A M E R I C A NN A T I O N A L S T A N D A R D NECA 406-2003 Standard for Installing Residential Generator Sets ® Published by National Electrical Contractors Association NECA 406-2003 Standard for Installing Residential Generator Sets An American National Standard ® Published by National Electrical Contractors Association <This page intentionally left blank> Table of Contents Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .v 1. 1.1 1.2 1.3 1.4 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 Equipment Included . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 Equipment Excluded . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 Related Items . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 Regulatory and Other Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 2. 2.1 2.2 2.3 Planning the Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 Whole House Design (One Panelboard) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 Essential Loads Design (Two Panelboards) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 Generator Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 3. 3.1 3.2 3.3 3.4 3.5 Selecting Other System Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Generator Output Conductors (Feeder) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 Transfer Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 Generator Disconnect Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 Utility Disconnect Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 Essential Loads Panelboard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 4. 4.1 4.2 4.3 4.4 4.5 4.6 Installing the Generator Set and Associated Components . . . . . . . . . . . . . . . . . . . . . . . . . 12 Generator Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Load Transfer Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Generator Disconnect Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Utility Disconnect Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 Essential Loads Panelboard—Location and Electrical Subfeed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 5. 5.1 5.2 5.3 Electrical Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 One Panelboard (Whole House Design) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 Two Panelboards (Essential Loads Design) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Control Circuitry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 6. 6.1 6.2 6.3 Final Installation Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 Generator Set Fuel Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Generator Set Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 Generator Set Coolant and Lubricant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 7. 7.1 7.2 7.3 Energizing and Testing the Generator Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 Pre-Energizing Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Starting Engine for the First Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Engine Governor Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 iii ■ NECA 406 Standard for Installing Residential Generator Sets 7.4 7.5 Voltage Regulator Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Performance Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 8. 8.1 8.2 Final Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 Site Clean-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 Punchlist and Acceptance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Annex A: Reference Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 ■ iv (This foreword is not a part of the standard) Foreword National Electrical Installation Standards ® are intended to improve communication among specifiers, purchasers, and suppliers of electrical construction services. They define a minimum baseline of quality and workmanship for installing electrical products and systems. NEIS® are intended to be referenced in contract documents for electrical construction projects. The following language is recommended: Generator sets for on-site power generation at one-family dwellings shall be installed in accordance with NECA 406-2003, Standard for Installing Residential Generator Sets (ANSI). Use of NEIS is voluntary, and the National Electrical Contractors Association assumes no obligation or liability to users of this publication. Existence of a standard shall not preclude any member or nonmember of NECA from specifying or using alternate construction methods permitted by applicable regulations. This publication is intended to comply with the edition of the National Electrical Code (NEC) in effect at the time of publication. Because they are quality standards, NEIS may in some instances go beyond the minimum requirements of the NEC. It is the responsibility of users of this publication to comply with state and local electrical codes when installing electrical products and systems. Suggestions for revisions and improvements to this standard are welcome. They should be addressed to: NECA Standards & Safety 3 Bethesda Metro Center, Suite 1100 Bethesda, MD 20814 (301) 215-4521 Telephone (301) 215-4500 Fax
[email protected] www.neca-neis.org To purchase National Electrical Installation Standards, contact the NECA Order Desk at (301) 215-4504 tel, (301) 215-4500 fax, or
[email protected]. NEIS can also be purchased in .pdf download format from www.neca-neis.org/catalog. Copyright © 2004, National Electrical Contractors Association. All rights reserved. Unauthorized reproduction prohibited. National Electrical Installation Standards, NEIS, and the NEIS logo are registered trademarks of the National Electrical Contractors Association. National Electrical Code and NEC are trademarks of the National Fire Protection Association,Quincy, Massachusetts. Cover image courtesy of Kohler Company, Kohler, WI. v ■ <This page intentionally left blank> 1. Scope 1.1 Equipment Included This standard describes installation procedures for the following: a) Generator sets permanently installed at one-family dwellings to provide backup power. These are usually rated 120/240 volts, single-phase, three-wire. However, some large homes have three-phase electrical systems and use backup generators rated 120/208 volts, three-phase, four-wire. b) Generator sets fueled by gasoline, natural gas, or liquified petroleum (LP) gas. 1.2 Equipment Excluded This standard does not cover installation procedures for the following: a) Generator sets supplying other types of buildings or facilities, including two- family and multifamily dwellings. These applications are covered by NECA/EGSA 404-2000, Recommended Practice for Installing Generator Sets (ANSI). b) Generators sets that use diesel fuel. These are also covered by NECA/EGSA 404. c) Marine or vehicle-mounted generators. d) Portable generators. 1.3 Related Items b) It also describes some electrical power distribution system design considerations related to the use of generator sets to supply loads in one-family dwellings. 1.4 Regulatory and Other Requirements a) All information in this publication is intended to conform to the National Electrical Code (ANSI/NFPA 70). Installers must always comply with the NEC, applicable state and local codes, manufacturers’ instructions, and project specifications when installing generator sets. b) Only qualified persons familiar with the installation, construction, and operation of generator sets should perform the work described in this publication. c) Residential areas often have strict sound level requirements at the property line. Installers should check local codes for the maximum sound level permitted. Meeting the required sound level may require the residential generator to have an optional sound-suppressing enclosure and residential muffler. d) General requirements for installing electrical products and systems are described in NECA 1-2000, Standard Practices for Good Workmanship in Electrical Contracting (ANSI). Other National Electrical Installation Standards provide additional guidance for installing particular types of electrical products and systems. A complete list of NEIS is provided in Annex A. a) This standard covers installation of related items such as transfer switch panels, disconnect switches, control panels, and fuel supply systems. 1 ■ 2. Planning the Installation Design of residential electrical distribution systems is outside the scope of this document. However, the design will determine how a backup generator is interconnected with the system to supply loads in a onefamily dwelling during a utility power outage. There are two basic design approaches. These affect the sizing of the generator, and the selection and ratings of other system components. Planning considerations are described in the following sections of this publication: 2.1 Whole House Design (One Panelboard) 2.2 Essential Loads Design (Two Panelboards) 2.3 Generator Sizing 2.1 Whole House Design (One Panelboard) a) The generator supplies the house service panelboard through a transfer panel (see Figure 1). The generator then supplies all house loads during a utili- Figure 1 ■ 2 ty power outage. b) This design approach requires a generator with a higher kVA output power rating to supply total house loads. It also requires use of larger generator output conductors, transfer panel, and generator disconnect switch. 2.2 Essential Loads Design (Two Panelboards) a) Circuits are classified as essential and non-essential, and grouped into two separate panelboards. The generator then supplies only the essential panelboard through a transfer panel (see Figure 2). b) The non-essential circuits fed from the main service panelboard are not energized during a utility power outage. Planning the Installation c) This design approach allows a generator with a lower kVA output power rating to supply only a subset of house loads. It also allows use of smaller generator output conductors, transfer panel, and generator disconnect switch. d) Essential Loads. Circuits to be considered “essential”and supplied from the essential loads panel should be determined in conjunction with the homeowner or builder whenever possible. The following are often considered “essential”loads. See 3.1.2(b). a) Refrigerator and freezer. b) Sump pump and/or well pump. c) Furnace blower. 2.3 Generator Selection 2.3.1 Generator Voltage Rating a) Supply voltage. Most single-family homes have 120/240V-1Ø-3W electrical distribution systems. Some larger homes have 120/208V-3Ø-4W electrical distribution systems. Select the proper generator voltage output for the home to be supplied. b) Dual windings. Some residential generator sets are supplied with two separate windings that each supply 120 volts. Connecting the two windings in series results in 240-volt output. Follow manufacturer’s instructions to configure dual-winding generators for either 120- or 240-volt output power. d) Air conditioning (in hot climates). 2.3.2 Generator Sizing e) Security system. The generator must be capable of supplying the maximum connected load, along with the required starting current of the largest motor. Follow these four steps to determine generator size, and see 2.3.3, Generator Sizing Example. f) Selected lighting outlets, such as outdoor security lights. g) Selected convenience receptacles, such as those supplying computers in a home office. Step 1. Determine the minimum generator size using the loads to be supplied. Add up the wattage of the various loads to be Figure 2 3 ■ NECA 406 Standard for Installing Residential Generator Sets served, using the nameplate information for all appliances. When appliance nameplate information is not available, use the values in Table 2.1, Typical Appliance Power Requirements. Include all luminaires (lighting fixtures) and lamps supplied from the generator to determine the light- Table 2.1 ing load. Include the starting wattage required by the largest motor. Step 2. Determine the minimum current rating of the generator based on the minimum power output rating determined in Step 1. Typical Appliance Power Requirements Load Running Watts Starting Watts Lights 15 - 150 0 Security System Refrigerator 250 900 Freezer Microwave Furnace Blower, 1/8 HP Furnace Blower, 1/6 HP Running Watts Starting Watts Washing Machine 1200 2300 0 2300 Fan, Attic Fan, Bathroom 350 100 400 900 1450 300 2300 0 500 Fan, Ceiling Fan, Fireplace Fan, Kitchen Exhaust 300 300 300 200 200 200 500 900 Garage Door Opener, 1/4 HP 550 1100 Furnace Blower, 1/4 HP 600 1100 Garage Door Opener, 1/3 HP 800 1700 Furnace Blower, 1/3 HP Furnace Blower, 1/2 HP Pump, 1/3 HP 800 1400 1000 2300 1000 800 2350 1400 Garage Door Opener, 1/2 HP Electric Blanket De-humidifier, Portable 400 650 0 800 Pump, 1/2 HP 1050 2150 Vacuum Cleaner 800 - 1100 0 Pump, 3/4 HP 1400 2200 Coffee Maker 1750 0 Pump, 1 HP 2000 3000 Toaster 1050 - 1650 0 Electric Range 6”Element Electric Range 8” Element 1500 0 Iron 1200 0 2100 0 Water Heater 4500 0 Oven Air Conditioner (Window Unit) 6000 1000 0 2800 Hair Dryer Television 300 - 1200 100 - 500 0 0 Dishwasher (Air Dry) Dishwasher (Heat Dry) Clothes Dryer, Gas Clothes Dryer, Electric 700 1450 1400 1400 Radio Computer 50-200 600 0 0 800 5750 1800 1800 Fax Machine Copy Machine 220 1500 0 0 ■ 4 Load Planning the Installation Step 3. Distribute and balance the loads on a panel schedule to calculate the current imbalance between phase conductors, using: Table 2.2 Load Distribution and Balance Schedule (120/240-volt, single-phase, three-wire generators) Table 2.3 Load Distribution and Balance Schedule (120/208-volt, three-phase, four-wire generators) Closely balance the loads between generator phase conductors. Highly unbalanced loads can result in overloaded phase conductors even when the total load is well below the generator power output rating. Overloaded conductors can result in circuit breaker and fuse operation, and generator shutdown. Where closely balanced loads are not possible, size the generator to supply the largest required phase current of the connected load. See Section 5.6 of NECA 407-2002, Recommended Practice for Installing and Maintaining Panelboards (ANSI) for detailed guidance in balancing loads. Step 4. Select a generator manufacturer’s standard product that has power and ampere ratings greater than the maximum connected load and the maximum unbalanced load current. 2.3.3 Generator Sizing Example Step 2. Determine the minimum load current rating using standard formulas: For a 120-volt generator, the minimum current rating is: 8800W = 73.33A 120V For a 120/240-volt, single-phase, three-wire generator, the minimum current rating is: 8800W = 36.67A 240V For a 120/208V-3Ø-4W generator, the minimum current rating (assuming 80 percent power factor) is: 8800W ( 3)(208V)(0.80PF) = 30.533A Step 3. Balance the loads: The following panelboard schedule is used as an example for a 120/240V-1Ø-3W generator. It is based on Table 2.2: (continued on page 8) Step 1. Determine the minimum generator size using the connected loads: Lighting (4 x 60 watts, 6 x 75 watts, and 1 x 135 watts) Freezer (use typical load from Table 2.1) Refrigerator (nameplate information) Sump Pump, 1/2 HP Furnace Blower, 1/4 HP Microwave (nameplate information) Attic Fan Ceiling Fans (3 x 300 watts) + 825 Watts 900 Watts 675 Watts 1050 Watts 600 Watts 1200 Watts 350 Watts 900 Watts Sub-Total, Connected Load: 6500 Watts Add Starting Wattage for Largest Motor (Sump Pump, 1/2 HP) Total - Minimum Generator Output Rating: + 2300 Watts 8800 Watts 5 ■ NECA 406 Table 2.2 Standard for Installing Residential Generator Sets Load Distribution and Balance Schedule (120/240-volt, single-phase, three-wire generators) Circuit Number Load Load Current (Amps) Watts Watts A Load Circuit Number B 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Totals: ■ 6 Planning the Installation Table 2.3 Load Distribution and Balance Schedule (120/208-volt, three-phase, four-wire generators) Phase A Circuit Number Load A W Phase B A W Phase C A W Circuit Number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Totals: 7 ■ NECA 406 Standard for Installing Residential Generator Sets Table 2.3.3 Panelboard Schedule Circuit Number Load Load Current (Amps) Watts Watts A 1 3 5 7 Totals: Microwave 1200 10.00 900 7.5 Sump Pump Lighting 825 6.88 350 2.92 Refrigerator 3275 27.30 The load currents for this example are well balanced between Phases A and B with magnitudes of 27.30 and 26.88 amperes, respectively. The calculated nameplate current for the 8800-watt generator is 36.67 amperes, which exceeds the maximum current unbalance calculated from the panelboard schedule, and appears adequate for the loads. NOTE: When distributing loads on a panel schedule, verify the operating voltages of the various loads, keep- ■ 8 Circuit Number Load B 2 Freezer 8.75 1050 7.50 900 4 Ceiling Fan 6 Attic Fan 5.63 675 5.00 600 26.88 3225 8 Furnace Blower ing in mind that some motors may be wired for 240volt operation, and that electric ovens and ranges may be wired for 120/240-volt operation. Step 4. Select the generator: Select the generator manufacturer’s standard product that is rated 8800 watts or greater, 36.67 amperes or greater, and 120/240V-1Ø-3W. 3. Selecting Other System Components Residential backup power systems have the following primary components. Selection procedures are described in the following sections of this publication: 3.1 Generator Output Conductors (Feeder) 3.2 Transfer Panel 3.3 Generator Disconnect Switch 3.4 Utility Disconnect Switch 3.5 Essential Loads Panelboard 3.1 Generator Output Conductors (Feeder) a) No main circuit breaker (MCB). If no generator disconnect is required and the manufacturer includes a means of generator overload protection, connect feeder conductors to the generator output terminals. The ampacity of the field-installed conductors from the generator output terminals to the first overcur- rent device must be at least equal to 115 percent of the rated full-load current. See Figure 3(a). b) Remote MCB. Some generator sets come with factory-supplied leads for connection to a separatelymounted remote main circuit breaker. When these leads have type CCXL insulation rated 125C, they may be a smaller AWG size than would be required for field installation. See Figure 3(b). c) Generator-mounted MCB. If the generator set comes supplied with a factory- installed MCB mounted on the assembly, the ampacity of the fieldinstalled conductors connected to the load terminals of the circuit breaker must be equal to or greater than the circuit breaker rating. See Figure 3(c). 3.2 Transfer Panel a) In some cases, a load transfer panel is furnished with the generator set. Figure 3 9 ■ NECA 406 Standard for Installing Residential Generator Sets b) When a transfer panel is not furnished by the generator manufacturer, the installer must provide a switch of the type (manual or automatic), load rating, and enclosure rating (NEMA/UL 1 or 3R) specified in the generator instructions. 3.2.1 c) Select the transfer switch based on the load to be switched and the configuration of the electrical distribution system. See 3.2.1 and 3.2.2. 3.2.2 Essential loads design (two panelboards) Whole house design (one panelboard) Figure 4 illustrates a generator set supplying a 200ampere service panel through a 200-ampere transfer panel. Figure 5 illustrates a generator set supplying a 60ampere essential loads panel through a 60ampere transfer panel. 3.2.3 Adapting three-phase transfer panel for single-phase applications The generator set selected may include a pre-packaged transfer panel configured for three-phase loads. To adapt this kind of panel for single-phase loads, follow these steps: a) Remove the three-phase Figure 4 Figure 5 ■ 10 Selecting Other System Components power monitor inside the enclosure. This is not used in a single-phase application. b) Locate the eight-pin octal relay socket in the transfer panel enclosure. Remove the wire N1A from its terminal and place it onto terminal 1. This removes the three-phase monitor from the sensing circuit. c) Connect the control wires as follows: 1. Connect the utility supply conductors to lugs N1 and N2. 2. Connect the load conductors to T1 and T2. 3. Connect the generator output conductors to lugs E1 and E2. 3.3 Generator Disconnect Switch a) The generator disconnect switch is installed between the generator set and the transfer switch, and used to disconnect the generator set for servicing (see Figures 1 and 2). In some cases it is furnished by the generator manufacturer. b) When this disconnect switch is not furnished by the generator manufacturer, the installer must supply a switch of the rating specified in the generator instructions. The generator disconnect switch is sized to handle the output power rating of the generator. c) The generator disconnect switch normally has a NEMA/UL 3R enclosure rating for installation outdoors near the generator set. 3.4 Utility Disconnect Switch a) The utility disconnect switch is installed between the utility watthour meter and the transfer switch, and used to disconnect the electrical power distribution system from the meter so that components can be serviced (see Figures 1 and 2). In some cases it is furnished by the generator manufacturer. c) The utility disconnect switch must have a NEMA/UL 1 enclosure rating for indoor installation, or a NEMA/UL 3R enclosure rating for outdoor installation. 3.5 Essential Loads Panelboard a) In this approach, the architect-electrical contractor-owner determine which loads will be considered essential. The NEC and other regulatory codes do not classify circuits of one-family dwellings in this way. See 2.2 d) for a list of typical essential loads. b) Under normal conditions of utility power supply, the essential panelboard is subfed from the service panelboard, through the transfer switch. Design and configuration of panelboards is outside the scope of this publication. See NECA 407-2002, Recommended Practice for Installing Panelboards (ANSI). 3.5.1 Installations at existing dwellings In some cases, new dwellings may be designed with two separate panelboards, one of which is intended to be supplied with backup power using a generator and transfer panel. For generator installations at existing dwellings, it will normally be the generator installer’s responsibility to furnish and install: a) Essential loads panelboard. b) Two- or three-pole circuit breaker in the existing service panelboard to subfeed the essential loads panelboard. c) Disconnect essential branch circuits from the existing service panelboard and connect them to the new essential loads panelboard. b) Disconnect switches with NEMA/UL 1 enclosures are listed for indoor installation. Disconnect switches with NEMA/UL 3R enclosures can be installed either outdoors or indoors. 11 ■ 4. Installing the Generator Set and Associated Components a) Thoroughly study the manufacturer’s instruction manuals, drawings, and other literature before attempting to install the generator set. In most cases, this information will already have been requested prior to the shipment of the generator set, to enable advanced planning. b) Residential generator systems have the following primary components. Installation procedures are described in the following sections of this publication: 4.1 Generator Set 4.2 Load Transfer Panel 4.3 Generator Disconnect Switch 4.4 Utility Disconnect Switch 4.5 Control Panel 4.6 Essential Loads Panelboard c) Electrical connections between the generator set, associated components, and the dwelling’s electrical distribution system are described in Section 5. 4.1 Generator Set Generator sets intended for residential use are normally self-contained units intended for outdoor installation. Location of the unit should comply with all applicable building codes and, at a minimum, the working space requirements of NEC 110.26. Also consider these factors when locating the generator set: a) Locate the unit as close as possible to the electrical service. b) Locate the unit as close as possible to its fuel supply. NOTE: Building codes or fire regulations in some jurisdictions may specify minimum allowable distances. ■ 12 c) Locate the unit where air inlet and exhaust openings will not be obstructed by leaves, grass, snow, etc. If prevailing winds may cause blowing or drifting, consider using a windbreak to protect the unit. d) Locate the unit on high ground where it will not be damaged by standing water. e) Allow sufficient room on all sides of the unit for maintenance and servicing. A good rule of thumb is to allow three feet of space on all sides. f) Locate the unit at least five feet from all building openings (doors, windows, vents) and insure that exhaust cannot accumulate inside the house. g) Install a foundation or mounting pad, as follows: • Some residential generators come supplied with prefabricated foundations, or shipping skids, that can be used as mounting pads. Install these in accordance with the manufacturer’s instructions. • If a mounting pad is not provided by the generator manufacturer, the installer must provide a concrete slab at least 3 inches thick and extending at least 3 inches beyond the generator set enclosure on all sides. This pad should include Type J bolts (sometimes called Type L bolts) to anchor the unit. 4.1.1 Lifting generator set into place a) Residential generator sets may exceed 300 pounds in weight. Some manufacturers supply temporary lifting lugs that can be used to lift the generator (see Figure 6). Some generator sets are shipped with oil in the crankcase, so be careful not to tip the unit on its side. Installing the Generator Set and Associated Components b) Lifting procedures for larger, heavier generator sets are covered in NECA/EGSA 404-2000, Section 2. system using an appropriately-sized equipment grounding conductor. 4.1.2 Vibration isolators c) Flexible metallic tubing, flexible metal conduit, or liquidtight flexible metal conduit are often used to enclose power output conductors from the generator set to transfer switch, in order to provide vibration isolation. These flexible raceways should not be relied upon as a means for equipment grounding. Provide a separate equipment grounding conductor originating at the service panelboard for all residential generator set installations. Bolting a generator set directly to the foundation or mounting pad will result in excessive noise and vibration and possible damage. Install vibration isolators supplied by the generator set manufacturer at locations shown on the manufacturer’s instructions. 4.1.3 Seismic vibration isolation Carefully follow the plans and specifications when anchoring a generator set for seismic conditions. NOTE: Local building codes may have seismic requirements that affect generator set installation. Installers should consult these codes, or coordinate with the general contractor or authority having jurisdiction, prior to installing generator sets. 4.1.4 4.2 Load Transfer Panel Load transfer panel selection and ratings are covered in 3.2. Locate and install the transfer panel as described below: a) Locate the transfer panel as close as possible to the panelboard(s) that it supplies (see Figures 1 and 2). Grounding a) In most installations, a separate ground rod is not provided for the generator set. However, some local codes may require a separate generator ground rod. When a separate local ground rod is installed, it must be bonded to the grounding electrode system of the house as required by NEC 250.30(A)(1). b) A lug for a grounding electrode conductor is typically located on the frame of the generator set. Connect the generator set to the grounding electrode b) Transfer switches with NEMA/UL 1 enclosures are listed for indoor installation. Transfer switches with NEMA/UL 3R enclosures can be installed either outdoors or indoors. 4.3 Generator Disconnect Switch Generator disconnect switch selection and ratings are covered in 3.3. Locate and install the transfer switch as described below: a) Locate the disconnect switch as close as possible to the generator (see Figures 1 and 2). The National Electrical Code requires that the disconnect be within 50 feet of the generator and within sight of it. b) Normally the generator set disconnect switch will have a NEMA/UL 3R enclosure for outdoor installation. 4.4 Utility Disconnect Switch Utility disconnect switch selection and ratings are covered in 3.4. Locate and install the disconnect as described below: Figure 6 13 ■ NECA 406 4.4.1 Standard for Installing Residential Generator Sets Whole house design (one panelboard) a) Locate the utility disconnect switch between the utility watthour meter and service panelboard (see Figure 1). b) Disconnect switches with NEMA/UL 1 enclosures are listed for indoor installation. Disconnect switches with NEMA/UL 3R enclosures can be installed either outdoors or indoors. 4.4.2 Essential loads design (two panelboards) a) Locate the utility disconnect switch between the utility watthour meter and transfer switch (see Figure 2). b) Disconnect switches with NEMA/UL 1 enclosures are listed for indoor installation. Disconnect switches with NEMA/UL 3R enclosures can be installed either outdoors or indoors. 4.5 4.6 Essential Loads Panelboard - Location and Electrical Subfeed a) When a separate essential loads panelboard will be installed, locate it as close as possible to the transfer panel. b) Installing panelboards is outside the scope of this publication. See NECA 407- 2002, Recommended Practice for Installing and Maintaining Panelboards (ANSI). 4.6.1 Electrical subfeed a) Under normal conditions of utility power supply, the essential panelboard is subfed from the service panelboard, through the transfer panel. See 5.2.2 for wiring connections. Control Panel Some residential generators are supplied with a control panel separate from the generator set. Mount ■ 14 the control panel indoors, following manufacturers’ instructions. b) In most cases the feeder will be rated 120/240V1Ø-3W . In some cases the feeder may be rated 120/208V-3Ø-4W. 5. Electrical Connections Wiring connections are different for the whole house and essential loads power distribution system designs. They are described in the following sections of this publication: 5.1 Whole House Design (One Panelboard) 5.2 Essential Loads Design (Two Panelboards) 5.1 One Panelboard (Whole House Design) See Figure 4. 5.1.2 Generator set, transfer panel a) Size of the generator output conductors was determined during system planning (see 2.3). b)Install output conductors from the generator set to the standby supply terminals and neutral lug of the load transfer panel. 5.2 Two Panelboards (Essential Loads Design) See Figure 5. 5.1.1 Utility meter, utility disconnect, transfer panel, panelboard 5.2.1 a) Connect the incoming supply conductors from the utility meter to the line terminals and neutral lug of the utility disconnect switch. Normally this will be a 120/240V-1Ø-3W service. In some larger homes, the utility service may be 120/208V-3Ø-4W. Connect the incoming supply conductors from the utility meter to the main OCPD terminals and neutral bus of the service panelboard. Normally this will be a 120/240V-1Ø-3W. In some larger homes, the utility service may be 120/208V-3Ø-4W. NOTE: In existing dwellings, this connection will already exist. b) In existing dwellings, this will require disconnecting the utility supply conductors from the existing service panelboard. It may be necessary to install a pullbox, wiring trough, etc., to accomplish this. 5.2.2 Service panelboard, transfer panel, and essential loads panelboard c) Conductors from the utility disconnect to transfer panel are same size as the incoming utility conductors. Install these conductors from the load terminals and neutral lug of the utility disconnect to the normal supply terminals and neutral lug of the load transfer panel. d) Conductors from the transfer switch to service panelboard are the same size as the incoming utility conductors. Install these conductors from the output terminals and neutral lug of the load transfer panel to the main overcurrent protective device (OCPD) terminals and neutral bus of the panelboard. Utility meter, service panelboard a) Rating of essential loads panelboard and size of the supply conductors (either 120/240V-1Ø-3W or 120/208V-3Ø-4W) was determined during system planning (see 2.3). b) Install a two- or three-pole circuit breaker in the service panel to subfeed the essential loads panelboard. c) Install conductors from the load terminals of this subfeed breaker and the neutral bus of the service panelboard to the normal supply terminals of the load transfer panel. d) Conductors from the load transfer panel to essential loads panelboard are same size as the subfeed 15 ■ NECA 406 Standard for Installing Residential Generator Sets conductors from the service panelboard. Install these conductors from the output terminals and neutral lug of the transfer panel to the main OCPD terminals and neutral bus of the essential loads panelboard. 5.3 Control Circuitry Some residential generator sets come supplied with a remote control panel, or engine start controls on the transfer panel. Install interconnecting control wiring to the generator set in accordance with the manufacturer’s instructions. ■ 16 6. Final Installation Procedures Follow these procedures to complete the installation of the generator set and standby power system. They are described in the following sections of this publication: d) Filter. A dry fuel filter should be installed in each line to protect sensitive pressure regulating components and orifices downstream from harmful foreign substances carried along in the gas stream (rust,scale, etc.). 6.1 Generator Set Fuel Supply 6.2 Generator Set Battery 6.1.3 Gaseous fuel load block adjustments 6.3 Generator Set Coolant and Lubricant Gas-fueled generators are typically designed to operate using either natural gas or LP gas. Field adjustments are needed during installation depending on the fuel selected. Adjust the generator’s gaseous fuel block for either natural gas or LP gas, following the manufacturer’s instructions. 6.1 Generator Set Fuel Supply Residential generators typically use one of three fuels: gasoline, natural gas, or liquified petroleum (LP) gas. This standard does not cover diesel-fueled generators. 6.2 6.1.1 Gasoline Fill the generator’s fuel tank with automotive gasoline of the grade recommended by the manufacturer. 6.1.2 Natural gas and LP gas Install the gaseous fuel supply system as follows. NOTE: Building codes or regulations in some jurisdictions may requires that natural gas supply hose or piping be installed by a licensed plumber. a) Regulator. Most installations include a service gas pressure regulator. Building codes require that gas pressure be vented to the outdoors. b) Vibration isolation. Use approved flexible fuel hose for connections at the engine to take up generator set movement and vibration. c) Shutoff valves. Most building codes require both manual and electric (battery- powered) shutoff valves between permanently-installed gas piping and flexible fuel hoses. The manual valve should be of the indicating type. Generator Set Battery a) Purchase a fully charged battery of the type specified in the manufacturer’s instructions. b) Make sure the generator’s Manual-Off-Auto switch is set to OFF. c) Disconnect the utility power supply by opening, locking, and tagging the generator disconnecting means or transfer switch. d) Install battery inside the generator set enclosure. Connect the red battery cable from the starter to the battery post identified as POS, positive, or (+). Connect the black cable from the frame/enclosure ground to the battery post identified as NEG, negative, or (-). 6.3 Generator Set Coolant and Lubricant a) Residential generators come in both air-cooled and water-cooled models. If this generator is equipped with a radiator, fill it with water (and in colder climates, antifreeze solution), following manufacturer’s recommendations. b) If necessary, add the grade of engine oil recommended by the manufacturer. 17 ■ 7. Energizing and Testing the Generator Set Hazards exist in energizing a generator set, and this should only be performed by qualified electrical personnel. If a short-circuit or ground-fault condition exists caused by damage or poor installation practices, and this is not detected and corrected during the checkout procedures, serious personal injury and/or damage to the generator set can result when the generator set is first energized. Generator set manufacturers’ instructions typically specify procedures to be followed when energizing a generator set for the first time. If such instructions are not available, follow these general guidelines. 7.1 Pre-Energizing Procedures 7.2 Starting Engine for the First Time 7.3 Engine Governor Adjustment 7.4 Voltage Regulator Adjustment 7.5 Performance Testing 7.1 Pre-Energizing Procedures a) Power connections. Check all field installed power connections for correct torque value. b) Grounding and bonding. Check the generator set equipment grounding conductor electrode connection, bonding connections, and system grounded conductor (neutral). c) Clearances. Check to insure that dents or other damage to the enclosure have not resulted in clearances that violate NEC requirements, or will interfere with moving parts. d) Packing materials. Remove foam blocks, packing material, and temporary cushioning from the genera■ 18 tor and associated components. e) Miscellaneous. Check all relays, meters and instrumentation device wiring and terminations. f) Engine check • Check radiator coolant and lubricating oil levels, and add additional fluids if needed. Inspect the radiator and coolant hoses for leaks; leaking or damaged hoses should be re-tightened or replaced as required. • Check drive belts to insure they are in good condition and properly tensioned; adjust or replace as necessary. • Check engine mounting bolts for tightness; retighten if necessary. 7.2 Starting Engine for the First T ime a) Insure that all pre-energizing procedures in 7.1 have been completed correctly. b) Press the starter switch. c) If engine fails to start within 30 seconds, release the starter switch and allow the starting motor to cool for two minutes before trying again. d) If engine fails to start after four attempts, conduct an inspection to determine the cause. 7.3 Engine Governor Adjustment If the generator AC output voltage or frequency are outside of manufacturer’s specifications, adjust the engine governor following manufacturer’s instructions. Energizing and Testing the Generator Set 7.4 Voltage Regulator Adjustment Some residential generators are equipped with voltage regulators in addition to engine governors. If the output AC power frequency is correct but the voltage is not within the specified tolerances, adjust the voltage regulator following manufacturer’s instructions. 7.5 Performance Testing a) For routine operational checks and load tests, run the engine at no load for about five minutes to warm up. b) Apply a load equal to or greater than 35 percent of the generator nameplate rating. c) Operate the unit until temperatures stabilize. 19 ■ 8. Final Procedures 8.1 Site Clean-Up a) Vacuum all scrap, wire, dust and other debris from the generator, transfer switch, panelboard(s), and associated equipment. Do not use compressed air to blow debris out of the generator, since is may cause debris to settle inside devices and impair their ability to function. d) Dispose of non-recyclable packing materials appropriately. 8.2 Punchlist and Acceptance a) Walk through project with owner/architect/general contractor. b) Touch-up and repair all minor defects. b) Replace all parts and covers. Check for any pinched wires and close all doors. Make sure the enclosure parts are properly aligned and fastened securely. c) When recycling options are available at the job site, separate used packing materials by type and recycle them. ■ 20 c) Turn over all manuals, spare parts, and a set of special tools (where required) for generator adjustments or tamper-proof hardware, to the owner/architect/general contractor owner. Obtain a delivery receipt. (This annex is not part of the standard) Annex A: Reference Standards This publication, when used in conjunction with the National Electrical Code and generator manufacturers’ literature, provides sufficient information to install and maintain generator sets. The following publications may also provide useful information: National Fire Protection Association 1 Batterymarch Park P.O. Box 9101 Quincy, Massachusetts 02269-9101 (617) 770-3000 tel (617) 770-3500 fax www.nfpa.org NFPA 37-2002, Standard for the Installation and Use of Stationary Combustion Engines and Gas Turbines NFPA 70-2002, National Electrical Code (ANSI) NFPA 110-1999, Emergency and Standby Power Systems (ANSI) National Electrical Manufacturers Association 1700 North Thirteenth Street, Suite 1847 Rosslyn, VA 22209 (703) 841-3200 tel (703) 841-3300 fax www.nema.org MG 2-1989 (R1994), Safety Standard for Construction and Guide for Selection, Installation, and Use of Electric Motors and Generators Current National Electrical Installation Standards® published by NECA: NECA 1-2000, Standard Practices for Good Workmanship in Electrical Contracting (ANSI) NECA 100-1999, Symbols for Electrical Construction Drawings (ANSI) NECA 101-2001, Standard for Installing Steel Conduits (Rigid, IMC, EMT) NECA/AA 104-2000, Recommended Practice for Installing Aluminum Building Wire and Cable (ANSI) NECA/NEMA 105-2002, Recommended Practice for Installing Metal Cable Tray Systems (ANSI) NECA 111-2003, Standard for Installing Nonmetallic Raceways (RNC, ENT, LFNC) (ANSI) NECA 200-2002, Recommended Practice for Installing and Maintaining Temporary Electrical Power at Construction Sites (ANSI) 21 ■ NECA 406 Standard for Installing Residential Generator Sets NECA 202-2001, Recommended Practice for Installing and Maintaining Industrial Heat Tracing Systems (ANSI) NECA 230-2003, Standard for Selecting, Installing and Maintaining Electric Motors and Motor Controllers (ANSI) NECA/FOA 301-1998, Standard for Installing and Testing Fiber Optic Cables NECA 305-2001, Standard for Fire Alarm System Job Practices (ANSI) NECA 400-1998, Recommended Practice for Installing and Maintaining Switchboards (ANSI) NECA 402-2001, Recommended Practice for Installing and Maintaining Motor Control Centers (ANSI) NECA/EGSA 404-2000, Recommended Practice for Installing Generator Sets (ANSI) NECA 405-2001, Recommended Practice for Installing and Commissioning Interconnected Generation Systems (ANSI) NECA 406-2003, Standard for Installing Residential Generator Sets (ANSI) NECA 407-2002, Recommended Practice for Installing and Maintaining Panelboards (ANSI) NECA 408-2002, Recommended Practice for Installing and Maintaining Busways (ANSI) NECA 409-2002, Recommended Practice for Installing and Maintaining Dry-Type Transformers (ANSI) NECA/IESNA 500-1998, Recommended Practice for Installing Indoor Commercial Lighting Systems (ANSI) NECA/IESNA 501-2000, Recommended Practice for Installing Exterior Lighting Systems (ANSI) NECA/IESNA 502-1999, Recommended Practice for Installing Industrial Lighting Systems (ANSI) NECA/BICSI 568-2001, Standard for Installing Commercial Building Telecommunications Cabling (ANSI) NECA/MACSCB 600-2003, Recommended Practice for Installing and Maintaining Medium-Voltage Cable (ANSI) ■ 22 N A T I O N A L E L E C T R I C A L I N S T A L L A T I O N ® National Electrical Contractors Association 3 Bethesda Metro Center Suite 1100 Bethesda, MD 20814 301-657-3110 fax: 301-215-4500 www.neca-neis.org Standards & Safety Index: NECA 406 7K/2-04 S T A N D A R D S ®