power supplies for electric motor driven fire pumps

Download Power Supplies for Electric Motor Driven Fire Pumps

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Requirements and Application Information. Both NFPA-20 and Article 695 of NFPA-70 (NEC) are covered.


Electric Motor Drive Fire Pumps and Power Supplies

Fire Pump Power SuppliesApplicable Codes and Intent- by -James S. NasbyColumbia Engineering

Topics to be Covered Are:1 - Applicable Standards2 - Power Source(s) for Fire Pumps3 - Continuity of Power to a Fire Pump4 - Transformers in the Fire Pump Circuit5 - Power Wiring to a Fire Pump6 - Other Requirements7 - Rules of Thumb (For Reference Only)8 - Fault Current Considerations

Applicable StandardsNFPA 70, the NECArticle 695 -and-NFPA 20 Fire Pump Power SuppliesNFPA-20 - Chapter 9 - Performance & Acceptance Testing of Power SourcesNFPA-70 (NEC) Section 695 & etc. Installation of Electrical EquipmentNFPA-25 - Inspection, Testing, etc. - also -Local Codes - E.g. C.E.C. (Chicago Electrical Code)Insurance Company Requirements (IRI, FM & etc.)

NFPA 20 Standard for the Installation of Stationary Pumps for Fire ProtectionSeveral requirements of Article 695, including power sources, are extracted from NFPA 20** Note: The NEC TCC rejected updating extract text from NFPA-20-2007. Thus the 2008 NEC retained the wording from NFPA-20-2003. A task group is looking into this situation.

What is Covered by NEC Article 695Electrical power sourcesInterconnecting circuitsSwitching and control equipment dedicated to fire fire pump drivers. E.g.: Service Entrance Gear.695.1(A)

What Is Not Covered By Article 695System Performance -- NFPA-20 E.g. Fire Pump Controllers and Transfer Switches.Maintenance -- NFPA-25Acceptance testing -- NFPA-20Routine (Periodic) Testing -- NFPA-25Jockey pumps -- NEC Article 430Alarm Systems -- NFPA-72695.1(B)

How Is Article 695 Applied?Because it is located in Chapter 6, Article 695 applies to special equipment It amends the requirements of Chapters 1 - 4 in the NEC for fire pump installationsExample: Article 695 amends Articles 240 and 430Article 695 is NOT modified by Article 700 (Emergency Systems)90.3 & 695.2

What Is the Intent . . . of Article 695 -and- NFPA-20Fire Pump sources and components must be Reliable, and

Should the Fire Pump Be Called Upon to Function, It Is Considered SacrificialNFPA 20 and 695.3

2 - Power Source(s) for Electric Motor Drive Fire Pumps General Philosophy Permitted power source(s) Individual power sources(s) Multiple power sources Power source(s) performance Maximum Voltage Drops

General PhilosophyPower Sources for Electric Motor Driven Fire PumpsRequirements focus on the continuous uninterrupted operation of the fire pump. Electrical safety is considered a secondary objective. Fire pump equipment is considered sacrificial.As such, Equipment and Conductors may constitute a fire hazard.Protection of the premise and occupants of paramount importance.

Permitted Types of Power Sources for Electric Motor Driven Fire PumpsIndividual Power SourceUtility Service On-Site Power Production PlantMultiple (other) Power SourcesAbove twoStand-by Gen-setFeeder Sources(Campus like Complexes)695.3

Number of Reliable Electric Power Sources Required Power to be supplied by a (one) reliable sourceOr by at least two approved independent (other) sources.

-- however --

Where height of building is beyond pumping capacity of the fire department, an emergency or back-up power supply is mandatory.-and- Additional Chicago Requirements

A Reliable Electric Power Source . . .To consist of Electrical Service or Private Power Station - where -Infrequent disruption from environmental or man-made conditionsContains a separate service connection -or- connection to the supply side of the buildings service entrance disconnect means

Determination of reliability up to discretion of the AHJ (Authority Having Jurisdiction).

What Are Individual Power Source(s)?1. Separate Service, or 2. Tap Ahead of the Premise (Plant or Building) Service Equipment - or - 3. On-Site Power Production Facility (On-Site 24-7 Power Plant)695.3(A)

Separate Service as an Individual Power Source.Separate utility service dedicated to the fire pumpPermitted by Section 230.2Shall comply with all applicable rules of Chapters 1-4, including Article 250.

Each Individual Power SourceMust be Located

and Arranged to Minimize Possibility of Damage By Fire.

sufficiently remote 230.72(B)

And, both must have signs at both location. 230.2(E)

Separate Service From a Utility Normal ServiceFire Pump ServiceSufficientlyRemote


Power Supply ArrangementPower supply to pump is to be maintained when building normal power is disconnected.

Exception for feeder circuit serving as one source - disconnection of plant power to fire pumps permitted if alternate source is continually available

Tap Ahead of the Building ServiceEquipment requirements are the same as for a separate serviceInstalled according to Part D of Article 230, service entrance conductors; e.g.: 230.82(4), 230.2(A)(1), 230.72(B),Be capable of carrying the locked-rotor current (LRC) of the Fire Pump and all connected all equipment loads695.3(A)(1) & 695.6(D)

On-site Power Production FacilityThis is not a ordinary standby generator, but rather A facility that produces its own power on a Continuous basisSimilar to separate service requirementsLocated and protected to to minimize the risk of damage by fire


Multiple Power Sources - When NeededThe Term Reliable Is a Decision for The Authority Having Jurisdiction.Reliable Is Defined as Capable of Being Relied On; Dependable, or Trustworthy.All Sources Must Be Approved by The Authority Having Jurisdiction.695.3(B)

Multiple Power Sources - NFPA 20

Governed by NFPA-20 Section: 6-2.3 Other Sources

Excerpted into NEC Article:695.3. Power Sources(s) for Electric Motor-Driven Fire Pumps

Multiple Power Sources -- Other Electric Power Sources Where a Reliable Power Source is NOT available, redundant (Multiple) supplies are to be provided as follows:Another Service or Private Power StationOn-site standby GeneratorCombination of Feeders from Two Separate Utility SourcesCombination of One or More Feeders and an Onsite GeneratorDiesel Engine driven Fire PumpSteam Turbine driven Fire Pump

Examples of Multiple Power Sources 1) Dual Utility Service 2) Utility Service plus On-Site Gen-Set 3) Combination of Feeders from separate Services ** 4) Combination of Feeder and On-site standby generator **

** Only allowed on multi-building, campus style complexes.

Examples of Multiple Power Sources NFPA-20 Section 9.2, Power Sources(1) Combination of Services and/or On-site Power Facilities.Fire Pump ControllerService #1Service #2 MFire PumpMotor

Examples of Multiple Power Sources NFPA-20 Section 9.2, Power Sources(2) Combination of Service or OPF and On-site standby generator.MServiceOn-site standby GeneratorG Fire Pump Controller

Examples of Multiple Power Sources NFPA-20 Section 9.2, Power Sources(3) Combination of Feeders from separate Services.

Only allowed on multi-building, campus style complexes.Service #2Service #1High Voltage SubstationFeedersFire Pump Controller M

Examples of Multiple Power Sources NFPA-20 Section 9.2, Power Sources(4) Combination of Feeder and On-site standby generator.

Only allowed on multi-building, campus style complexes.On-site Standby GeneratorService FeedersFire Pump ControllerMHigh Voltage SubstationG

Examples of Multiple Power Sources NFPA-20 9.2, Power Sources (Tap Ahead . . .) The fire pump power supply shall not be disconnected when plant power is disconnected.The exception permits this only for multi-building, campus-style complexes that automatically ensure alternate power is still available.ServiceFeedersFire Pump ControllerM Plant Power Disconnect

Multiple Power Sources -On-site GeneratorGenerators to be of sufficient capacity to allow normal starting and running of the motor(s) driving the fire pump(s) while supplying all other simultaneously operated load(s). Where protective devices are installed, they must allow instantaneous pickup of full pump room load. E.g. Across-the-Line Starting of all pumps.Transfer of power to take place in the pump room Meet Both Voltage Drop Requirements (15% & 5%)

Multiple Power Sources -- On-site GeneratorGenerator to meet requirements for Level 1, Type 10, Class X system as defined by NFPA 110, Standard for Emergency and Standby Power SystemsLevel 1 - Critical to life safety. Type 10 - Power available within 10 secondsClass X - Sufficient fuel to run for a period of X hoursSufficient fuel supply so generator can operate for eight hours at 100% capacity of the pump and other demands (Class 8).

Multiple Power Sources -- Transfer of Power

Transfer Must Occur within the Pump Room

Arrangement I -- Combination Controller & Transfer Switch per NFPA-20 Section -or-Arrangement II -- Separate Field Wired Controller & Transfer Switch per NFPA-20 Section

Arrangement I Controller - Xfer. Switch CombinationA Combination Fire Pump Controller and Power Transfer Switch unit must . . .Be Listed as a coordinated designed and factory assembled and wired complete unitNeed have only Normal Side Breaker unless the Emergency Source is a Utility (need to specify Emergency Side Breaker when needed). Will already meet all requirements of NFPA-20, Section 10.8

Arrangement II Transfer Switch Ahead of ControllerA transfer switch ahead of a fire pump must . . .Be a Listed Fire Pump Power Transfer


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