Should Maintenance Be Performed on a Routine Basis?
It is commonly thought that, once a cable leak has been found and fixed, the cable will be safe from moisture. After a repair, there is a natural tendency to conclude that everything is okay and that maintenance can be ignored until more leaks are found on the cable. This couldn't be further from the truth.

Maintaining a reliable cable plant is something like maintaining a large building. Deterioration of the building must be taken seriously, especially the roof, which should be frequently repaired to ensure extended use. Several parts of the country experience long periods of dry weather where structures are not subjected to water damage. There's no problem for buildings (and cables) when it doesn't rain, but after extended periods of neglect, they both require constant attention to fend off the water problems when the storms come. Maintenance is best performed when the weather's dry.

Today, this type of routine maintenance is often called proactive maintenance. Many telephone companies are shifting toward a proactive approach to the outside plant in order to prevent subscriber calls, Public Utilities Commission (PUC) complaints, and even catastrophic failure. It's preventive medicine for the outside plant. Rather than treating the outcome of poor health (big leaks and low delivery pressure), a good diet and exercise program (changing out old cable/devices and performing maintenance on the problematic routes first) will keep future problems from occurring.

Are Cable Leaks Hard to Find? When looking for leaks, an entire cable cannot be held under water (like a tire tube) to look for bubbles at the point of damage. You have to devise another method. Pressure readings will tell you that a cable is losing air, but they don't tell you where. Because there is an inherent amount of air flow in pressurized cables, the best scheme is to follow the air flow to the leak. By setting up check points and using devices to measure the air flow, the leak can be quickly located without a foot-by-foot examination of the cable.

To use another analogy, let's say we're transporting money between two points (Checkpoints A and B). We would want to count the amount leaving Checkpoint A and confirm that it arrived at Checkpoint B. If the two amounts were not the same, this would indicate that we had a problem somewhere along the way between Checkpoint A and B. By counting the amount of air flow at two designated checkpoints on a cable route, we can quickly determine if there is a leak between them. If everything arrives at Checkpoint B, we're home free because there is no leak in that particular section.   (continued...)