ServerNet Cluster 6780 Planning and Installation Guide (G06.29+, H06.06+, J06.03+)

ServerNet Cluster Hardware Description

ServerNet Cluster 6780 Planning and Installation Guide—527301-008

2-27

Electric Code Regulations for Fiber-Optic Cables

Plenum-rated

Plenum-rated cables are required by some building codes in air plenums to protect

other areas in a building from the transportation of noxious fumes if a fire were to start

or spread through an air plenum. The plenum is the air-handling space between walls,

under structural floors, and above drop ceilings. The fire-resistant and low-smoke

characteristics of a plenum-rated cable allow it to be routed in a plenum area without

being enclosed in a conduit.

Because the plenum-rated cables are ruggedized and have a larger diameter than the

riser-rated cables, a 24-inch breakout is required to allow routing in the cable-

management assembly.

Riser-rated

Riser-rated cables can be used where plenum-rated cables are not required. A riser is

an area that passes between floors. It is normally a vertical shaft or space.

Fiber

Two types of fiber are supported for ServerNet clusters using 6780 switches.

Multimode fiber (MMF)

Multimode fiber is optical fiber designed to carry multiple light rays or modes

concurrently, each at a slightly different reflection angle within the optical fiber core.

Because the modes tend to disperse over longer lengths, multimode fiber transmission

is used for relatively short distances. Multimode fiber has a larger core than single-

mode fiber. The core diameter can be from 50 to 100 microns.

Single-mode fiber (SMF)

Single-mode fiber can be used for high-speed long-distance signal transmission. It

provides greater bandwidth than multimode. SMF is an optical fiber designed for the

transmission of a single ray or mode of light as a carrier. SMF supports only one mode

of light propagation above the cutoff wavelength. SMF has a much smaller core

diameter than multimode fiber. The typical diameter is 8 to 9 microns. The narrow core

allows light to enter only at a single angle.

WARNING. You are required to comply with the National Electric Code (NEC) Article 725 for

installations in the United States and with any local regulations for fiber-optic cables. Neither

the plenum-rated cables nor riser-rated cables are designed to be used in conduits.