Duct vs Direct Buried vs ADSS vs Fig-8: Which Fibre Cable Do You Need?
Duct, direct buried, ADSS and Figure-8 cables can all carry the same single-mode G.652.D fibre. What changes is how the cable protects that fibre on your route. Pick the wrong construction and the cable may sag between poles, get chewed by rodents or crushed in the soil. This guide compares the four main outdoor cable types we stock, using the figures from our datasheets.
The short answer
- Cable goes inside an HDPE pipe or duct: choose Duct Type (or Micro Duct for micro-duct networks).
- Cable goes straight into a trench: choose Direct Buried.
- Cable hangs on poles near power lines: choose ADSS (single jacket or double jacket).
- Cable hangs on poles on a normal telecom route: choose Aerial Fig-8.
Side-by-side comparison
| Cable | Installed | Metal | Tensile |
|---|---|---|---|
| Duct | Ducts, pipes | None | 3000 N |
| Direct Buried | In soil | Steel tape | 3000 N |
| ADSS | Poles | None | 5000 N |
| Fig-8 | Poles | Steel messenger | 3000 N |
Fibre counts in store: Duct and Direct Buried 2F – 144F, ADSS 4F – 96F, Fig-8 2F – 96F.
All four have a crush resistance of 2500 N/100 mm and are sold on 4 km reels. Armour: duct is all non-metallic with an FRP centre; direct buried uses corrugated ECCS steel tape; ADSS uses aramid yarn; Fig-8 has a 7-wire galvanised steel messenger.
All four use Corning SMF-28e+ G.652.D fibre with cabled attenuation of ≤ 0.35 dB/km at 1310 nm and ≤ 0.21 dB/km at 1550 nm, and a temperature range of −20 °C to +70 °C. The optical performance is the same; the difference is mechanical.
1. Duct cable
Duct cable is a non-metallic, dry-core loose-tube cable with an FRP central strength member and an MDPE/HDPE sheath. The pipe does the protecting, so the cable stays light, small and easy to pull over long distances. Because it has no metal, it can be laid close to power cables.
It is available with a Standard or LSZH sheath, from 2F to 144F. See Single Mode G.652.D Duct Type Optical Fiber Cable. For blown micro-duct networks, see Micro Duct (12F – 144F).
Do not use it for: burial without a pipe, or hanging between poles.
2. Direct buried cable
Direct buried cable adds a PE inner sheath, flooding compound and a corrugated ECCS steel tape armour under a robust outer jacket. The armour resists crushing, stones and rodent attack in the trench.
Choose the sheath on the product page: 1mm/2mm, 2mm/3mm + Aramid, LSZH 1mm/2mm, or Steel Wire Armoured (PE/SWA/PVC, 4F, 8F and 48F). See Direct Buried Optical Fiber Cable. For extra protection, see Triple Jacket Double Armoured; where you need rodent protection without metal, see Anti-Rodent Non-Metallic Direct Buried.
Keep in mind: steel armour is metal. Near high-voltage lines, choose a non-metallic cable instead.
3. ADSS cable
ADSS means All-Dielectric Self-Supporting. Aramid yarn carries the load, there is no metal at all, and the round profile reduces wind and ice loading. That makes it the normal choice on electricity poles and lightning-prone routes. It has the highest tensile rating of the four: 5000 N.
- ADSS Single Jacket: aramid layer under one PE jacket, 4F – 96F.
- ADSS Double Jacket: adds a PE inner sheath for tougher routes, 8F – 48F.
Important: span length decides the right ADSS cable. Tell us your typical and longest pole spacing before you order.
4. Figure-8 cable
Fig-8 cable joins the fibre unit and a 7-wire galvanised steel messenger in one jacket. The messenger takes the entire tensile load, so installation is a quick, one-step job and the fibres are protected from tension. It is an economical choice for telecom pole routes away from high-voltage lines.
See Aerial Fig-8 Optical Fiber Cable (2F – 96F). For extra protection on the fibre unit, see Armoured Fig-8 Aerial (8F).
What about drop and CLT cables?
For the last connection to a home or office, use a drop cable: Round Drop, Flat Drop or G.657 FTTH Drop. For small, armoured runs, use CLT Type. These come on 1 km or 2 km reels; enquire on WhatsApp for prices. Read more in our guide on choosing the right fibre optic cable.
Ordering
Duct, Direct Buried, ADSS and Fig-8 cables are sold by the 4 km reel. Choose the sheath and fibre count on the product page and add to cart. Each product page has a downloadable datasheet.
Need help choosing?
Send us your route type, length, fibre count and (for aerial routes) pole spacing, and we will recommend a cable. For prices, message us on WhatsApp +92 313 7776766, and you can browse all optical fibre cables. Delivery is free across Pakistan in 5–7 working days.
Enquiries: WhatsApp +92 313 7776766 or email info@litech.com.pk.
