If you're wrapping an automotive or electronics harness that has to pass a fire spec, "flame retardant" is not a single thing — buyers get tripped up because two different UL standards and a temperature-class system all appear on the same datasheet. Here is how to read them and specify the right tape.
UL 510 vs UL 94 V-0 — they answer different questions
- UL 510 is the standard for electrical insulating tape. A tape "UL Recognized to UL 510" has been evaluated for insulation and flame performance as a tape. Drawings usually call this out by name.
- UL 94 V-0 is a material flammability rating. V-0 means the material self-extinguishes within 10 seconds after the flame is removed and does not drip flaming particles — the top tier most people mean by "flame retardant".
A good harness tape states both: Meets UL 510 and Passes UL 94 V-0. Be cautious of any supplier marketing tape as "fireproof" — that word is not used in this industry.
Match the temperature class: LV 312 T1–T4
| Class | Range | Where it goes |
|---|---|---|
| T1 (Class A) | −40 to 85 °C | Passenger cabin, dashboard |
| T2 (Class B) | −40 to 105 °C | Engine-bay periphery |
| T3 (Class C) | −40 to 125 °C | Engine-bay core (abrasion-resistant PET) |
| T4 (Class D) | −40 to 150 °C | Against engine / turbo (glass cloth) |
Spec the class first, then the flame rating. A typical OEM request reads: "Class D tape for under-hood applications."
Don't forget zero-halogen
For rail, aerospace and premium automotive, ask for zero-halogen flame-retardant grades — they self-extinguish and produce no toxic halogen fumes when heated. It is often a hard requirement, so confirm it up front.
A practical spec checklist
- Base material + temperature class (LV 312 T1–T4)
- Flame spec: Meets UL 510 and/or Passes UL 94 V-0
- Zero-halogen? (rail / aero / premium auto)
- Hand-tearable / clean-tear for line speed
- Width, length, colour and volume
See our flame retardant tape and automotive wire harness tape.
FAQ
What does UL 94 V-0 mean?
The material self-extinguishes within 10 seconds after the flame source is removed and does not drip flaming particles — the top consumer flame-retardant tier.
Is UL 510 the same as UL 94 V-0?
No. UL 510 rates the tape as an electrical insulating tape; UL 94 V-0 rates the material's flammability. A good FR harness tape meets both.
Which flame-retardant tape should I use under the hood?
Choose an LV 312 T3/T4 (Class C/D) grade that meets UL 510 and passes UL 94 V-0. EJOY supplies these, including zero-halogen options, with free samples.