3FL4
Composite long-rod insulator 3FL4, SML 120 kN, 72.5 – 550 kV, HTV silicone on ECR FRP rod, suspension & tension
3FL4
- Specified mechanical load (SML) 120 kN, routine test load (RTL) 60 kN — every insulator routine-tested before leaving the factory
- One-piece HTV silicone rubber housing, direct-injection molded onto the rod — prevents partial discharges and gives hydrophobicity transfer for highest pollution performance
- Boron-free ECR glass FRP core rod — brittle-fracture resistant, hydrolysis- and acid-resistant
- Two alternating-shed housing profiles: creepage factor 3.0 (sheds Ø 102/71 mm non-overmoulded, Ø 101/71 mm overmoulded) or 4.1 (sheds Ø 134/103 mm), both on 52 mm shed spacing
- Section lengths from 821 mm to 6,125 mm in 52 mm increments cover systems 60 kV through 550 kV; forged-steel end fittings per IEC 61466-1 and ANSI C29.2, also available combined with line hardware and line surge arresters
Sign in to see your price, availability and framework terms for 3FL4.
Horizon-3 pattern: this exact page gains commerce powers on sign-in — the URL never changes.
SIMULATED · ASK-AN-EXPERT PILOT DEMO
Ask an expert about 3FL4
15 minutes with the right arresters & insulators specialist — question in, booked call out. No email archaeology.
Checking availability…
3FL4 covers 72.5–550 kV of the long-rod & station post range (≤ 800 kV across the category, √ scale).
Specifications
Main
| Product family | 3FL4 |
| Product type | Composite long-rod insulator |
| Application | Suspension and tension on overhead lines |
| Housing | One-piece HTV silicone rubber, direct injection molding onto the rod |
Ratings
| Specified mechanical load (SML) | 120 kN (SML class of the 3FL4 size; 3FL family spans 70 – 630 kN) |
| Routine test load (RTL) | 60 kN |
| Highest voltage for equipment (Um) | 72.5 – 550 kV (nominal system voltages 60 – 500 kV) |
| Section length | 821 – 6,125 mm (with socket and ball), length increments 52 mm |
| Sealing system | System A (triple point directly overmoulded in HTV silicone, family up to 210 kN) or System B (gap fully sealed with elastic silicone gel, family 100 – 630 kN) |
| Creepage factor (CF) | 3.0 or 4.1 (two alternative shed profiles) |
Mechanical / environment
| Core | ECR glass (boron-free) FRP rod — brittle-fracture resistant, hydrolysis- and acid-resistant |
| Shed profile CF 3.0 | Alternating sheds Ø 102 / 71 mm (Ø 101 / 71 mm on the overmoulded design), 52 mm spacing (26/26), 4 mm shed tip, Ø 24 mm housing over rod |
| Shed profile CF 4.1 | Alternating sheds Ø 134 / 103 mm, 52 mm spacing (28/24), 4 mm shed tip, Ø 24 mm housing over rod |
| End fittings | Forged steel per IEC 61466-1 and ANSI C29.2 |
| Pollution performance | HTV silicone with hydrophobicity transfer mechanism |
| Field control | Integrated grading ring reduces electrical field stress; external corona rings included as standard for system voltages above 170 kV |
Standards & certifications
| Design & type testing | IEC 61109, ANSI C29.11, ANSI C29.12, CSA C411.4-16 (latest versions) |
| End fittings | IEC 61466-1, ANSI C29.2 |
Options & variants
Selected lengths from the Siemens Power Engineering Guide table 'Technical data 3FL3 and 3FL4' (socket-and-ball end fittings, standard-creepage catalog code 3); lengths in 52 mm increments up to 6,125 mm, intermediate/shorter/longer lengths on request. -1XS1 types from 245 kV include a corona ring (Ø 210 mm, HV side). Housing-profile alternatives (CF 3.0 / 4.1, overmoulded / non-overmoulded) per drawings 492-00012 / 492-00013 / 492-05000 / 492-05004 and overview 802-69312.
| Type | Um | LIWV (1.2/50 µs, dry) | PFWV (50 Hz, 1 min, wet) | Arcing distance | Creepage distance (std / extra-high) | Housing length | Section length |
|---|---|---|---|---|---|---|---|
| 3FL4 061-3SB11-1XX1 | < 72.5 kV | 449 kV | 160 kV | 644 mm | 1,706 / 2,291 mm | 614 mm | 821 mm |
| 3FL4 108-3SB11-1XX1 | 123 kV | 690 kV | 340 kV | 1,112 mm | 3,169 / 4,310 mm | 1,082 mm | 1,289 mm |
| 3FL4 124-3SB11-1XX1 | 145 kV | 771 kV | 400 kV | 1,268 mm | 3,657 / 4,983 mm | 1,238 mm | 1,445 mm |
| 3FL4 145-3SB11-1XX1 | 170 kV | 882 kV | 469 kV | 1,476 mm | 4,307 / 5,881 mm | 1,446 mm | 1,653 mm |
| 3FL4 202-3SB11-1XS1 | 245 kV | 1,220 kV | 571 kV | 2,003 mm | 6,096 / 8,348 mm | 2,018 mm | 2,225 mm |
Documents & downloads
Flyer 3FL long rod insulators — Composite technology up to 800 kV (Siemens Energy, 2021)
Catalog excerpt 3FL silicone long rod insulators — Power Engineering Guide (Edition 7.1) section 4.10 with 3FL2 – 3FL6 ratings and 3FL2/3FL3/3FL4 technical data tables
Drawing Housing profile 3FL4___-3__11-1XX9, CF 3.0, non-overmoulded (492-00012, customer version)
Drawing Housing profile 3FL4___-4__11-1XX9, CF 4.1, non-overmoulded (492-00013, customer version)
Drawing Housing profile 3FL4___-3__11-1XX1, CF 3.0, overmoulded (492-05000, customer version)
Also covered in the technical library
Brochure Our portfolio of surge arresters & composite insulators — Siemens Energy
Related products
3FH 
3FL2
Composite hollow-core insulators 3FH — apparatus housings for breakers, bushings and instrument transformers; detailed ratings on request
Apparatus housings · Composite hollow-core · Ratings on request Datasheet · Dimensions ↓ 3FL-HVDCHVDC converter tension insulators, 3FL composite long-rod platform, one-piece HTV silicone housing on ECR glass FRP rod
HVDC converter tension duty · 3FL composite long-rod platform · Silicone housing Datasheet · Dimensions ↓ 3FL2