3.4.7 Student Book © 2004 Propane Education & Research Council Page 1

3.4.7Examining Bulk PlantElectrical Systems

Prevention of gas ignition in transfer areas is partially accomplished by the installation of properly selected electrical equipment and wiring .

In this module you will learn to identify:

(1) Regulations that pertain to propane bulk plant electrical systems

(2) Basic considerations for bulk plant electrical systems

3.4.7 Student Book © 2004 Propane Education & Research Council Page 1

Code Requirements for Propane Bulk Plant Electrical Systems

NFPA 58

2001

3.7.2.1 Electrical equipment and wiring shall be of a type specified by, and installed in accordance with NFPA 70, National Electrical Code (NEC).

3.7.2.2 Fixed electrical equipment and wiring installed within classified areas specified in Table 3.7.2.2 shall comply with Table 3.7.2.2 and shall be installed in accordance with NFPA 70, National Electrical Code.

Article 500 of NFPA 70, provides definitions of Division 1, and Divisions 2 areas requiring special attention to electrical equipment and wiring

NFPA 58

2004

6.20.2

NFPA 70

3.4.7 Student Book © 2004 Propane Education & Research Council Pages 1 & 2

Basic Considerations for Bulk Plant Electrical Systems

1. When making modifications or changes to a bulk plant wiring system, always use a licensed electrician.

2. Electrical control switches and wiring must conform to NFPA 70 NEC. Class I, Group D, Division 1 or 2 Installations.

3. Pump and compressor switches must be readily available to the dispenser operator.

4. Electrical control switches for dispenser pumps are typically heavy-duty single pole/single throw switches, similar to light switches, and mounted in a Class I, Group D, Division 1 or 2 explosion proof fixture.

3.4.7 Student Book © 2004 Propane Education & Research Council Page 2

Basic Considerations for Bulk Plant Electrical Systems

Figure 1aReadily Accessible Pump Switch

Figure 1b.Explosion Proof Switch Fixture

3.4.7 Student Book © 2004 Propane Education & Research Council Page 2

Basic Considerations for Bulk Plant Electrical Systems

5. OSHA requires that all electrical controls for equipment must be clearly marked and/or color-coded to indicate the on and off (stop) positions. The color designated for the “off” or “stop” position is red.

6. Safety codes require an electrical emergency shut down be located more than 20 feet (but less than 100 feet) from the dispenser, and prominently labeled.

7. All electrical wiring in Division 1 or 2 areas must be installed in rigid conduit, Class I, Group D and in flexible sections.

8. A seal-off fixture (commonly referred to as an EYS or Electrical Wye Sealoff) filled with a suitable putty must be installed between the dispenser area and the main electrical supply.

3.4.7 Student Book © 2004 Propane Education & Research Council Pages 2 & 3

Basic Considerations for Bulk Plant Electrical Systems

Figure 2. Class I, Group D Wiring Conduit,

Flex Section and Fixtures

Figure 3. Seal-off Fixtures to Prevent Propane Vapor from Entering Open Wiring

3.4.7 Student Book © 2004 Propane Education & Research Council Page 3

Basic Considerations for Bulk Plant Electrical Systems

9. Large pumps and compressors require magnetic starters and a 3-phase power source.

10. Caps on all fixtures must always be in place and securely tightened. All electrical wiring in Division 1 or 2 areas must be installed in rigid conduit, Class I, Group D and in flexible sections.

11. All fixture bolts must be in place and securely tightened.

12. Never paint over a plate or label.

13. KEEP ELECTRICAL SYSTEMS “UP TO CODE”.

3.4.7 Student Book © 2004 Propane Education & Research Council Pages 4 & 5

Time to See If You Got the Key Points of This Module…

• Complete the Review on page 4.

• See if you are ready for the Certification Exam by checking off the performance criteria on page 5.