FTTH Access
FTTH Drop Cable Guide: Structure, Types, and How to Choose for Last-Mile Drops
An FTTH drop cable is the last cable in a fiber network — the run from the distribution point (a splitter closure, pole, or building terminal) to the subscriber's premises. It carries one to a few fibers, and it is built to be cheap, fast to install, and tolerant of the tight bends and physical abuse of the last hundred metres. The choice comes down to one question: is this an indoor run, or an aerial span? Indoor drops are small flat cables; aerial drops add a self-supporting messenger to carry their own weight between poles. This guide covers the three drop-cable types, their real specifications, and how to pick.
Key takeaways
- Indoor vs aerial is the first split. Flat indoor drop for in-building/short runs; self-supporting (messengered) drop for pole-to-premises spans.
- Self-support comes in two flavours: an all-dielectric flat drop (GJYXFCH — thunder-proof, no metal) and a steel-messenger round drop (GYTC8H — higher tensile for longer spans).
- Near power lines, the all-dielectric self-support drop is the right call — it carries its own weight and has no metal to induce current or attract a strike.
- Drop cables bend tight — a static bend radius of 15× the cable dimension suits routing around door frames and along skirting.
- Fiber count is low — typically 1 to 4 fibers; the self-support flat drop uses bend-insensitive single-mode (G.657A).
The three FTTH drop cable types
DYS builds three drop constructions, and they map cleanly to where the cable runs. Figures below are published DYS specifications:
Type | Form factor | Dimensions | Tensile (short / long) | Messenger | Where it runs |
|---|---|---|---|---|---|
GJXFH | Flat | 2.0 × 3.0 mm | 200 N / 100 N | None (dielectric strength members) | Indoor / short drops |
GJYXFCH | Flat, self-supporting | 2.0 × 6.2 mm | 600 N / 300 N | Dielectric (all-dielectric) | Aerial, incl. near power lines |
GYTC8H | Round, self-supporting | 3.5 × 6.5 mm (1F) | 1200 N / 600 N | Steel wire rope | Aerial, longer spans |
All three carry 1–4 fibers, run −20 to +60 °C, and share a bend radius of 20× the cable dimension dynamic / 15× static. The pattern to read is the tensile column: the flat indoor GJXFH is rated 200 N short-term because it is not meant to hang; the two self-supporting types climb to 600 N and 1200 N precisely because a messenger is carrying the span. That messenger is also why the self-support cables are physically larger (the 6.2 mm and 6.5 mm dimensions include it).
Indoor drop: flat and small
The GJXFH flat drop is the workhorse of in-building and short-reach FTTH. At 2.0 × 3.0 mm it is barely thicker than a shoelace, with a pair of non-metallic strength members flanking the fiber, so it strips easily for a fast field connector. Its 200 N / 100 N tensile rating is a pulling and handling figure, not a hanging figure — it is designed to be run along walls, through risers, and to a wall outlet, where nothing but the installer's pull ever loads it. Because its strength members are non-metallic, it is safe to bring indoors and terminate without grounding concerns.
The trap to avoid: GJXFH is not an aerial cable. Hang 30 metres of it between poles and its own weight plus wind will exceed the long-term 100 N rating and stress the fiber. For any span, step up to a self-supporting type.
Aerial drop: self-supporting, dielectric or steel
Aerial drops carry an integrated messenger that bears the span load so the fiber does not. DYS offers two, and the difference between them is the messenger material — which decides where each belongs:
- GJYXFCH — a flat self-supporting drop, 2.0 × 6.2 mm, tensile 600 N / 300 N, on bend-insensitive single-mode fiber (G.657A). Its strength member is dielectric — the cable is all-dielectric and rated thunder-proof, anti-rodent and waterproof. Its short-term crush rating is 2200 N, well above the indoor cable, reflecting rougher aerial handling. Because it has no metal, it is the drop to use on spans that run near power lines or through high-lightning areas: it self-supports and has nothing to induce current or attract a strike.
- GYTC8H — a round self-supporting drop, 3.5 × 6.5 mm at 1 fibre (5.0 × 8.0 mm for 2–4 fibres), tensile 1200 N / 600 N, built with 900 µm tight-buffered fiber and a steel wire rope integrated into an 8-shaped ("figure-8") LSZH sheath. The steel messenger doubles the tensile rating for longer or more exposed spans — but it is metallic, so it is not the choice near power lines.
So the aerial decision is not just "how long is the span" but "is there a lightning or power-line risk?" — GJYXFCH (all-dielectric) for that risk, GYTC8H (steel, higher tensile) for the longest ordinary spans. For all-dielectric outdoor backbone cable beyond the drop, see the GYFTY all-dielectric guide.
How to choose a drop cable
- Indoor or aerial? Indoor/short and pulled, not hung → GJXFH. Spanning between poles or to a building → a self-supporting type.
- Near power lines or high lightning? → GJYXFCH — it self-supports and is all-dielectric, so there is no metal to induce current or attract a strike.
- Longest or most exposed ordinary spans? → GYTC8H, whose steel messenger gives the highest tensile (1200 N) — away from power lines.
- Fiber count and grade? 1–4 fibers; the self-support flat drop is bend-insensitive single-mode (G.657A).
- Termination? Flat drops strip fast for field connectors; confirm the connector and closure match the cable profile.
As a quick selection matrix:
Route | Span / load | Near power lines? | Cable |
|---|---|---|---|
Indoor / in-building | Pulled, not hung | — | GJXFH (flat, 200 N) |
Aerial | Typical pole-to-premises | No | GJYXFCH or GYTC8H |
Aerial | Any span | Yes | GJYXFCH (all-dielectric, 600 N) |
Aerial | Longest / most exposed | No | GYTC8H (steel messenger, 1200 N) |
The drop cable is the field-facing end of the network the splitter feeds — see the PLC splitter guide for what sits upstream in the ODN, and the FTTH deployment guides for the full access-network picture. Product details are on the DYS FTTH drop cable range.
Frequently asked questions
What is an FTTH drop cable?
It is the final cable in a fiber-to-the-home network — the run from a distribution point (splitter closure, pole, or building terminal) to the subscriber. It carries 1–4 fibers and is built to be low-cost, easy to install, and tolerant of tight bends and rough handling in the last hundred metres.
What is the difference between a flat and a self-supporting drop cable?
A flat drop (e.g. GJXFH, 2.0 × 3.0 mm) is a small cable meant to be pulled and routed, not hung — tensile around 200 N. A self-supporting drop adds a messenger to carry its own weight across an aerial span, raising tensile to 600–1200 N. DYS offers a flat all-dielectric self-support drop (GJYXFCH) and a round steel-messenger one (GYTC8H).
Can I use an indoor drop cable for an aerial span?
No. An indoor flat drop like GJXFH has a long-term tensile rating around 100 N — enough for pulling and wall routing, but not for hanging between poles, where its own weight and wind will overload it and stress the fiber. Use a self-supporting drop (GJYXFCH or GYTC8H) for any aerial span.
Which drop cable should I use near power lines?
GJYXFCH. It is a self-supporting flat drop with a dielectric strength member — all-dielectric and rated thunder-proof — so it carries its own weight across a span while having no metal to induce current or attract a lightning strike. The steel-messenger GYTC8H, by contrast, should be kept away from power lines because its wire rope is metallic.
How many fibers are in a drop cable, and what grade?
Typically 1 to 4. Most FTTH drops are single-fiber; 2–4 fiber drops serve small business or multi-service premises. The self-supporting flat drop (GJYXFCH) uses bend-insensitive single-mode fiber (G.657A), which tolerates the tight bends of drop routing.
Are FTTH drop cables bend-sensitive?
They are built to tolerate tight bends — a static bend radius of about 15× the cable dimension, which for a 2–3 mm drop is very small — and the flat self-support drop uses bend-insensitive G.657A fiber for exactly this reason. Still respect the rated radius; over-tight bends add loss and, over time, risk the fiber.