1. PUMP STATION ELECTRICAL DESIGN
40 Years Lessons Learned
Maynard Wayne Robertson, PE, CEM
TAUD Technology Conference
Gatlinburg, TN March 13, 2013

2. Pump Station Design Requirements
Tennessee Dept. Environment & Conservation
Environmental Protection Agency
NFPA- 70- National Electrical Code
Tennessee Fire Marshall- Electrical Inspections
OSHA/TOSHA

3. TDEC Requirements General Design Requirements for Sewerage Works
Key Chapters for Pump Stations; 1, 2, 14
Chapter 2. Section 2.5 Pump Stations
Alarm System and totalizers on All stations
2.6.3 All wet well wiring to be Class l, Division l, per NEC
2.7.3 PS Capacity Greater Than MGD
Requires Flow Meters
Requires Back Up Power System

4. TDEC Requirements
Chapter Requires to comply with All OSHA Rules. Work place safety.
Chapter 2.7- Operability/ Reliability Do you need generator/backup power? Essentially EPA requirements.
Reliability Class 1, Class 2, Class 3.

5. TDEC
2.5 Septicity Controls. I guess something that smells BAD. Do not make it smell worse. Setting controls for minimum time in wet well.
Auto Pump Out (Timed pump start after low
level contact made, low cost to reduce odor )
Electric Power Systems
Chapter
Design Criteria for Sewerage Works

6. National Electrical Code
Latest Version NEC-2011
Next Version NEC-2014
Code revised on Three Year Cycle
Version adopted in Tennessee NEC-2008

7. NFPA CHAPTER 70 National Electric Code / 70E work place safety
NEC 2008 Used Statewide
*Exceptions In Some Cities NEC-2011
70E Work Place General Safety Requirements
Installation Of Equipment
Protection Of Electrical Equipment

8. NEC-2008 Organization Chapters: One thru Nine Articles Tables Appendix
Chapters: One Thru Four
Basic Wiring Requirements.
Apply to all Wiring Installations.
Chapters: Five thru Nine
Special Conditions

9. NEC Chapters Chapter 1 – General Chapter 2 – Wiring and Protection
Chapter 3- Wiring Methods and Materials
Chapter 4 – Equipment for General Use
Chapter 5 – Special Occupancies
Chapter 6 – Special Equipment
Chapter 7 – Special Conditions
Chapter 8 – Communications Systems(Stands alone)
Chapter 9 – Tables
Annex A thru H ; Informational Only

10. Key NEC Articles for Sewer Pump Stations
Articles: 200, 215, 220, 240, 250, 310, 312, Table , 400, 430, 445, 500 & 700. Note: Entire Code Applies Always!!

11. Tennessee State Fire Marshall
Requires Electrical Inspection of all New and Modified Electrical Installations.
Require Use of Listed Equipment- UL, etc.
Current Enforcement NEC
Authority Having Jurisdiction

12. EPA EPA-430-99-74-001 Operability and Reliability
Class 1 Standby Power nearly always required
Class 2 Standby Power maybe Required
Class 3 Normally not Required

13. Service Terms Service Service Entrance Metering Service Disconnect
Service Type
Overhead
Underground
Single or Three Phase
Available fault Current

14. NEC Voltage Low Voltage = Less Than 600 Volts Single Phase
Motors 5 HP or Less( 7.5 & 10.0 are manufactured)
Three Phase
120/240 Volt Delta Connected
120/208 Volt Wye Connected
277/480 Volt Wye connected

15. Electrical Service Entrance
Capacity for both pumps to operate
Service disconnect rated for service entrance and capacity to allow second motor to start without tripping
Service Equipment( Main Breaker and panel boards, etc.) rated for available fault current
Fault Currents can be high at PS as result of large transformer and short wire runs
Standard Interrupting capacity: 10,000, 22,000, 65,000amps
Grounding and Bonding
Adequate work space in front of electrical equipment
For outdoor locations shield panels from sun and heat

16. Wiring Methods NEC Article 250 Grounding and Bonding
Table Size of Equipment Ground Conductor
Grounded Conductor
Ground Wire
Lightning protection
Table /Table B(2)a, more than 3 conductors in raceway/conduit
Conductors Rated at 75C
Conductors Rated for Wet Location

17. Control Panels Correct NEMA Enclosure ( 3R, 4X, etc. )
Ventilation/Cooling
Drains
Labeled (UL, CSA)
Alarms
Control Transformer (Reduce line Noise)
Instrumentation (Runtime, Volts, Amps, Calibration)

18. Motor Starters
Manual
Across the Line starters( NEMA SIZE 0, 1, 2, etc.)
Part winding
Auto transformer
Soft Start
VFD (6 pulse more noise and 12 pulse less noise)
VFD noise may interfere with controls/SCADA

19. PHASE CONVERSION Single Phase Power to 3 Phase Power
Phase Conversion Using VFD
Size VFD Based On Single Phase Load Plus 15%
20Hp, 3P, 230V, FLA=54 Amp
Based on single phase = 100 Amp
Use 120 Amp VFD

20. Common WWPS Problems Corrosion, Corrosion, Corrosion!!!!
Electrical Junction Boxes in Wet Wells
Excessive Pumps starts/ Short run time
Unlisted Electrical Equipment (Inspector Rejects)
FAILURE TO DERATE CONDUCTORS in Conduit. (more than three)
Lack of Phase Loss Protection
Phase to Phase Voltage/excessive voltage difference.
Poor Electrical Grounding
No Isolation of sewer gas from control Panels thru use of junction boxes with double conduit seals. Complete failure less than 1 year.
Circuit Breakers too small, Result excessive heat in Panel.

21. Common WWPS Problems
NO Conduit Seals, Sewer Gas direct line to control Panel.
Pump Rotation
Wrong NEMA Class Enclosures
Low Equipment Electrical withstand Ratings.
VFD noise on Control circuits
No GFIC Receptacles
Generators/ transfer switches improperly wired/ Phase Reversed.

22. Checklist/Records Always use startup Checklist
Voltage, Line to Line, Line to Ground, Phase to Phase
Amperes
Discharge Head
Pumping Rate
Photos
Nameplate Data
Terminals Tight

23. WWPS Life Cycle Cost Initial Cost Installation Commissioning Cost
Maintenance and Repairs Cost
ENERGY COST 90 PERCENT OF TOTAL
High Efficiency Motors
High Efficiency Pumps

24. Generators
Correctly Sized to start second pump with all loads energized
Portable /Permanent
Transfer switches/ Manual or automatic
Fuels/ Diesel, Natural Gas, Propane, Gasoline.
Long Term maintenance cost

25. PUMP STATION ELECTRICAL DESIGN
40 Years Lessons Learned
Maynard Wayne Robertson, PE, CEM
TAUD Technology Conference
Gatlinburg, TN March 13, 2013