Flame Retardant PETG V0: When a UL94 Rating Is Worth the Extra Cost
V0-rated PETG offers something regular PETG does not claim: a UL94 V0 rating as a self-extinguishing material. This guide covers what that rating means, which electronics enclosures can benefit, and when you should stick with standard PETG and keep the difference.
Find My 3D Printer editorial team·Published November 8, 2026·Manufacturer documentation, no hands-on tests claimed
The short answer
Flame retardant PETG V0 is a self-extinguishing filament: according to Prusa's documentation, Prusament PETG V0 earned a UL94 V0 classification from UL using the IEC 60695-11-10 method. It is worth the extra cost over standard PETG mainly for electronics housings and insulating parts where a material rating is actually required. For parts without that requirement, standard PETG is the better fit, since Prusa lists slightly worse mechanical properties for the V0 version. The rating applies to the material and does not by itself make a part or device compliant.
What a UL94 V0 Rating Actually Tells You
V0 PETG is a PETG designed to put itself out. The Prusa Knowledge Base explains how its Prusament PETG V0 does this: when the material starts burning, a carbonized crust forms on the surface. That crust keeps oxygen from getting in and feeding the flame, and the fire eventually goes out.
According to the same documentation, Prusa had UL evaluate the filament using the IEC 60695-11-10 method. The result was a UL94 V0 classification for both of its colors, backed by a Blue Card, the certificate UL issues. Prusa calls it the only UL-certified self-extinguishing PETG in the world. That is the manufacturer's own wording, so check what else is on the market when you are ready to buy.
Keep the scope of the rating in mind. It describes how a material behaves under a specific test method. It says nothing about your finished part, its infill, or the device inside it, and it does not make your product UL listed. A V0 label on another brand's spool is not proof either. Ask for the certificate and confirm it covers the exact product and color you are buying.
Electronics Enclosures Where the Extra Cost Makes Sense
Prusa points this filament at a specific job: housings and insulating parts in electronics. Its sample prints include insulation parts and machine parts. That is where the material makes its case, because the property you are paying for supports what the part is there to do.
The extra cost is easiest to justify when someone requires a rating in writing, such as a customer spec, a technical file for a small piece of equipment, or an internal shop rule. It can also make sense for a cover or insulating part that stays in place around powered electronics, if your own risk assessment calls for a self-extinguishing material. When that happens, file the certificate and the spool details with the part's records.
The filament alone does not get you compliance. If your device falls under regulations, or connects to wall power or a battery pack, material choice does not replace proper design or review by a qualified professional. ESD filament solves a different problem, by the way: static discharge rather than how a material behaves in a fire.
When Standard PETG Is the Smarter Buy
For many projects, standard PETG does the job. A prototype Arduino enclosure, a cable holder, or a shop organizer usually has no rating requirement, so a specialty filament adds cost without a benefit you could point to.
Standard PETG also beats its V0 sibling on one point that matters. Prusa's documentation lists slightly worse mechanical properties for PETG V0 than for regular PETG. On a clamp, a bracket, or another mechanical part with no flame requirement, you would pay more and give up a little performance. Prusa also describes regular PETG as tough and suited to most indoor and outdoor uses, as long as temperatures stay below 80 °C.
A practical workflow is to split the job in two. Prove out shapes and fits in standard PETG, then print the final version in V0 and recheck your dimensions, since a new material and profile can shift them. That way the pricier spool only goes into parts that really need the rating. To put a number on the gap for your own part, run both spools through the print cost calculator.
Print Settings and Prep from Prusa's Documentation
PETG V0 prints much like other PETG, with a few differences. Prusa recommends a nozzle temperature of 230 ±10 °C and lists a preheated bed at 80 °C, compared with 85 °C for regular PETG. The material has low shrinkage and warping, so Prusa says large objects are not a problem.
Moisture is the thing to watch. This filament is more hygroscopic than regular PETG and needs to stay as dry as possible. If you can't keep it dry, Prusa suggests drying it for 6 hours at 55 °C before use. Plan for sealed storage or a dryer before you order the spool, because damp filament will cost you time and failed parts.
For the print surface, go with a powder-coated satin or TXT sheet, cleaned with IPA while it is cold. Prusa advises against a smooth PEI build plate because the material bonds so strongly it can damage the surface, and its warranty does not cover that damage. If smooth is your only option, spread on a thin layer of glue stick. These numbers apply to Prusament, so follow the data sheet if you buy another brand.
Design Limits to Plan Around
PETG V0 keeps the usual PETG quirks. Prusa's page flags stringing and oozing, poor bridging, supports that are harder to remove, and worse detail than PLA, and it says the material is not suited to tiny parts. On an enclosure, that hits fine vent grilles, small snap clips, and tight connector cutouts first.
So design around it. Avoid long bridges over openings, orient the housing to cut down on supports, and leave a bit more clearance on fits. The surface also scratches more easily than PLA and can't be acetone-smoothed like ABS. On the plus side, it sands easily and comes off the printer with a glossy finish.
If you need a sturdier part, Prusa's PETG article suggests adding perimeters rather than infill. That tip is about strength, not flame behavior, so never assume a slicer setting earns a performance level the certificate does not describe. And if the part has to handle serious heat, compare other material families before you commit.
Sources and limits
- Prusa Knowledge Base — PETG V0
- Prusa Knowledge Base — PETG
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