PEEK, PPS, PEI, PTFE and PVDF are UL94 V-0 as they come; PA66, PC, PBT and ABS need a flame-retardant grade; POM, PE and PMMA stay HB. The chart, the pass criteria and the thickness rule are below — and the part can be machined in the plastic the rating calls for.
EKINSUN machines plastic parts for electrical panels, switchgear and enclosures in our own CNC factory, from 1 piece — and the first line on those drawings is usually the flame rating. The chart below gives the UL94 class each common engineering plastic reaches in its standard form, and which ones reach V-0 only as a special flame-retardant grade.
Which plastics are V-0 without additives? PEEK, PPS, PEI, PTFE and PVDF. PA66, PC, PBT and ABS reach V-0 only as flame-retardant grades; POM, PE and PMMA stay HB.
PEEK, PPS, PEI, PTFE and PVDF are V-0 in their standard form; the other plastics here burn as V-2 or HB unless a flame-retardant grade is named on the drawing. The class shown is the usual rating of the material family, not of one grade.
| Material | Standard (unmodified) grade | Flame-retardant grade available? | Typical parts in electrical equipment |
|---|---|---|---|
| PEEK | V-0 — test data below | Not needed | Operating handles, interlock slides, insulating bushings |
| PPS | V-0 | Not needed | Terminal blocks, coil bobbins, connector bodies |
| PEI | V-0 | Not needed | Insulators, connector housings |
| PTFE | V-0 | Not needed | Insulating spacers, cable bushings |
| PVDF | V-0 | Not needed | Cable insulation parts, chemical-duty housings |
| PA66 | V-2 | Yes — V-0 grades, often glass-filled | Cable clamps, terminal covers, handles |
| PA6 / cast PA6 | HB to V-2 | Yes, for injection grades | Guides, rollers — rarely where V-0 is specified |
| PC | V-2 | Yes — V-0 grades | Covers, windows, indicator lenses |
| PBT | HB | Yes — V-0 grades, usually glass-filled | Relay and switch housings |
| ABS | HB | Yes — V-0 grades | Enclosures, front panels |
| POM (acetal) | HB | Rarely — choose another plastic for V-0 | Gears, latches — not for V-0 duty |
| PP | HB | Yes — V-2 and V-0 grades | Covers, trays |
| PE / UHMW-PE | HB | Rarely | Wear strips — not for V-0 duty |
| PMMA (acrylic) | HB | Rarely | Windows — use a V-0 PC instead |
A specific grade's rating holds only at the thickness it was tested at, or thicker — check the data sheet of the grade at your wall thickness. Glass fibre changes the rating of some plastics, so a PA66 GF30 and an unfilled PA66 can differ.
Need the part in a V-0 plastic? Send a drawing, a sketch or the old part. EKINSUN machines PEEK, PPS, PEI, PTFE and flame-retardant PA66 or PC parts from 1 piece; larger runs can be injection-moulded at our partner factories. The more pieces, the lower the unit price. Quote within 12 hours.
UL94 V-0 is the strictest of the three vertical-burn classes: each of five test bars must stop burning within 10 seconds after each of two flame applications, and no burning drip may ignite the cotton below. V-1 allows 30 seconds per flame; V-2 allows 30 seconds and burning drips.
| Criterion | V-0 | V-1 | V-2 |
|---|---|---|---|
| After-flame time of one bar, t1 or t2 | ≤ 10 s | ≤ 30 s | ≤ 30 s |
| Total after-flame time of all 5 bars (t1 + t2) | ≤ 50 s | ≤ 250 s | ≤ 250 s |
| After-flame + afterglow after the 2nd flame (t2 + t3), per bar | ≤ 30 s | ≤ 60 s | ≤ 60 s |
| Burning or glowing up to the holding clamp | No | No | No |
| Burning drips ignite the cotton below | No | No | Allowed |
HB is the horizontal test and the lowest class: the bar may keep burning, but slowly — at most 40 mm per minute for bars 3 to 13 mm thick, at most 75 mm per minute for bars under 3 mm, or it must stop before the 100 mm mark. A drawing that only says "flame retardant" leaves the class open; write V-0, V-1, V-2 or HB and the thickness.
A plastic rated V-0 at 3.2 mm is not automatically V-0 at 1.5 mm, because a thin bar heats through faster. The PEEK from our material supply shows it: five 3.2 mm bars burned 12 seconds in total, five 1.5 mm bars 42.1 seconds — both inside the 50-second V-0 limit, but the thin bars used most of the margin, with one bar at 8.7 seconds against the 10-second limit. The full bar-by-bar data is on the PEEK machining page.
For a machined part, the thinnest wall decides. A handle with 6 mm walls and a 1 mm web is a 1 mm part as far as the rating goes — tell us the thinnest section when you ask for V-0.
"UL94 V-0" on a drawing usually means the material burns to the V-0 criteria in the UL94 test. A UL listing — a recognised-component file — is a separate certification that the material maker holds for one named grade. If your drawing or your end customer asks for a UL-listed material, say so in the enquiry: the grade has to be chosen for it from the start, and it limits which plastics and stock sizes can be used.
EKINSUN is a manufacturer of custom parts to drawing or from a sample: a flame-rated plastic is one line on a part that also has threads, bores and tolerances. The table separates what an electrical wholesaler stocks from what has to be made.
| What you need | On the shelf? | What we do |
|---|---|---|
| A standard knob, handle or cable gland in a V-0 plastic, sold as a catalogue item | Yes — electrical wholesalers | Buy it from stock there if you need one today — or contact us, we may have it in stock. |
| A replacement handle, position indicator or interlock slide for switchgear that is no longer made | No | Machined in PEEK from the old part or a drawing, from 1 piece — see obsolete parts. |
| Insulators, bushings or spacers in PEEK, PPS, PEI or PTFE to your drawing | No — rod and plate only | Machined in our own CNC factory from 1 piece; the more pieces, the lower the unit price. |
| Several hundred identical V-0 parts | Not in your shape | Machined, or injection-moulded in a V-0 grade at our partner factories — quoted both ways. |
| A gear or interlock plate that carries the mechanism load | No | Often better in steel: machined and zinc-plated, from 1 piece — see custom spur gears. |
A part for equipment that is no longer made? Send the old part or photos with a few caliper readings, and the flame rating the panel needs. We machine it in PEEK or another V-0 plastic from 1 piece, metal parts of the same mechanism alongside; quote within 12 hours. How it works: parts made from a sample.
Yes. PTFE is rated V-0 and does not need a flame-retardant grade; it is soft, so it suits insulating spacers and bushings more than load-bearing parts.
Standard PA66 is usually V-2 and cast PA6 is HB to V-2. V-0 needs a flame-retardant nylon grade, often glass-filled, and that grade has to be named on the drawing.
Two stricter classes for enclosure walls, tested with a larger flame on bars and plates. Machined parts such as handles, insulators and bushings are specified to V-0 instead.
Related pages: engineering plastics comparison chart; plastic trade names; PEEK machining; plastic insulating washers; custom plastic parts.
PEEK, PPS, PEI, PTFE and PVDF reach UL94 V-0 in their standard form. PA66, PC, PBT, ABS and PP reach V-0 only as flame-retardant grades; POM, PE and PMMA stay HB.
Yes. PEEK reaches UL94 V-0 without flame-retardant additives; test bars of the PEEK from our material supply rated V-0 at both 1.5 mm and 3.2 mm thickness.
No. POM is rated HB and is rarely offered as V-0; for a V-0 part choose a flame-retardant PA66 or PBT, or PEEK.
No. A UL94 rating holds at the thickness it was tested at, or thicker; the thinnest wall of the part decides.
No. V-0 is the result of the UL94 burn test; a UL listing is a separate certification held by the material maker for one named grade. Ask for it in the enquiry if you need it.
Yes. EKINSUN machines single parts in PEEK, PPS, PEI or PTFE from the old part or a drawing, from 1 piece, quoted within 12 hours.
2 tables on one printable sheet: UL94 rating of 14 engineering plastics and the V-0 / V-1 / V-2 pass criteria.
Download PDF ↓Quote within 12 hours: drawing, sketch or the old part, the flame rating and the quantity.
// UL94 in short
or by email: [email protected]
Handles, insulators, bushings and interlock parts in PEEK, PPS, PEI, PTFE or flame-retardant PA66, machined to drawing or from the old part — from 1 piece, quote within 12 hours.