External starters with the ballast (found in some older fluorescent preheated fixtures)(Figure 3-21). (Starters are rated by their wattage capacity. Make sure that you install the proper starter.) 
Figure 3-17. Box or channel casement
Figure 3-18. Ballast and lamp holder
Figure 3-19. Lid
Figure 3-20. Tube
Figure 3-21. External starters
The schematic layouts for fluorescent fixtures are basically the same. The preheated system uses a starter in conjunction with the ballast to get the tube glowing ( Figure 3-22).
Figure 3-22. Schematic layout for fluorescent fixtures
The instant-start fluorescent fixture does not have a starter. It has a special tube and a ballast which produce 400 to 1,000 volts. This type of tube is called a single-contact pin type because it has a single electrode pin on each end (Figure 3-23).
Figure 3-23. Instant-start fluorescent fixture
Rapid-start fluorescent fixtures have a ballast which works at lower voltages than other types. An externally grounded metal plate helps the tube start up ( Figure 3-24).
Figure 3-24. Rapid-start fluorescent fixture
Different-size tubes can have from 4 to 245 watts and can be from 6 to 96 inches long. Tubes can be straight, U-shaped, or round. Be careful when handling fluorescent tubes, since they are easily broken (Figure 3-25).
Figure 3-25. Tubes
Fluorescent tubes come in different colors. The color variation is determined by the type of gas contained in the tube. Table 3-1 explains this further.
Table 3-1. Fluorescent lighting colors and characteristics
Ballasts supply the proper voltage and limit the current supplied to the tube ( Figure 3-26).
Figure 3-26. Ballast
A single-tube fluorescent fixture is shown in Figure 3-27. This fixture will be a simple wiring job.
Figure 3-27. Single-tube fluorescent fixture
Two-tube fluorescent fixtures are the most common and are used for both two-tube and four-tube fixtures. To wire a four-tube fixture, 2 two-tube ballasts are used ( Figure 3-28).
Figure 3-28. Two-tube fluorescent fixture
Figure 3-29 shows a three-tube fluorescent fixture. Notice the difference in the amount of wires.
Figure 3-29. Three-tube fluorescent fixture
Types of ballasts differ with each manufacturer. Check each ballast to be sure that it has a wiring diagram on it (Figure 3-30).
Figure 3-30. Types of ballasts
The pin arrangement should always be checked for adaptability (Figure 3-31).
Figure 3-31. Pin arrangement
Troubleshooting fluorescent faults is performed by using common sense, knowledge of fluorescent fixtures, and a troubleshooting chart (Table 3-2).
Table 3-2. Troubleshooting chart for fluorescent lighting
The average life of fluorescent ballasts and tubes is 12 years or about 60,000 hours. Most ballasts are designed to operate at 90°C. A rise of 10°C can reduce a ballasts life by one half.
