Most winding failures start at the lead exit — the point where enameled magnet wire transitions to an insulated lead, and where heat, vibration, oil and dielectric stress all concentrate. This page maps each failure mode to the sleeving construction that survives it.
Start from the failure mode, not the catalogue. Each card below is a failure point we see again and again in motor and generator plants.
Dielectric breakdown and creepage tracking start where the enamel wire leaves the overhang. Silicone fiberglass sleeving with 4–20 kV dielectric strength (up to 50 kV on selected constructions) gives the lead a tracking-resistant, flexible barrier.
Class H (180 °C / 356 °F) windings need insulation that stays flexible after years of thermal cycling. Silicone fiberglass sleeving is rated −60 ~ +200 °C (−76 ~ 392 °F), with 220 °C (428 °F) peak on selected constructions.
In oil-filled housings the insulation is permanently submerged. Acrylic-coated fiberglass (ARG) holds its dielectric and mechanical properties in oil where many coatings swell or extract — the grade behind our UL UZFT2 / CUL UZFT8 recognition.
Leads pressed into terminal boxes and clipped against housings need a barrier that resists cut-through. Woven fiberglass distributes point loads where a solid extruded wall can be nicked through.
Every row pairs a real motor position with the working condition at that spot and the WCW construction we recommend for it.
| Position | Working Condition | Recommended WCW Material | Key Rating |
|---|---|---|---|
| Motor lead wires | Dielectric stress, flexing at the exit | SGS / SRS silicone fiberglass sleeving | 4–20 kV · −60 ~ +200 °C (−76 ~ 392 °F) |
| Winding overhang | Class H heat, thermal aging, batch consistency | SGS / SRS silicone fiberglass sleeving, high-breakdown grades | Class H 180 °C (356 °F), 220 °C (428 °F) peak selected |
| Oil-cooled & hermetic compressor motors | Continuous oil immersion, dimensional change | ARG acrylic fiberglass sleeving | UL UZFT2 / CUL UZFT8 · −60 ~ +155 °C (−76 ~ 311 °F) |
| Leads needing a tough outer surface | Abrasion at the exit, handling damage | GS sleeving — inside rubber / outside fiber | 7000 V avg / 6000 V min · UL 1441 E233804 (GS-WCW-70) |
| Terminal box & control cable | Assembly crush, chafe at the gland | PET expandable braided sleeving | −60 ~ +155 °C (−76 ~ 311 °F) · cut & abrasion resistant |
| Positions near heat sources above 200 °C | Radiant heat, exhaust-adjacent routing | TGS-1W-600C high-temperature fiberglass sleeving | −60 ~ +600 °C (−76 ~ 1112 °F) |
Six constructions cover every position on the motor — from the lead exit to the terminal box.
The motor workhorse: silicone-coated fiberglass, flexible at −60 °C, 4–20 kV standard (up to 50 kV selected), UL 1441 with UL VW-1.
Smooth silicone-rubber outer skin over a fiberglass core; the E233803 style for lead protection where a sealed feel matters.
Rubber inside, braid outside: a tough outer surface for leads that get handled. 7000 V avg / 6000 V min, UL 1441 E233804 (GS-WCW-70).
The oil-cooled motor grade. Holds dielectric and mechanical properties under continuous oil immersion — UL UZFT2 / CUL UZFT8.
Bundling, identification and cut resistance in the terminal box; expands over connectors, cuts cleanly.
For zones no silicone can reach — heater-adjacent and exhaust-adjacent routing up to 600 °C (1112 °F).
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