The total quota of indoor branch optical cables is calculated by determining the actual average cable length per branch and multiplying it by the number of distribution points, while accounting for floor height, horizontal distances, and termination tolerances.

Step 1: Determine Average Cable Length

For each branch, calculate the average cable length using the formula: Average Cable Length = (Distance to Farthest IDF + Distance to Nearest IDF) / 2 + 2 × Floor Height This accounts for both horizontal routing and vertical rise between floors .

Step 2: Adjust for Actual Installation

Multiply the average cable length by a factor (typically 1.1) to account for routing deviations and add a termination tolerance (usually 6 meters for optical cables) to get the Actual Average Cable Length: Actual Average Cable Length = Average Cable Length × 1.1 + Termination Tolerance .

Step 3: Calculate Total Cable Requirement

Multiply the actual average cable length by the total number of floor distribution points (IDFs) to determine the total optical cable required: Total Optical Cable Required = Total Number of IDFs × Actual Average Cable Length .

Step 4: Consider Cable Type and Core Requirements

Select the optical cable type based on project specifications (e.g., 6-core multimode is commonly used for indoor branches). Ensure the number of fiber cores meets the design requirements for the number of circuits or users .

Step 5: Verify Conduit Fill and Installation Feasibility

Use a fill ratio calculator to ensure the selected cables fit within the conduit or cable tray without exceeding recommended fill limits. This helps prevent mechanical stress and allows for future expansion .

Step 6: Apply Standards and Best Practices

Follow standards such as ITU-T L.103, which define indoor optical cable characteristics, installation methods, and testing requirements. Adjust calculations based on the specific environment, building layout, and manufacturer recommendations . By following these steps, you can accurately calculate the quota of indoor branch optical cables, ensuring sufficient length, proper installation, and compliance with industry standards.