Electrical Insulation · Standards Guide
NEMA vs IEC: Fiberglass Sleeving Standards
If you source fiberglass sleeving across borders, you quickly run into two parallel standards systems: NEMA (with UL and MIL specs) in North America and IEC internationally. They measure the same things — temperature, dielectric strength, flammability — but label them differently. This guide maps one onto the other so you can quote and qualify sleeving for any market.
In short (TL;DR)
NEMA HP3 / MIL-I-3190 + UL VW-1 is the North American route; IEC 60684 + IEC 60085 thermal class is the international route. Use the temperature rating (e.g. Class F = 155°C) as the common bridge, then confirm dielectric grade and flame certification separately.
NEMA vs IEC at a glance
| Topic | NEMA / North America | IEC / International |
|---|---|---|
| Governing body | NEMA / UL / MIL (North America) | IEC (international) |
| Sleeving spec | NEMA HP3, MIL-I-3190, UL VW-1 flame test | IEC 60684 (flexible insulating sleeving) |
| Thermal class | Often quoted in °C (130 / 155 / 200) | IEC 60085 classes (B / F / H / N) |
| Flame rating | UL VW-1 (vertical wire flame) | IEC 60684-2 flammability, often cross-listed to UL94 |
| Typical wall grades | Grade A-1 / A / B / C by dielectric strength | Specified by test voltage in IEC 60684-3 |
Temperature is the common bridge
The cleanest way to cross-reference is the thermal class. Whether a data sheet says "Class F" or "155°C", it points to the same IEC 60085 thermal class. Once temperature matches, line up the dielectric grade and the flame certification, which are the two areas where the systems diverge most.
Flammability: UL VW-1 vs IEC
Flame performance is certified differently on each side. UL VW-1 is the North American vertical-wire flame test for finished sleeving, while IEC uses IEC 60684-2. The base polymer is often also rated to UL94. When you specify a flame-retardant sleeve, name the exact certification your customer needs — VW-1 and UL94 V-0 are not interchangeable labels.
Frequently asked questions
What is the difference between NEMA and IEC sleeving standards?
NEMA (with UL and MIL specs) is the North American framework and IEC is the international one. Both classify flexible insulating sleeving by temperature rating, dielectric strength and flammability — but they use different document numbers and grade labels. For fiberglass sleeving, NEMA HP3 / MIL-I-3190 sit on the NEMA side and IEC 60684 on the IEC side.
Is UL VW-1 the same as IEC flammability?
Not exactly. UL VW-1 is a vertical-wire flame test common in North America, while IEC sleeving flammability is defined in IEC 60684-2. They test similar behaviour (self-extinguishing, no flaming drips) but are separate certifications. Many sleeving products are tested to both and also cross-listed to UL94 for the base material.
How do I cross-reference a Class F sleeve between NEMA and IEC?
Use temperature as the bridge. A Class F insulation system is 155°C under IEC 60085, and North American data sheets usually quote the same 155°C figure. Confirm the dielectric grade (NEMA grade vs IEC 60684-3 test voltage) and the flame certification (UL VW-1 vs IEC 60684-2) separately.
Which standard should an exporter design to?
Design to the destination market: UL VW-1 plus the relevant NEMA/MIL grade for North America, and IEC 60684 plus the IEC 60085 thermal class for international and European customers. Tentuo formulates acrylic sleeving coatings to support either route, including Class F (155°C) and UL VW-1 flame performance.
Need sleeving coatings certified for your market?
We formulate acrylic fiberglass-sleeve coatings for Class F (155°C) and UL VW-1 requirements, for both NEMA and IEC routes.