Cable Selection
GYFTY All-Dielectric Non-Metallic Aerial Fiber Optic Cable
GYFTY is an all-dielectric, non-metallic loose-tube outdoor cable — it contains no metal at all. A central fiberglass (FRP) strength member replaces the steel wire used in conventional cable, so the cable neither conducts electricity nor attracts lightning. That makes it the standard choice for aerial and duct runs near power lines, in high-lightning areas, and anywhere strong electromagnetic interference would disturb a metallic cable. It carries 12 to 144 fibers, in a stranded loose-tube construction with a water-blocking system and a PE outer sheath.
Key takeaways
- All-dielectric = zero metal. FRP central strength member and non-metallic construction — no steel, no conduction, no lightning attraction.
- Built for electrically hostile routes: alongside power lines, in high-lightning zones, and in high-EMI environments where metallic cable is a liability.
- 12–144 fibers, Ø8.4–15.0 mm depending on count, in a stranded loose-tube design that keeps fibers stress-free under tension.
- Tensile 1500 N short-term / 600 N long-term across all fiber counts, rated −40 to +70 °C.
- Aerial and duct — the same cable serves lashed aerial spans (on a separate messenger) and duct installation.
What "all-dielectric" means, and why it matters
Most outdoor cable uses steel — a steel central wire for strength, and often steel tape armor for crush and rodent resistance. Steel is cheap and strong, but it is metal, and metal is a problem in two situations: near high-voltage power lines, where a metallic cable can pick up dangerous induced voltage, and in high-lightning areas, where metal is exactly what a strike looks for.
GYFTY removes the metal entirely. Its strength comes from a fiberglass-reinforced plastic (FRP) central member instead of steel wire, and there is no metallic armor. The result is a cable that:
- Does not conduct — no induced current from adjacent power lines, and no path for fault current.
- Does not attract lightning — nothing metallic to draw or carry a strike.
- Is immune to electromagnetic interference — the FRP member and non-metallic build give it excellent anti-EMI behavior, so it can run through electrically noisy environments a metallic cable would not tolerate.
That is why GYFTY's stated applications are aerial and duct runs in "high electromagnetic interfering and frequently lightning areas" — the routes where an all-dielectric cable is not a preference but a requirement.
GYFTY specifications by fiber count
GYFTY is published in five fiber-count bands. As the count rises, more loose tubes strand around the central member and the finished cable grows — the diameter and weight climb, while the mechanical ratings stay constant:
Fiber count | Cable OD | Weight | Tensile (short / long) | Crush per 100 mm (short / long) |
|---|---|---|---|---|
12–48 | Ø8.4 ±0.2 mm | 88 kg/km | 1500 N / 600 N | 1000 N / 300 N |
60–72 | Ø10.5 ±0.5 mm | 102 kg/km | 1500 N / 600 N | 1000 N / 300 N |
74–96 | Ø12.0 ±0.5 mm | 130 kg/km | 1500 N / 600 N | 1000 N / 300 N |
98–120 | Ø13.5 ±0.5 mm | 156 kg/km | 1500 N / 600 N | 1000 N / 300 N |
122–144 | Ø15.0 ±0.5 mm | 180 kg/km | 1500 N / 600 N | 1000 N / 300 N |
GYFTY is supplied in both single-mode and multimode versions — the cable construction is the same; the fiber inside is chosen to suit the link. Bending radius is 20× the cable diameter (dynamic) / 15× (static), and the working temperature range is −40 to +70 °C. Note the tightest-tolerance band: at 12–48 fibers the diameter is held to ±0.2 mm, tighter than the ±0.5 mm on the larger counts — worth confirming against duct fill and cable-gland sizing on tight installs. Standard reel length is 2 or 3 km, and other lengths are available.
Loose-tube stranding: why the construction matters
GYFTY is a stranded loose-tube cable — the fibers sit loosely inside gel-filled or dry tubes that are then stranded helically around the central FRP member, rather than being bonded tightly to the cable body. That helical lay gives the fibers a small amount of excess length: when the cable is pulled or sags under its own weight, the tube takes the strain and the fiber inside simply shifts within it, staying mechanically stress-free.
This is the property that makes GYFTY suitable for aerial spans and long duct pulls. The 1500 N short-term tensile rating is what the cable survives during installation (pulling tension); the 600 N long-term rating is what it can bear continuously in service (self-weight plus wind and ice load on an aerial span). Designing an aerial run means keeping the sustained load under that long-term figure — the short-term number is a pulling limit, not a hang-forever limit. The cable selection guides cover how to read tensile and crush ratings against a real installation.
Where GYFTY fits — and where it does not
All-dielectric is the right call on specific routes and the wrong call on others. Matching the construction to the route is the whole point of an outdoor cable line:
Route condition | Cable to use | Why |
|---|---|---|
Aerial (lashed) / duct near power lines, high lightning | GYFTY (all-dielectric) | No metal to induce current or draw a strike |
High EMI environment | GYFTY | Non-metallic build is EMI-immune |
Duct / aerial, rodent-prone, no HV nearby | GYTS (steel-tape armored) | Steel armor for crush and rodent protection |
Direct burial, harsh ground | GYTA53 (double-jacket, double-armored) | Moisture and rodent resistance for buried runs |
The short version: choose all-dielectric GYFTY when the electrical environment is the threat (power lines, lightning, EMI); choose an armored steel construction when the physical environment is the threat (rodents, crush, direct burial) and there is no high-voltage concern. For the count-to-diameter figures across the outdoor range, see the fiber optic cable size chart; to browse the constructions, the DYS outdoor cable range.
Frequently asked questions
What does GYFTY stand for?
GYFTY is a Chinese national-standard cable type code: it designates an outdoor communication cable with a loose-tube stranded structure, a non-metallic (FRP) central strength member, and a polyethylene sheath — in short, an all-dielectric, non-armored outdoor cable. The letters encode the construction rather than being an English acronym.
What does "all-dielectric" mean?
It means the cable contains no metallic parts — no steel strength member and no metal armor. Strength comes from non-conductive fiberglass (FRP) instead. Because there is no metal, the cable does not conduct electricity, does not attract lightning, and is immune to electromagnetic interference, which is why all-dielectric cable is specified near power lines and in high-lightning areas.
How many fibers does GYFTY hold?
12 to 144 fibers, across five count bands. The cable diameter grows with the count — from Ø8.4 mm at 12–48 fibers to Ø15.0 mm at 122–144 — as more loose tubes are stranded around the central member.
What is the tensile strength of GYFTY cable?
1500 N short-term and 600 N long-term, the same across all fiber counts. The short-term figure is the maximum pulling tension during installation; the long-term figure is the sustained load the cable can bear in service, which is what governs aerial span design.
What is the difference between GYFTY and GYTS?
Both are stranded loose-tube outdoor cables, but GYFTY is all-dielectric (FRP strength member, no metal) while GYTS is steel-tape armored. Choose GYFTY where the electrical environment is the risk — power lines, lightning, EMI; choose GYTS where physical protection against crush and rodents matters and there is no high-voltage concern.
Can GYFTY be used for aerial installation?
Yes. GYFTY is rated for both aerial and duct installation. For aerial spans, the long-term tensile rating of 600 N is the figure to design against — the sustained load from the cable's own weight plus wind and ice must stay below it. For spans requiring an integrated messenger, a self-supporting construction is used instead.