Fiber Infrastructure
What I found during the site review
I was at a job-site recently where fiber infrastructure was designed to be sent through conduits in a stairwell of the building; up-linking a number of network switches for a control system network. Each of these switches was in a wall mounted equipment rack in engineering rooms just off the stairwell every 15 floors all the way from the basement to the roof mechanical room. The electricians were tasked with running 1/2” conduit and 6 strand OM4 fiber between each location and followed up with LC terminations. What I found during review of the system is that the fiber had no protection once it came out of the conduit. The designers of the system had simply intended the fiber to directly connect to the network switch straight from the fiber.
This was problematic for two main reasons.
First, the fiber is directly connected from the trunk line to the network switch. If the fiber breaks for any reason, maintenance would have to call someone out to re-terminate the fiber. This would be a somewhat expensive call and it would require waiting for someone qualified to make an appointment to come to site.
Second, the network switch was mounted in the rack all the way on the front rails. This means that if anyone accidentally walked too close to the switch they could easily break the unprotected fiber.
Properly installing fiber infrastructure in an installed environment
The fiber trunk should have been designed to be terminated in a fiber tray. Securing the fibers in a fiber tray protects them as they exit the trunk line. Then jumper cables should have been used to connect the trunk line from the fiber tray to the network switch. This way, if the jumper is damaged, the maintenance team can simply replace the fiber with a spare.
This type of design reduces the potential for down time from a broken fiber and reduces the cost of maintenance. What could have been upwards of $1000 for a technician to come terminate a fiber has been reduced to a $15 patch cord purchase. This will also increase the longevity of the infrastructure which can be transitioned over time as the building’s needs change.
A pair of rack ear extenders was also installed to recess the network switch and fiber panel. I wanted to reduce the chances of the fibers being broken if someone walked too close to the rack.