• Central Office power background topics covered in this class are basic electricity and basic telephony that provide a solid background for understanding Central Office power. The training course then covers
• The operation, maintenance and repair of AC power equipment
• DC power equipment
• DC power distribution
• Breakers and fuses
• Grounding protection
• Test equipment
• Central Office battery rundown test performed in the Maintenance Window.
• And much more

Lesson 1 - Basic Electrical Principles

A general knowledge of basic electricity is required to understand the operation and maintenance of Central Office power equipment. This lesson covers basic AC and DC electrical theory and related concepts necessary to form a fundamental understanding to build on.

Objectives: After completing this lesson the student will understand the terms and principle concepts of basic electricity related to Central Office power equipment.  The student will be able to define Voltage, Current and Resistance and how they are used with Ohms Law; describe AC and DC current; and calculate power and circuit loss in actual circuits.



Lesson 2 – Basic Telephony

Understanding basic telephone theory and practical application is needed to fully understand the use for DC power in the CO.  This lesson covers the concepts and real use of telephone equipment that is the very basis of all telecommunications.

Objectives:  After this lesson, the student will be able to describe the analog VF signal, cable pair characteristics and the effects of VF transmission on cable pairs.  The student will be able to identify sources of noise and methods of noise reduction.  The student will understand the MDF layout, and identify safety issues inside the Central Office.



Lesson 3 – General Central Office Power

Nearly all Central Office equipment requires DC power to operate; therefore, a solid basic understanding of the source and distribution of DC power is essential to understanding how all Central Office equipment works.  This lesson covers AC power, the conversion from AC to DC power, DC power distribution, and the use of fuses and breakers.

Objectives:  After completing this lesson, the student will be able to describe the different elements that make up the AC and DC power scheme in the Central Office.



Lesson 4 – AC Power Equipment in the Central Office

This lesson studies the power source for the entire CO: Commercial AC.  Areas covered in this lesson are:

•    Main AC Disconnect switch
•    AC surge arrestor
•    AC transfer switch
•    Standby Generator
•    AC sub-panels

Objectives:  After completing this lesson, the student will be able to describe the different elements that make up the AC Central Office power.



Lesson 5 – DC Power Equipment in the Central Office

This lesson studies the protection and distribution of DC power in the Central Office.  Areas covered in this lesson are:

•    Rectifiers; including settings and connections
•    Battery; including function, routine maintenance and testing
•    Main power board; including DC breaker, shunt, ammeter and A&B feeds
•    Power distribution and cabling; including sizing, length, connections and routing
•    Fuse and breaker panels
•    Equipment power feeds.

Objectives:  After completing this lesson, the student will be able to describe the different elements that make up the DC power distribution in the Central Office.


Lesson 6 – Central Office Battery Rundown Test (Optional)

This Optional lesson is a Maintenance Window activity that must be pre-arranged and scheduled by the local telephone company.  This exercise will take approximately 4 hours.

The only sure method of verifying the true reserve power of the Central Office battery is to perform a load test of the entire battery for an extended period of time.  The load test requires that the rectifiers AC Input breakers be turned off and the battery allowed to carry the office load for 1 to 4 hours until discharge data is sufficient to predict the battery reserve.

In this lesson, the student will perform a step-by-step Central Office battery rundown test and determine the real reserve of the battery.

Objectives:  After the student completes this lesson, they will know the step-by-step procedure for performing a Central Office battery rundown test and will be able to determine the real reserve time of the battery.



Lesson 7 – Central Office Grounding and Protection

Central Offices are required to have an effective bonding & grounding and protection arrangement installed for the protection of personnel and sensitive electronic equipment inside the Central Office building per the National Electrical Code.  This lesson studies the concepts and practical application of the Central Office grounding and protection system requirements, and the methods used to test the integrity of the grounding system.

Objectives:  After completing this lesson, the student will be able to describe the reasons for having a good Central Office grounding system, the function of the Master Ground Bar and the prescribed methods of testing the integrity of the Central Office grounding system.