on 2 AWG?

No — and this is the trap the size charts skip. A lug crimped onto 2 AWG is far wider than the cable itself; barrel plus inspection window often exceeds 15mm, which calls for 3/4 inch. Use 1/2 inch along the cable run and step up at the termination.

How much does 1/2 inch heat shrink shrink down to?

12.7mm expanded recovers to approximately 6.4mm at full heat. At battery-cable diameters the recovered figure is what decides whether the tube grips the jacket or slides on it, so check it against the cable OD before cutting.

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

No. Battery cable sees acid, salt spray and road film, none of which a single-wall tube seals against. Use the Helixal 1/2" 3:1 Dual Wall on battery work; keep this 2:1 for dry indoor cable runs and identification.

How far does a 120ft roll of 1/2 inch go?

Each roll holds 120 feet. A full battery relocation typically consumes 6–10 feet at this diameter, so one roll covers many jobs — the practical alternative to buying short lengths repeatedly.

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.

Will 1/2" tubing work on a 1000V string circuit?

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 1/2" (12.7mm) 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 bundling and marking 2–4 AWG cable. If a supplier offers you 1000V rated tubing, ask which standard, edition and file number backs the number.

2:1 · 1/2" · 120 ft● LIVE SPEC

UL 224 RecognizedFlame Retardant600V Rated HELIXAL 2:1 Standard Heat Shrink Tubing 1/2" (12.7mm) — 120ft Roll

BLACK · 1/2" · 120 FTHELIXAL · ISO 9001

2:1 Single Wall · UL 224 Recognized

1/2"
2:1 Heat Shrink

Q: What cable does 1/2 inch heat shrink tubing fit?

Helixal 1/2" 2:1 has a 12.7mm expanded bore recovering to about 6.4mm. It slides over bare 2–4 AWG battery cable and covers crimped 12–10 AWG splice barrels, which measure 9–11mm. ABYC E-11 Table XI rates 4 AWG at 70A and 2 AWG at 95A.

Fits2–4 AWG12.7mm

1/2 inch heat shrink tubing fits 2–4 AWG wire — the gauge used for primary battery cables, high-current alternator feeds, LiFePO4 battery bank interconnects, and 200A+ power distribution wiring. ABYC E-11 Table XI rates 4 AWG at 70A and 2 AWG at 95A; connections at these current levels are typically high-dollar crimped terminations where proper insulation and sealing directly affect system reliability. At 12.7mm expanded diameter, this tube slides freely over 2 and 4 AWG conductors and recovers to approximately 6.35mm. The 2:1 single-wall construction, qualified to UL 224, is the correct choice for dry indoor termination points in battery rooms and panels where the cable is protected and clean insulation is the priority. When battery cables route through an engine bay or are exposed to road salt, moisture, or outdoor conditions, the 3:1 dual-wall adhesive liner creates the sealed protection that single-wall tubing cannot provide. At 120 feet per roll, professional automotive fabricators and industrial electricians get outstanding per-foot value — enough for an entire vehicle build or LiFePO4 battery bank installation.

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

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Size1/2" · 12.7mm

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

$23.99120 ft spool

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SKU: B0FJHQTZWC · 1/2" (12.7mm) · 120 ft

Spec Sheet

1/2"
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

1/2"

Expanded diameter

Metric Size

12.7mm

Nominal

Roll Length

120 ft

Per spool

Wire Gauge

2–4 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 — 1/2 inch

Sized for the cable, defeated by the lug. The most common ordering mistake on the site.

1/2 inch (12.7mm) recovers to about 6.4mm. It slides over bare 2–4 AWG battery cable and covers crimped 12–10 AWG splice barrels at 9–11mm. ABYC E-11 Table XI rates 4 AWG at 70A and 2 AWG at 95A. And it is the size most often ordered for a job it cannot do, because the person ordering measured the cable when they should have measured what is crimped onto the end of it.

The 2 AWG lug problem, in numbers

Bare 2 AWG cable has an outside diameter around 10mm with its jacket. A 12.7mm tube passes over it comfortably, and every size chart that maps gauge to tubing will point you here. The chart is not wrong; it is answering a different question from the one the job is asking.

Crimp a lug onto that cable and the widest point is no longer the cable. A typical 2 AWG lug barrel runs 13–15mm, and once the palm and any inspection window are included the assembly commonly exceeds 15mm. Against a 12.7mm bore, that does not go on at all — not tightly, not with effort. It simply does not fit.

The working rule is to size from the widest point the tube must pass over and then verify the recovered diameter against the narrowest thing it must grip. On a terminated 2 AWG cable that means 3/4 inch over the lug and 1/2 inch along the run, which is why battery work is normally stocked as two diameters rather than one.

1/2 inch at a glance

Property	Figure	Why it matters
Expanded diameter	12.7mm (1/2")	Clears bare 2–4 AWG cable and 9–11mm splice barrels
Recovered diameter	≈6.4mm	Decides whether it grips the jacket or slides along it
Bare cable range	2–4 AWG	70A for 4 AWG, 95A for 2 AWG (ABYC E-11 Table XI)
A lug on 2 AWG measures	Often over 15mm	Past this bore entirely — that end needs 3/4 inch
Wall type	Single-wall polyolefin	Identification and abrasion protection in dry battery rooms
Roll length	120 ft	A battery relocation uses 6–10 ft, so one roll covers many builds

Measure the terminated assembly, not the cable. On battery work the two numbers are rarely within one tubing size of each other.

When 1/2 inch is not the size

01 · The cable is terminated

Barrel plus palm on 2 AWG regularly exceeds 15mm. Use 3/4 inch over the lug and keep 1/2 inch for the run behind it.

02 · The cable sees acid, salt or road film

Battery cable environments are the definition of wet-location. Use the 1/2" 3:1 Dual Wall there and keep this 2:1 for dry indoor runs.

03 · The jacket is under 7mm

A 6.4mm recovered wall will not grip a thinner jacket. Step down to 3/8 inch so the tube actually closes onto the cable.

04 · Above 600V

Rated 600V rms. On a 1000 Vdc system the conductor carries the insulation rating and heat shrink is a seal over an already-rated component.

Keep reading →3/4" 2:1 — the size for the lug end · 1/2" 3:1 Dual Wall — for battery work · Heat Shrink for Battery Terminals

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

See 1/2" In Use

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The Heat Shrink Roll Survived 14 Minutes in the Workshop

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Short

The Heat Shrink Roll Survived 14 Minutes in the Workshop

Size Reference

Expanded vs.
recovered.

Actual 1/2" tube at full expanded diameter (12.7mm) and after heat recovery. Use this as your fit reference before cutting.

Expanded: 12.7mm — slides over 2–4 AWG

Shrink ratio: 2:1 on full heat

1/2" 2:1 heat shrink tubing — expanded diameter 12.7mm versus recovered size reference diagram

1/2" · 12.7mm expanded2:1 recovery · fits 2–4 AWG

Use it on.

Cable Bundle Organization

Consolidates large wire bundles in audio systems, industrial panels, and equipment racks — providing clean mechanical protection and band identification.

Wire Termination Insulation

Insulates large wire terminations in dry indoor environments such as panel boards, UPS systems, and large inverter installations.

Audio & AV Cable Management

Used on subwoofer feeds, amplifier power wiring, and AV distribution cables in home theater and commercial audio installations.

Industrial Panel Harnesses

Provides strain relief and band identification for large wire harnesses at the entry and exit points of industrial control panels.

UPS & Battery Backup Wiring

Covers large battery cable connections and bus bar leads on UPS systems and battery backup installations in data centers and facilities.

Conduit Entry Finishing

Provides a clean protective sleeve at conduit entry and exit points where cables transition between raceways and panels indoors.

Size Guide

1/2" Questions.

Technical Guides

From the Blog

All Guides →

Free Tool

1/2" 3:1 Dual Wall →Waterproof adhesive-lined 1/2" 3:1 Short Pack →10ft trial/repair pack

All 13 sizes.

View line overview →

3/32"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

Current1/2"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

1/2"
2:1 Heat Shrink

1/2"
data sheet.

What the
trade says.

Sized for the cable, defeated by the lug. The most common ordering mistake on the site.

The 2 AWG lug problem, in numbers

1/2 inch at a glance

When 1/2 inch is not the size

How it shrinks.

Measure & Select

Cut & Thread

Apply Heat

Inspect

See 1/2" In Use

The Heat Shrink Roll Survived 14 Minutes in the Workshop

Expanded vs.
recovered.

Use it on.

Cable Bundle Organization

Wire Termination Insulation

Audio & AV Cable Management

Industrial Panel Harnesses

UPS & Battery Backup Wiring

Conduit Entry Finishing

1/2" Questions.

From the Blog

Heat Shrink Size Calculator

2:1 vs 3:1 vs 4:1 Heat Shrink Ratio Guide

2:1 Heat Shrink Uses — Bundling & More

Size Chart & Selection Guide

Heat Shrink vs Electrical Tape

Best Heat Shrink Tubing 2026

All 13 sizes.

1/2" 2:1 Heat Shrink

1/2" data sheet.

What the trade says.

Sized for the cable, defeated by the lug. The most common ordering mistake on the site.

The 2 AWG lug problem, in numbers

1/2 inch at a glance

When 1/2 inch is not the size

How it shrinks.

Measure & Select

Cut & Thread

Apply Heat

Inspect

See 1/2" In Use

The Heat Shrink Roll Survived 14 Minutes in the Workshop

Expanded vs. recovered.

Use it on.

Cable Bundle Organization

Wire Termination Insulation

Audio & AV Cable Management

Industrial Panel Harnesses

UPS & Battery Backup Wiring

Conduit Entry Finishing

1/2" Questions.

From the Blog

Heat Shrink Size Calculator

2:1 vs 3:1 vs 4:1 Heat Shrink Ratio Guide

2:1 Heat Shrink Uses — Bundling & More

Size Chart & Selection Guide

Heat Shrink vs Electrical Tape

Best Heat Shrink Tubing 2026

All 13 sizes.

1/2"
2:1 Heat Shrink

1/2"
data sheet.

What the
trade says.

Expanded vs.
recovered.