The key differences
| Copper (Cat6 / Cat6a) | Fiber | |
|---|---|---|
| Maximum distance | 100 m (328 ft) per channel | Hundreds of meters (multimode) to kilometers (single-mode) |
| Carries power (PoE) | Yes | No |
| Electrical interference | Can be affected | Immune |
| Typical use | Desks, phones, cameras, access points | Closet-to-closet, floor-to-floor, building-to-building |
| Termination | Simple, quick | Specialized tools and testing |
Where copper belongs
Copper is the right choice for anything within 100 meters of a closet, and anything that needs power. Access points, cameras and desk phones all run on Power over Ethernet, which only copper can carry. The 100-meter limit is a channel: 90 meters of installed cable plus up to 10 meters of patch cords. See Cat6 vs Cat6a for which copper to install.
Where fiber belongs
- Between closets on the same floor when the run is long or you need 10 Gb/s and up.
- Between floors through the building riser, a common setup in Manhattan offices that span several floors.
- Between buildings, where copper would carry electrical risks and fiber has no distance problem.
- Near heavy electrical equipment, such as elevator machine rooms or large motors.
Single-mode vs multimode
Multimode fiber (OM3 and OM4, usually aqua jacket) is for shorter runs inside a building. At 10 Gb/s, OM3 reaches about 300 meters and OM4 about 400 meters. The optics are cheaper.
Single-mode fiber (usually yellow jacket) reaches kilometers and is what carriers use. Inside buildings it's increasingly chosen for risers and campus links because it supports future speeds over longer distances.
The fiber type and the optics on each end must match. Mixing them is one of the most common reasons a new fiber link doesn't come up.
NYC building notes
Running fiber between floors usually means the building's riser, which needs landlord approval, a certificate of insurance and often after-hours work. Start that paperwork early, especially for an office move.
Sources
- Category 6 cable: Cat6 and Cat6A specifications (Wikipedia)
- Multi-mode optical fiber: OM3 and OM4 reach (Wikipedia)
Technical figures checked against the sources above. Standards and product details change; confirm with the manufacturer for your equipment.
