Composite long-rod insulator 3FL5, SML 160 kN, 72.5 – 550 kV, one-piece HTV silicone housing on ECR FRP rod, suspension & tension
3FL5
- Specified mechanical load (SML) 160 kN, routine test load (RTL) 80 kN — every insulator routine-tested at ≥ 50% of SML for at least 10 seconds before leaving the factory
- One-piece HTV silicone rubber housing, one-shot injection molded over the rod and triple junction point — no traditional sealing system, no moisture ingress path, only one internal interface in the whole insulator
- Boron-free ECR glass FRP core rod — brittle-fracture resistant, hydrolysis- and acid-resistant
- Electrical withstand values match the 3FL3/3FL4 series at equal housing lengths; section lengths and weights are higher due to the larger size-20 end fittings (socket and ball 20, clevis 19L/19N, tongue 19L/19N, Y-clevis 22, eye 25/30)
- Integrated grading ring keeps field stress and RIV low — applicable without external corona rings up to 170 kV; rings are a standard feature above (Ø210/Ø330/Ø420 mm by line voltage)
Overhead transmission line suspension stringsOverhead transmission line tension stringsHigh-pollution coastal and industrial areasLine surge arrester assemblies
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3FL5 covers 72.5–550 kV of the long-rod & station post range (≤ 800 kV across the category, √ scale).
Specifications
Main
| Product family | 3FL5 |
| Product type | Composite (silicone) long-rod insulator |
| Application | Suspension and tension on overhead lines |
| Housing | One-piece HTV silicone rubber, one-shot injection molding onto the rod |
| Hierarchy load class | 3FL5 insulators ≤ 160 kN (official product hierarchy, Tension and Suspension Insulators 3FL) |
Ratings
| Specified mechanical load (SML) | 160 kN (3FL family spans 70 – 630 kN) |
| Routine test load (RTL) | 80 kN |
| Highest voltage for equipment (Um) | 72.5 – 550 kV (nominal system voltages 60 – 500 kV) |
| Section length | 878 – 6,182 mm per the 3FL5/3FL6 technical data table (socket and ball; the family maximum-values table quotes 871 – 6,125 mm); length increments 52 mm, other lengths on request |
| Creepage variants | Standard creepage (catalog code 3) or extra-high creepage (catalog code 4) |
| Sealing system | System A (triple point directly overmoulded, family up to 210 kN) or System B (gap fully sealed with elastic silicone gel, family 100 – 630 kN) |
Representative ratings (socket and ball, standard creepage)
| Um < 72.5 kV | LIWL 449 kV · PFWL 160 kV · arcing 643 mm · creepage 1,702 / 2,288 mm (std / extra-high) · section length 878 mm · ~5.2 kg (3FL5 061-3SB21-1XX1) |
| Um 123 kV | LIWL 664 kV · PFWL 320 kV · arcing 1,059 mm · creepage 3,003 / 4,082 mm · section length 1,294 mm · ~6.3 kg (3FL5 103-3SB21-1XX1) |
| Um 245 kV | LIWL 1,220 kV · PFWL 571 kV · arcing 2,002 mm · creepage 6,092 / 8,344 mm · section length 2,282 mm · Ø210 mm corona ring HV side (3FL5 202-3SB21-1XS1) |
| Um 420 kV | LIWL 1,971 kV · SIWL 1,229 kV · PFWL 732 kV · arcing 3,398 mm · creepage 10,645 / 14,625 mm · section length 3,738 mm · Ø210 / Ø330 mm rings (3FL5 347-3SB21-1SM1) |
| Um 550 kV | LIWL 2,284 kV · SIWL 1,415 kV · PFWL 806 kV · arcing 4,361 mm · creepage 13,735 / 18,888 mm · section length 4,726 mm · Ø210 / Ø420 mm rings (3FL5 446-3SB21-1SL1) |
Mechanical / environment
| Core | ECR glass (boron-free) FRP rod — brittle-fracture resistant, hydrolysis- and acid-resistant |
| End fittings | Hot-dip galvanized forged steel or ductile cast iron, monitored circumferential crimping; couplings for 160 kN: Socket and Ball 20 (IEC 60120), Clevis 19L/19N and Tongue 19L/19N (IEC 60471 / IEC 61466-1), Y-clevis 22, Eye 25 or 30 (IEC 61466-1) |
| End-fitting connection lengths V | Ball 20 = 135 mm · Socket 20 = 129 mm · Clevis 19L = 145 mm · Tongue 19L = 144 mm · Y-clevis 22 = 156 mm · Eye 25 = 153 mm |
| Field control | Integrated grading ring in the junction; external corona rings standard above 170 kV: Ø210 mm line end at 245 kV, Ø330 mm at 300/362 kV, Ø210 ground + Ø330 line at 420 kV, Ø210 ground + Ø420 line at 550 kV |
| Pollution performance | Strongly hydrophobic HTV silicone rubber — reliable even in coastal salt fog and dust-laden industrial air |
Standards & certifications
| Design & type testing | IEC 61109, IEC 62217, IEC 60815, IEC 61466-1/-2; latest flyer additionally states ANSI C29.11, ANSI C29.12, CSA C411.4-16 |
| Routine test | Tensile load ≥ 50% of SML for ≥ 10 seconds on every insulator |
Documents & downloads
Catalog excerpt 3FL silicone long rod insulators — Power Engineering Guide (Edition 7.1) section 4.10 with 3FL2 – 3FL6 ratings and the 3FL5/3FL6 technical data table
Flyer 3FL long rod insulators — Composite technology up to 800 kV
Brochure Our portfolio of surge arresters & composite insulators — overhead line solutions incl. 3FL composite insulators up to 800 kV (current online edition)
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