3FL2
Composite long-rod insulator 3FL2, ≤ 70 kN
3FL2
- Designed to meet the highest requirements in distribution power systems up to 72 kV — high lightning-impulse and power-frequency withstand voltages with a long creepage class (> 31 mm/kV)
- One-piece HTV silicone rubber housing made by one-shot injection molding — the triple point (FRP rod / metal fitting / silicone) is directly overmoulded and totally encapsulated, preventing moisture ingress without traditional sealing systems
- Boron-free, corrosion-resistant ECR glass FRP core rod — extremely high hydrolysis and acid resistance completely eliminates the risk of brittle fracture
- Six standardized 70 kN end fittings: ball 16 and socket 16A (IEC 60120), clevis 13L and tongue 13L (IEC 60471), Y-clevis 16 and eye 17 (IEC 61466-1) — 100 % exchangeable with existing insulators and line hardware
- Designed and type-tested in compliance with the latest versions of IEC 61109, ANSI C29.11, ANSI C29.12 and CSA C411.4-16
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3FL2 covers 12–72.5 kV of the long-rod & station post range (≤ 800 kV across the category, √ scale).
Specifications
Main
| Product type | Composite (silicone) long-rod insulator |
| Family | Siemens Energy 3FL silicone long-rod insulators — 3FL2 is the 70 kN distribution class (family SML classes span 70 – 630 kN) |
| Application | Suspension and tension on overhead lines, distribution power systems up to 72 kV |
| Housing | One-piece HTV silicone rubber, one-shot direct-injection molded onto the core rod |
| Hydrophobicity | HTV silicone rubber with hydrophobicity transfer mechanism for highest pollution performance |
Electrical
| Highest voltage for equipment (Um) | 12.0 – 72.5 kV (four housing lengths) |
| Typical nominal system voltages (Un) | 10 – 72 kV (10/11/12, 15/20/22/24, 30/33/35/36, 60/66/69/72 kV) |
| Lightning impulse withstand voltage (1.2/50 µs, dry) | 158 – 400 kV min, by length variant |
| Power-frequency withstand voltage (50 Hz, 1 min, wet) | 73 – 200 kV min, by length variant |
| Creepage distance | 426 – 2,321 mm — long creepage class, > 31 mm/kV |
| Arcing distance | 214 – 660 mm |
Mechanical & dimensions
| Specified mechanical load (SML) | Up to 70 kN |
| Housing length | 178 – 628 mm |
| Section length (with socket and ball 16) | 331 – 781 mm across the catalog variants; length increments 52 mm |
| Weight (with socket and ball) | 1.6 – 3.6 kg |
| Core | Boron-free ECR glass FRP rod — hydrolysis- and acid-resistant, brittle-fracture resistant |
| End-fitting attachment | Hot-dip galvanized forged steel or ductile cast iron, attached by monitored circumferential crimping |
| Sealing | Triple point directly overmoulded and totally encapsulated in the HTV silicone housing (sealing system A, used up to 210 kN) |
Standards, fittings & accessories
| Design & type testing | IEC 61109, ANSI C29.11, ANSI C29.12, CSA C411.4-16 (latest versions) |
| End fittings (SML 70 kN) | Ball 16 / Socket 16A per IEC 60120; Clevis 13L / Tongue 13L per IEC 60471; Y-clevis 16 / Eye 17 per IEC 61466-1 |
| Connection lengths | 75 – 94 mm depending on end fitting (ball 75, socket 79, clevis 87, tongue 87, Y-clevis 94, eye 93 mm) |
| Corona rings | Not required at line voltages ≤ 170 kV — none needed across the 3FL2 voltage range |
| Interchangeability | 100 % exchangeable and compatible with existing insulators and line hardware of all types |
Options & variants
Section length and weight apply to the version with socket and ball end fittings size 16 per IEC 60120; for other end fittings, add the housing length and both connection lengths. LIWL = lightning impulse withstand level (1.2/50 µs, dry); PFWL = power-frequency withstand level (50 Hz, 1 min, wet). Source: Siemens Power Engineering Guide Ed. 7.1, §4.10, p. 251.
| Um (kV) | Typical Un (kV) | LIWL min, dry (kV) | PFWL min, wet (kV) | Arcing distance (mm) | Creepage distance (mm) | Housing length (mm) | Section length (mm) | Catalog number | Weight (kg) |
|---|---|---|---|---|---|---|---|---|---|
| 12.0 | 10, 11, 12 | 158 | 73 | 214 | 426 | 178 | 331 | 3FL2 018-4SB11-1XX1 | 1.6 |
| 24.0 | 15, 20, 22, 24 | 216 | 89 | 300 | 805 | 268 | 421 | 3FL2 027-4SB11-1XX1 | 2.0 |
| 36.0 | 30, 33, 35, 36 | 243 | 111 | 390 | 1,184 | 358 | 511 | 3FL2 036-4SB11-1XX1 | 2.4 |
| 72.5 | 60, 66, 69, 72 | 400 | 200 | 660 | 2,321 | 628 | 781 | 3FL2 063-4SB11-1XX1 | 3.6 |
Documents & downloads
Flyer 3FL long rod insulators — Composite technology up to 800 kV (Siemens Energy, 2021)
Product guide Power Engineering Guide Ed. 7.1 — Ch. 4 Products and Devices, §4.10 Silicone Long Rod Insulators (3FL2 technical data, p. 251)
Brochure Our portfolio of surge arresters & composite insulators (Siemens Energy, 2021)
Also covered in the technical library
Flyer 3FL Long Rod Insulators — Composite Technology up to 800 kV
Catalog 3FL Silicone Long Rod Insulators for Overhead Power Lines
Brochure Our portfolio of surge arresters & composite insulators — Siemens Energy
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