How to find OFC fault location?

How to find OFC fault location : The issue always arises in front of the person working on the OFC network, how to find the fault location of the OFC? OFC fault location becomes a headache when the partial cut of the OFC occurs. The OFC cut is usually caused by construction in the area, in the same way, some people also cut the OFC intentionally. In this article, I would like to discuss on this issue how to find out the OFC fault location.

To find the fault location of the OFC we have to do careful measurement technique with the OTDR. If it is already known in which area the construction work is going on the OFC route, then without the help of OTDR, the fault location can also be trace out. I would like to tell you that 40% OFC cut is caused by digging or construction.

Simple ways to  find the OFC fault location

We all know that OTDR is an invaluable tool for find the fault location of OFC. Accurate OFC fault location depends on OTDR traces obtained by site engineer and its accompanying careful measurement technique complete and accurate system (cable) documentation.

While the whole course often taught in place of mistake, following some recommendations the process below should be made more accurate and efficient sometimes it is needed.

Optical Fiber Cable breaks can be partial or complete cut. I have already mentioned above that most common cause of OFC breaks is digging or construction in the area, approx. over 40 % of all breaks are happen due to digging.

If the construction work is going on the area, the fault location does not need to be extremely precise as the damage can usually be easily located once one is in the vicinity.

But OTDR play a very important role and save a great deal of time and money when  other types of OFC breaks occurs like ballistic (from hunting weapons) or rodent damage.

When a cable is damaged the resulting break may be excessive reflective or non-reflective. It is very easy to determine an exact distance for a reflective event. Therefore, sometimes it is helpful to measure many broken fiber until a reflective break is found.

If the break is non-reflective, it is usually best to let the OTDR software determine the distance of events using automated analysis. It may be wrong to place a marker or cursor visually.

How to operate OTDR for find the fault

OFC network site engineers or technicians calibrate the OTDR to display the distance in the cable distance using an effective refractive index. This is important, while OTDR can cover a distance of 5 meters 10,000, the cable's helix factor will contribute to the 600-meter inaccuracy over a period of 10,000 meters.

Also an alternative way to find out the actual distance from the optical distance is to measure the break from both endpoints, and determination of break position relative to total span length. This ratio of optical distance to break the total optical length of the span will be proportional to the distance of the sheath to the brake.

It is important to remember at any location that the cable slack/loop/coil of OFC is also stored in the intermediate handhole, manhole or pole. If the OTDR reads 1600 meters to the OFC break but there are 200 meters of slack/coil of OFC stored at an intermediate handhole, manhole or pole, then the distance to the break will be similarly shorter.

It is important to remember that the sag distance in the aerial plant will be different at some distance from the pole. After the brake location is determined, it should be correlated with a cable sequential notation. Then, when digging the cable or examining the aerial plant with binoculars, the correct section of OFC can be quickly confirmed.

Remember it is always better to find out the distance of OFC fault location from the last event whose physical location is known on the OTDR signature using the cursors. In this method, the lowest possible measurement is performed on the OTDR reducing the OTDR contribution to measure inaccuracy.

During the initial cable documentation, take advantage of some of the OTDR features that allow adding notes to events or files. Geographic or GPS data can be entered here which will be very useful during fault location. I thing that there is no substitute for complete, detailed, accurate cable documentation records during fault.

Last Word

Friends, this article has been written to facilitate engineers and technicians working on OFC network. Friends, this article has been written to facilitate engineers and technicians working on OFC network. Some friends working on the site are very nervous due to the OFC cut and they do not understand where to start searching the fault location. How you like this article " How to find OFC fault location? " I hope that this is so much beneficial for such friends, take benefit of it yourself and participate to others to become a helping partners.