Indoor Fiber Optic Cable
Indoor fiber optic cable is selected on two questions before anything else: how the cable behaves in a fire, and how easily it terminates at the panel. The Heizka indoor range answers both with a tight-buffered, all-dielectric design jacketed in low smoke zero halogen compound. It is intended for backbone and horizontal fiber inside the building envelope — riser shafts, equipment rooms, data halls and floor distribution.
Jacket Behavior and Why LSZH Is Specified
The Heizka indoor series is published with an LSZH jacket. Low smoke zero halogen compounds are formulated to emit little smoke and no halogenated gas when burned, which matters in enclosed occupied spaces where smoke obscuration and corrosive combustion products threaten both egress and adjacent electronic equipment. This is a materials property of the jacket, distinct from the fire-test listings a local code may require, so confirm the listing your authority having jurisdiction expects for the specific pathway before you release the specification. Where a project calls out a particular listing rather than a jacket material, ask us to confirm what is available against that requirement.
Tight Buffer Construction and Field Termination
The cable uses tight-buffered fiber, which is easy to strip. That is the practical difference from outdoor loose-tube cable: the buffer sits directly on the coating, so a technician can strip back and terminate onto connectors or splice onto pigtails at the panel without a breakout kit or fan-out assembly. Aramid yarn carries the tensile load during the pull. The structure is fully dielectric, with no metallic element, so the cable introduces no bonding or grounding obligation and is not affected by electromagnetic influence from nearby power runs — a real advantage in congested risers shared with electrical services.
The construction is described as light in weight and highly flexible, with a small bending radius. In practice this is what makes long vertical riser pulls and tight cabinet dressing manageable with a small crew.
Fiber Grades and Model Codes
| Model | Fiber grade | Typical use |
|---|---|---|
| HEFITNXX0LZ | OS2 singlemode | Building backbone, riser, long horizontal reaches |
| HEFITNXX2LZ | OM2 multimode | Legacy multimode extensions and equipment rooms |
| HEFITNXX3LZ | OM3 multimode | Laser-optimized multimode data hall links |
| HEFITNXX4LZ | OM4 multimode | Higher-reach multimode links inside the data center |
The XX field is the core count, confirmed at order. All four variants share the same tight-buffered, aramid-reinforced, all-dielectric LSZH construction, so a mixed OS2 and OM4 building can be built on a single cable design with a single installation method.
Standards Referenced
The indoor series is built against ISO/IEC 11801 for generic customer premises cabling, ITU-T G.651, G.652 and G.657 for the fiber itself, and IEC 60793-1, 60793-2, 60794-1 and 60794-3 for fiber and cable test methods. G.657 is the bend-insensitive singlemode recommendation, which is the relevant one when a riser or cabinet route forces tighter radii than a conventional G.652 fiber tolerates.
Frequently Asked Questions
Can this cable run in a plenum space?
The published jacket specification is LSZH. Whether that satisfies a plenum requirement depends on the code in force at your site and the fire-test listing it calls for, and we do not publish a plenum listing for this series. Send us the specification clause and we will confirm what is available.
Do I terminate directly onto connectors or splice onto pigtails?
Both work. The tight buffer strips cleanly for direct termination, and the Fiber Optic Accessories range includes patch panels with an integrated splice tray if you prefer to fusion splice onto factory-terminated pigtails inside the enclosure — usually the lower-loss and more repeatable option on a commissioned link.
Is there any grounding requirement?
No. The structure is all-dielectric with no metallic strength member or armor, so there is no bonding or grounding obligation and no shield continuity to maintain across the pathway.
How does this differ from the outdoor cable if the run only crosses a courtyard?
The indoor cable has no published water blocking or UV resistance. Any run leaving the building envelope, even briefly, should use Outdoor Fiber Optic Cable, which is water-blocked and jacketed in UV-resistant polyethylene.
Send us your core counts, grades and run schedule and we will return model codes and a quote. Start at contact us, see the full optical range under Heizka Fiber Cable, plan the pathway with Fibre Optic Raceway & Fiber Tray, or pair the job with Heizka copper cable.
