High-Temp Fiberglass Sleeving

Q: What does "Class H insulation" actually mean?
Class H is an electrical insulation rating for materials that can handle continuous exposure to 180°C, used across the cable, motor and transformer industry. This sleeving is Class H rated with a 250°C maximum, so it holds up in the hottest spots of an engine bay without breaking down.

Q: Can I use this to wrap exhaust headers or turbo piping?
No — this sleeving is rated to 200°C continuous (250°C maximum), well below exhaust manifold and turbo surface temperatures of 500°C or more. For exhaust wrap you need a purpose-built basalt or ceramic-fibre header wrap rated for that heat range; this product is for wiring and hose protection, not direct exhaust contact.

Q: What does UL 1441 (VW-1) actually mean?
UL 1441 is the safety standard covering flammability and electrical resistance of coated sleeving materials. VW-1 is the vertical flame-spread test this sleeving passes — the material self-extinguishes rather than carrying flame along its length, and it also meets UL 1441's volume resistivity requirement for electrical insulation.

Q: How flexible is it — will it handle tight bends around a wiring harness?
Yes. The braided fiberglass construction flexes around bends and corners without kinking or cracking, which is why it's commonly run along wiring looms rather than just straight sections.

Q: What size do I need for my wiring bundle?
Match the internal diameter to the bundle you're covering — undersized sleeving is a fight to pull over, oversized sleeving sits loose and protects less. Check the size guide above against your bundle's outer diameter, and round up if you're between sizes.

Q: Does it protect wiring exposed to engine oil?
It's tested for dielectric performance after oil exposure — manufacturer data shows it retains around half of its original dielectric strength afterward, so it's not designed as a long-term oil-immersion barrier. Brief oil exposure is fine; it isn't sold as fuel-line protection, so keep it on the wiring side and use a dedicated fuel-rated line for fuel.

Q: How do I fit it and keep it in place?
Slide it over the wire or hose before you terminate the ends — it has to go on before connectors or fittings are crimped on. Once positioned, secure the ends with heat-resistant tape, cable ties or heat shrink so it doesn't ride back along the loom.

Q: Is it flame resistant on its own, or does it need extra fireproofing?
The silicone-coated fiberglass braid is self-extinguishing under the UL 1441 VW-1 test, so it won't carry a flame along the sleeve. It's a protective layer for the wiring underneath, not a substitute for correctly rated cable insulation.

Q: What's the minimum and maximum temperature it handles?
Continuous use is rated from -40°C to 200°C, covering everything from a cold start to sustained engine bay heat, with a maximum (short-term) rating of 250°C for hot spots.

Q: How is it sold — can I order odd lengths?
Sold per metre in each diameter — order the exact length you need for the run, cut to size.