Friday, July 8, 2016

Power Cables Must Be Selected According to the Actual Maximum Power Consumption When Junction Boxes Are Used

Power cables for the OptiX OSN 6800 system must be selected according to the actual maximum power consumption when junction boxes are used.

Product

Fault Type

Power Supply

Symptom

An OLA station in a network is configured with two subracks and two CRPC subracks. Due to an engineering survey error, only two 15 m long power cables with the core diameter 16 mm2 are provided as the active and standby external power cables. Four output power supplies, however, are required in field. Therefore, one more power cable or a junction box is required.
In addition, there are only two input terminals of 63 A circuit breakers in the telecommunications room of the customer.

Cause Analysis

The PDU on the OptiX OSN 6800 is divided into active and standby areas. Each area has two input power supplies and six output power supplies.
The mapping relationship of the input and output power supplies is as follows:
  • Input power supply 1: output power supplies 1, 2, and 3
  • Input power supply 2: output power supplies 4, 5, and 6
When more than three output power supplies are required, two input power supplies or junction boxes are required.
The configuration of the OLA station is simple and the maximum power consumption does not exceed 2400 W. In addition, -63 V power supply is used. Therefore, two 63 A circuit breakers can satisfy the power supply requirements. When power cables with the core diameter 16 mm2 are used, a junction box can be used to implement the two input power supplies under the following conditions:
  • The total power consumption is lower than 2500 W.
  • The distance between the power cable and the power distribution cabinet is shorter than 20 m.
  • The normal ambient temperature is lower than 40°C.
After an analysis of the field environment, it is determined that the power supply problem can be resolved by adding a junction box.

Procedure

  1. None.

Result

The problem is resolved.

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