NEW SERVICE HANDBOOK

Transcription

1 NEW SERVICE HANDBOOK

2 LOCATING UNDERGROUND UTILITIES CHECK SHEET cut here Will you be working within ten feet of any overhead power lines? Yes No Type of work Work being done for County Nearest City Address or road where upon work will take place Nearest intersecting road Distance and direction from intersecting road Location of work (where digging will take place) Mark with white paint Comments Township Range Section Section Township Range Section Section Copy of ticket received from Utilities Underground Location Center (UULC)? YES NO To the best of your knowledge, is the information provided above correct? YES NO Signature of Approval Missoula Electric Cooperative, Inc. Owned By Those We Serve

3 TABLE OF CONTENTS Forward, Acknowledgements, Notice... 1 Introduction... 2 Temporary Service... 2 Residential Service... 3 Small Commercial Service... 3 Primary Voltage Service... 3 Large Commercial Service... 4 Industrial... 4 Overhead Services Secondary Overhead Line Clearances... 5 Checklist for Installing Overhead Services... 6 Underground Services Trenching Conduit Meter Installations General Requirements for Meter Sockets Current Transformer Metering Irrigation Services Glossary MISSOULA ELECTRIC COOPERATIVE, INC W. Broadway Missoula, MT Fax

4 FOREWORD Missoula Electric Cooperative s New Service Handbook aims to provide line workers, meter installers, customer service representatives, contractors and customers with a clear description of the respective responsibilities of Missoula Electric Cooperative and the customer in the new installation of new temporary, residential, irrigation or commercial electric services. ACKNOWLEDGEMENTS This handbook is largely based on the model handbook provided by Richard Alexander which in turn draws from materials in the National Electric Code by the National Fire Protection Association and the National Electrical Safety Code by the Institute of Electrical and Electronics Engineers. In addition, Richard Alexander s model was developed in consultation with regional and local references including standards written by the Electric Utility Service Equipment Requirements Committee (EUSERC), PacifiCorp, Puget Sound Energy, Florida Power Corporation, Pennsylvania Power and Light, and Tacoma Public Utilities. We gratefully acknowledge the contribution of each of these sources. NOTICE Missoula Electric Cooperative, Inc. does not assume any liability with respect to the use of any information in this publication. Page 4 New Service Handbook

5 INTRODUCTION Installing a new electric service is a joint project between the customer and Missoula Electric Cooperative (MEC). To insure a smooth installation of new service, it is necessary to recognize which tasks and equipment procurement are the responsibility of the customer and the ones that are the responsibility of MEC. This handbook describes in detail these two areas of responsibility as they apply to various types of electric service and installation configurations. With this information, the customer and electrical contractor, as well as MEC personnel will be better equipped to facilitate new service installations. MEC constructs, operates, maintains, and owns all power lines and equipment up to the point where the power the customer uses is metered. MEC also supplies the power and owns the meter. MEC owned or maintained equipment shall be outside and readily available to MEC employees without entering a structure. MEC normally applies for special permits needed from such agencies as state and county government, the U.S. Forest Service, and railroads. MEC will also provide assistance in obtaining private easements. TEMPORARY SERVICE After the required right-of-way has been secured, the consumer will need to cut and trim trees in order to allow MEC to complete the initial installation of new power lines. Overhead lines generally require a minimum of ten feet clearance around the wires. Underground lines require five feet clearance on either side of the wire path. Once the line has been installed, MEC reserves the right to maintain the right of way. This includes removing dead, weak, or leaning trees that may endanger the power lines or other MEC property. The customer is responsible for all wiring and needed electrical permits on the load side from metering. The customer is normally required to obtain whatever easements are needed to cross private ground and is responsible for the restoration of driveways and lawns that have been disturbed in conjunction with the installation of new electric service. For the safety of our crews and the public, attachments such as basketball hoops, clotheslines, customer lighting and similar items are not allowed on MEC-owned poles, transformers, or any other MEC-owned structure. Temporary service is defined as electric service provided to a site for less than one year. Typically, temporary service will be required during the construction phase of a project. When the project is complete, the temporary service is replaced by a permanent service. The total cost of installing and removing the temporary service must be paid in advance. (Fig. 1) Fig. 1 Temporary service fed from overhead Temporary service fed from underground Missoula Electric Cooperative Page 5

6 RESIDENTIAL SERVICE Residential service is defined as service to a single-family residence, recreational cabin, stock water pump, or to an individually metered multi-family residence such as an apartment or condominium. Each residential service must have an external disconnect. An easement shall be provided for placement of all MEC-owned facilities. Full use of the property by the owner is permitted so long as it does not conflict with the maintenance and operation of the power lines. For example, buildings and tall trees are not allowed in an overhead right-of-way; fences, gardens and roads are allowed. Please contact the MEC engineering department for details in any specific case. Voltage for residential service is 120/240 volts. The minimum residential service installed by MEC is 200 amps. SMALL COMMERCIAL SERVICE Small commercial service is defined as electric service to a commercial or business site. Typical examples of business sites are stores, offices, garages, taverns, hotels, motels or small industries who require installation of 50 KVA demand and/or have the following metering requirements: Single phase, 240 volt, 400 amps and less Single phase, 480 volt, 200 amps and less Multi phase, 208/240/480 volt, 100 amps or less NOTE: Each small commercial service is required to have an external main disconnect. MEC prohibits the reselling of power. It is prohibited to place a customer-owned meter or meters on the load side of any MEC-owned meter for the purpose of reselling power. PRIMARY VOLTAGE SERVICE MEC can provide primary voltage service (over 600 volts) to qualified customers directly at the high voltage or primary distribution system standard for the location at which service is requested. Primary service is available subject to the following conditions: In the opinion of MEC, the service will not adversely affect service to other customers or to MEC s distribution system. MEC power shall not be resold. Customers receiving service at primary voltage may own poles, conductors, cables, transformers, and protective devices, but all such equipment and materials are subject to approval by MEC. Customer-owned equipment shall be of the same type or specifications as equipment used by MEC. This will help to assure timely restoration of service in case of failure. The customer shall provide and maintain an agreement with a licensed electrical contractor who is qualified for operation and maintenance of the primary system. Primary voltage service is metered using current transformers, voltage transformers, and transformer-rated meters. Buried primary cables must have a minimum of 36 inches cover from the top of the conduit or conductor to the finished grade. Written approval from MEC has been obtained prior to construction. The location of the point of delivery, primary metering equipment, disconnect devices to separate MEC and customer distribution systems, safeguards against ferroresonance and harmonic levels, and system and grounding methods all have been approved by MEC. LARGE COMMERCIAL SERVICE Large commercial service is defined as electric service to a commercial or business site which requires installation of greater than 50 KVA demand and/or has the metering requirements shown in Table 2 below. Typical examples of business sites requiring large commercial service are stores, offices, garages, taverns, hotels, motels or small industries. Single phase, 240 volt, 400 amps or greater Single phase, 480 volt, 200 amps or greater Multi phase, 208/240/480 volt, greater than 100 amps NOTE: Every service is required to have an external main disconnect Page 6 New Service Handbook

7 INDUSTRIAL This classification includes all loads that require the installation of demand capacity of 1000 KVA or greater. OVERHEAD SERVICES The cost for overhead service depends on the length of the line extension. The least complicated and most cost-effective situation occurs when a transformer already exists on a pole near the property. MEC may install a meter loop at the pole. Alternatively, the customer may install the service entrance equipment on their property. The electrical inspector shall inspect service equipment, then call MEC to have the service connected. The customer is responsible for obtaining, installing, and maintaining all equipment on the load side of the point of delivery, except for the meter. MEC is responsible for providing and installing the meter, completing the connections between the meter and the service conductors, and making the final connections at the point of delivery. If current transformers and power transformers (CTs/PTs) are being used, MEC also provides the CTs/PTs and makes the connections to them and to the meter. MEC owned or maintained equipment shall be outside and readily available to MEC employees without entering a structure. Figure 2 shows a finished overhead service installation using a service mast. The customer provides everything shown here except the meter, the overhead service line, the power pole and the pole-mounted equipment. After the customer installs the required equipment, MEC strings the service line, connects the service line supporting wire (neutral) to the insulated clevis, and splices the conductors together. MEC then installs the meter in the meter socket. Fig. 2 TRANSFORMER WEATHERHEAD SERVICE LINE POWER POLE SERVICE ENTRANCE CONDUCTOR SPLICE (POINT OF DELIVERY) SERVICE MAST SERVICE MAST GUY POINT OF ATTACHMENT METER METER SOCKET Missoula Electric Cooperative Page 7

8 SECONDARY OVERHEAD LINE CLEARANCES Figures 3 and 4 show clearances under overhead lines for most commonly encountered conditions. For other situations and for details, see the National Electric Code and the National Electric Safety Code, which will differ slightly from each other, and contact the electrical inspector for your area. These are minimum clearances, MEC requirements exceed these codes in many specifics. The customer does not string the service conductor, but is required to provide a point of attachment high enough and strong enough to allow MEC to install the service line and maintain the required clearances. If the span of the service line exceeds 125 feet, an intermediate support pole may be required to relieve the tension on the service mast. CLEARANCES FROM GROUND Fig. 3 STATE HIGHWAY STREET, ALLEY, COUNTY ROADS, AND DRIVEWAYS LOWEST POINT OF SERVICE CONDUCTOR DRIP LOOP 24 1/2 16 (NESC) (NEC) 12 RESIDENTIAL PROPERTY 10 CLEARANCES OVER OTHER STRUCTURES Fig. 4 ROOF WITH PERMANENT ACCESS ROOF WITHOUT PERMANENT ACCESS /2 ELECTRIC METER 3 PREFERRED DECK GAS METER Avoid a route for the service line that passes over a driveway. Lines which cross driveways can be struck by tall trucks and other vehicles endangering the vehicles and causing damage to the service equipment and to the building. If the service line will pass through trees, the customer must prune the trees to provide a clear path for the line. If the service line will pass over brush, the customer must clear a path for access by MEC s installation service personnel. Page 8 New Service Handbook

9 CHECKLIST FOR INSTALLING OVERHEAD SERVICE The customer is responsible for obtaining, installing, and maintaining all equipment to the load side of the point of delivery, except for equipment related to the meter. MEC is responsible for providing and installing the meter, completing the connections between the meter and the service conductors, and making the final connections at the point of delivery. If CTs/PTs are being used, MEC also provides the CTs/PTs and makes the connections between them and the meter. MEC-owned or maintained equipment shall be outside and readily available to MEC employees without entering a structure. To obtain new overhead service, the customer: Checks if local regulations permit the installation of overhead service. Note: The service line strung from the power pole to the meter location must not cross property belonging to others. Refer to Figures 3 & 4 for details on overhead line clearances. Contacts MEC to request membership and a new service. MEC will then select a location for the meter. Obtains an electrical work permit from the state, city or county. Installs the service equipment at the building, or MEC provides a meter base near the transformer. Obtains an electrical inspection after all work is complete, and has the approval sent to MEC. MEC then: Strings the wires from the pole-mounted transformer to the mast. Connects the neutral supporting line to the insulated clevis on the mast. Splices the service line conductors. Installs the meter in the meter socket. Figure 5 shows details of a service mast, with the meter mounted on the surface of the building. The service shall be wired to an exterior meter as shown in Figure 5. The customer installs everything in Figure 5, except the meter. After the customer installs the service equipment, MEC strings the service line, connects the service line supporting wire (neutral) to the insulated clevis, splices the conductors together, and installs the meter in the meter socket. Fig. 5 SERVICE ENTRANCE CONDUCTORS 18 OUT OF WEATHERHEAD TOP OF SERVICE MAST AT LEAST 13 ABOVE FINAL GRADE NO JOINT ALLOWED IN SERVICE MAST ABOVE ROOF LINE IF OVER 26, A GUY IS REQUIRED WEATHERHEAD INSULATED CLEVIS MAX. GUY ATTACHMENT OVERHANG NEEDED TO PROTECT METER FROM SNOW AND ICE 2 X6 INSTALLED SOLIDLY BETWEEN RAFTERS AND AGAINST ROUGH SHEATHING 5/16 U-BOLTS 2 RIGID CONDUIT METER SOCKET EXTERNAL DISCONNECT 2 X6 INSTALLED SOLIDLY BETWEEN STUDS AND AGAINST ROUGH SIDING WITH U-BOLTS 2 APART SHIM METER SOCKET AND FASTEN WITH SCREWS STUD Missoula Electric Cooperative Page 9

10 SERVICE MAST FOR FLUSH-MOUNT METER Figure 6 shows the details of a service mast, with the meter mounted flush with the surface of the building. Flush-mount meters are sometimes installed for aesthetic reasons. The service shall be wired to an exterior meter as shown in Figure 6 The customer is responsible for everything in Figure 6, except the meter. After the customer installs the service equipment, MEC strings the service line, connects the service line supporting wire (neutral) to the insulated clevis, splices the conductors together, and installs the meter in the meter socket. Fig. 6 TOP OF SERVICE MAST AT LEAST 13 ABOVE FINAL GRADE SERVICE ENTRANCE CONDUCTORS 18 OUT OF WEATHERHEAD IF OVER 26, A GUY IS REQUIRED 18 WEATHERHEAD INSULATED CLEVIS NO JOINT ALLOWED IN SERVICE MAST ABOVE ROOF LINE OVERHANG NEEDED TO PROTECT METER FROM SNOW AND ICE EXTERIOR SIDING 10 FROM CENTER OF METER U-BOLT NEAR TOP PLATES 2 RIGID CONDUIT U-BOLT MAY BE BOLTED TO STUD ON SIDE GUY ATTACHMENT Fig. 7 METER SOCKET EXTERNAL DISCONNECT SERVICE LINE EXTENDS AT A 45 ANGLE FROM WITHIN BRACES 2 X4 BRACE 2 REQUIRED OR MORE CLEARANCE FOR DRIP LOOP 4 X4 POST METER SOCKET WITH MAIN DISCONNECT OVERHEAD SERVICE, METER POST FOR TEMPORARY SERVICE Figure 7 shows a finished installation for temporary service, using a meter post. The service is overhead from MEC to the post. From the post, the service to the building could be overhead or underground. The customer provides everything shown in Figure 7, except the meter and the overhead service line. After the customer installs the service equipment, MEC strings the service line, connects the service line supporting wire (neutral) to the insulated clevis, splices the conductors together, and installs the meter in the meter socket. 2 X4 STAKE 2 REQUIRED SET IN GROUND 2 BELOW GRADE 8 2 GROUND RODS 6 APART APPROX. 5 1/2 GROUND WIRE Page 10 New Service Handbook

11 UNDERGROUND SERVICE The cost for underground service depends on several factors including labor, materials and engineering required. The least complicated and most cost effective situation is when a pad-mount transformer or junction box is already on the property. In this case MEC simply installs the meter pedestal equipment, and requires the customer to have an electrical permit. A customer-owned meter base may be installed on the customer s structure. MEC is responsible for: Providing, installing, and maintaining all equipment to the metering point. Providing and installing the meter, completing the connections between the meter and the service conductors, and making the final connections at the metering point. If CTs/PTs are being used, MEC also provides the CTs/PTs and makes the connections to them and to the meter. CHECKLIST FOR INSTALLING UNDERGROUND SERVICE To obtain new underground service, the customer: Contacts MEC to request membership and a new service. Shall provide MEC with: 1. Site drawings. 2. Load information. 3. A minimum of a ten foot wide utility easement for equipment owned by MEC and installed on the customer s property and/or all properties concerned. 4. Payment for construction costs. (Cost analysis is valid for 90 days.) Obtains an electrical work permit from the state, city or county. Selects the type of meter installation that fits the situation from the following options: 1. Surface-mount meters - see Figure 5 (page 6). 2. Flush-mount meter - see Figure 6 (page 7). 3. Pedestal-mount meters - see Figure 13 (page 13). Installs the service entrance equipment as required and obtains an inspection from the proper authority. Calls the locating service (Call Before You Dig) to locate any existing underground wires, cables, or pipes. The telephone number is 811. Provides a trench from the connection point to the meter location. Refer to Figures 9 and 10 (pages 9 & 10). NOTE: MEC must inspect all trench applications to verify they meet MEC requirements. Trenches must be backfilled prior to requesting MEC energize any cable. Refer to Figures 9 and 10. Back-fills the wire/conduit in the trench per NEC requirements, and is responsible for compaction, and site restoration. LOCATING UNDERGROUND UTILITIES The underground utilities locating service must be contacted at least two full working days (48 hours) prior to the proposed excavation start date and no excavation may take place prior to the utilities being marked. The phone number for the locating service is 811 for projects located Montana and for projects located in Idaho. One call to the locating service notifies all utilities that locates are required. In some of MEC s service areas, not all utilities are members of the one-call system. To determine if the service is located in one of those areas, the customer must contact one of the telephone numbers above. Excavation must not begin until the locations of underground wires, cables, and pipes have been marked, or the utilities have informed the customer that they have no facilities in the area. There shall be no digging within 24 inches of power lines or equipment. The table to the right indicates the color code for marking underground utilities. Color Underground Service Missoula Electric Cooperative Page 11

12 TRENCHING The customer is responsible for all trenching, inspections, back-fills, and compacting of the trench per NEC and NESC requirements. Trenching rules and tips: Dig trenches in straight lines between takeoff points, to the greatest extent possible. Trench to the designated pole, junction box, or transformer. If further digging is required, MEC personnel will complete it. Any trenching within two feet of MEC facilities must be done by MEC qualified personnel. If any conductors or pipes are unexpectedly encountered while digging, leave them exposed. Refer to Figures 9 and 10 for trenching specifications. Keep the spoils pile at least 24 inches away from the edge of the trench. Refer to new OSHA (J) (2) requirements. (Place spoil on the side of the trench opposite the access route.) The bottom of the trench is to be flat. Schedule the trenching so the trench is open for the shortest practical time to avoid creating a public hazard and to minimize the possibility of the trench collapsing due to other construction activity, rain, etc. Prior to backfilling, the customer and MEC must jointly inspect the trench for adequate depth, conduit or cable placement, cable slack at termination points, and riser material. Pedestal stakes, property pins, and proper grade of facility shall be inspected by MEC and customer. If corrections are required, a second inspection will be necessary after the changes are completed. If needed, place four inches of clean bedding material at the bottom of the trench. Clean bedding material is defined as sand or clean soil with no solid material larger than one inch. Place the cable or conduit on top of this bed. Then cover the cable or conduit with a six-inch layer of clean bedding material. Compact the bedding material carefully, so the cable or conduit will not be damaged. MEC will determine the necessity for bedding on a case-by-case basis. The remainder of the trench is back-filled using available material. Pieces of scrap cable and other construction items must not be buried in the trench. Compact the soil, leaving a slight mound to allow for settling. Soil within 24 inches of poles, transformer pads, pedestals, and other facility points must be compacted mechanically by MEC. FIG. 9 - SINGLE USE TRENCH FOR MEC FACILITIES SEE OSHA RULES: KEEP EXCAVATED DIRT AT LEAST 24 FROM AN OPEN TRENCH DOME EARTH TO ALLOW FOR SETTLING INSTALLING CONDUCTORS IN A TRENCH When installing conductors in a trench, MEC will decide if it will be in conduit or direct-buried conductors. Conduit is required if the service line will cross under any permanent structure such as a driveway or sidewalk. MEC will make the final decision on all conduit requirements. DEPTH OF TRENCH MAX. PRIMARY 24 COVERAGE SECONDARY UNDISTURBED EARTH BACKFILL, FREE OF ROCKS AND DEBRIS 6 OVER 10 4 BENEATH CONDUIT OR DIRECT BURIAL CABLE TRENCH BOTTOM TO BE FLAT Page 12 New Service Handbook

13 JOINT-USE TRENCH The customer may place telephone, cable TV, or other electronic signal conductors in a trench with electric utility wires, providing the installation meets the requirements of these companies and their respective regulatory agencies and of MEC. In certain cases, gas pipes may be installed in a common trench (contact MEC) with a minimum of 12 inches of separation from all other lines. In no circumstances may water or sewer lines be installed in a common trench. See figure 10. Fig Joint Use Trench DOME EARTH TO ALLOW FOR SETTLING AS DESIGNATED BY MEC ENGINEERING DEPARTMENT SEE OSHA RULES: KEEP EXCAVATED DIRT AT LEAST 24 FROM AN OPEN TRENCH 24 UNDISTURBED EARTH 24 COVERAGE SECONDARY BACKFILL, FREE OF ROCKS AND DEBRIS DEPTH OF TRENCH MAX. PRIMARY 6 OVER 10 4 BENEATH TELEPHONE, CABLE TV 12 TRENCH BOTTOM TO BE FLAT CONDUIT OR DIRECT BURIAL CABLE DIRECT-BURIAL CONDUCTORS FOR PRIMARY VOLTAGE MEC personnel must carry out cable placement. If more than one cable is being placed in the trench, the telephone cable and cable TV lines must be separated at least 12 inches from the power line. Sufficient cable slack, never less than 24 inches, must be left in the trench at all risers, junction boxes and transformer pads. This slack prevents strain on the cable and terminals during backfilling, and allows for settling. After MEC inspection is complete, the consumer shall backfill the trench. MEC will connect the conductors at the meter end to the line (top) lugs of the meter socket. The customer is responsible for back-filling the trench and site restoration. MEC will energize the circuit after the customer completes back filling and compacting the trenches to the satisfaction of MEC. Missoula Electric Cooperative Page 13

14 UNDERGROUND CONDUIT MEC will install conduit to the meter socket, to MEC s pole, to the pad-mount transformer or junction box, to the radius that is prior to the meter base. The customer will install the radius and a slip joint at a customer-owned meter panel. Minimize the number of bends in the conduit. Bends must be a minimum of 36 radius unless otherwise shown on drawings. All bends must be factory-made. Runs longer than 200 feet or runs that contain multiple bends totaling 270 degrees or more must be approved by MEC before installation. Bends in runs of any distance must not total more than 270 degrees. If the conduit is more than 50 feet long, install a pull line capable of 500 pounds of tension in the conduit, with six feet of line extending from each end of the conduit. Install the pull line after the conduit is jointed and the glue is dry. Cap the conduit at both ends to keep it free of dirt and debris. After the electrical inspection is complete, backfill the trench, leaving open splice pits at both ends of the conduit. MEC will pull its conductors through the conduit, attach its wires to the line lugs at the meter socket, and splice the conductors at the point of delivery. The customer is responsible for back-filling the trench and site restoration. MEC will energize power after the customer completes back filling and compacting the trench to the satisfaction of MEC. CONDUIT SIZE The current rating of the service determines conduit size. Current Rating Single-Phase, 3-Wire Multi-Phase, 4-Wire 0 to 200 amps One 2-inch One 3-inch 201 to 400 amps One 3-inch One 4-inch 401 to 800 amps Two 4-inch Three 4-inch Over 800 amps MEC determines the conduit size If the conduit run is longer than 200 feet or has more than 270 degrees of bends, larger conduit than is listed may be required. For underground conduit, install electrical-grade Schedule 40 gray PVC. Refer to Figures 11, 12, and 13 (pages 12 & 13) for meter base installation. For underground conduit risers, install electrical grade Schedule 80 gray PVC. Refer to National Electrical Code: Article (D)(1) and Article Table refers to Cable Rating. CONDUIT AT THE SERVICE ENTRANCE MEC requires conduit be installed between the meter enclosure and the trench, per MEC requirements. The size of the conduit is determined by the current rating of the service. No bends are allowed in this riser. An expansion sleeve or slip-joint must be installed between the service panel and the termination of the conduit. The required method for bringing wires into the meter enclosure is: MEC wires enter through the bottom panel, at the left. Customer wires enter through the bottom panel at the right. If the conduit passes through pavement, a sleeve is required. Locate the sleeve and conduit away from the edge of the pavement, leaving some pavement intact next to the building. Conduit must be plumb and attached securely to the structure. Page 14 New Service Handbook

15 UNDERGROUND SERVICE, SURFACE-MOUNT METER Figure 11 shows a finished underground installation with the meter on the surface of a house. The customer is responsible for everything shown in Figure 11, except the meter. The service is underground from the meter on the building to a MEC conduit stub-out, handhole, or pad-mount transformer. After the customer installs the service equipment and obtains all inspections, MEC completes the installation of conductors, and then installs the meter in the meter socket. Fig # FELT BACKING METER SOCKET 200 AMP SOCKET JAW SLIP COUPLING ON 100/200 AMP EXTERNAL DISCONNECT LUGS FOR #1/0 THROUGH 250 MCM The service is underground from MEC conduit stub-out, junction box, or pad-mount transformer to the meter panel. After the customer installs the service equipment, and obtains an inspection, MEC completes the installation of conductors, and then MEC installs the meter in the meter socket. 2 GROUND RODS 6 APART 5 1/2 MAX. 4 STRAP 2 PVC CONDUIT SCHEDULE 80 FLEX PIPE SUPPLIED BY MEC Fig AMP SOCKET JAW 100/200 AMP EXTERNAL DISCONNECT UNDERGROUND SER- VICE, FLUSH-MOUNT METER (200-AMP OR LESS) 2 GROUND RODS 6 APART 5 1/2 MAX. 4 METER SOCKET ON LUGS FOR #1/0 THROUGH 250 MCM 2 PVC CONDUIT SCHEDULE 80 Figure 12 shows a finished underground installation with the meter mounted flush with the surface of the building. Flushmount meters are sometimes installed for aesthetic reasons. The customer is responsible for everything shown in Figure 12, except the meter. The service is underground from MEC conduit stub-out, junction box, or pad-mount transformer to the meter panel. After the customer installs the service equipment and obtains an inspection, MEC completes the installation of conductors, and then MEC installs the meter in the meter socket. Missoula Electric Cooperative Page 15

16 UNDERGROUND SERVICE, PEDESTAL METER (PROVIDED BY MEC) A meter pedestal is a freestanding structure that supports service equipment for underground service and is provided by and owned by MEC. See Fig. 13. Fig AMP METER SOCKET MEC shall not install an underground meter pedestal more than 200 feet from the last power supply point, i.e. transformer or secondary junction box. Any exceptions must be approved by MEC. The meter pedestal shall contain the disconnect switch required by the NEC. UNDERGROUND SERVICE, METER POST TEM- PORARY POWER (PROVIDED BY CONSUMER) 4 MIN ON 200 OFF FACTORY BUILT METER PEDESTAL DISCONNECT (CUSTOMER-OWNED) Figure 14 shows a finished installation for temporary service, using a meter post. The service is underground from MEC conduit stub-out, hand-hole, or pad-mount transformer. The customer provides everything shown in Figure 14, except the meter and the service line. Fig. 14 TEMP SERVICE MUST BE WITHIN 5 OF JUNCTION BOX OR PADMOUNT TRANSFORMER. 24 MIN 2 GROUND RODS 6 APART MIN TOP OF METER BELOW TOP OF STRUCTURE. METER SOCKET, DISCONNECT AND DISTRIBUTION PANEL. PRESSURE-TREATED WOOD POST 4 X 4 (CONTINUOUS SINGLE STRUCTURE). 2 X 4 BRACING (FROM 2 DIRECTIONS AS REQUIRED). MEC SERVICE LINE ELBOW 90º BEND 24 MIN RADIUS CUSTOMER-OWNED SERVICE LINE GROUND WIRE CONDUIT SECURELY FASTENED TO POST. 5.5 MAX. 4 FIRMLY TAMP EARTH AROUND POST. DOME EARTH TO ALLOW FOR SETTLING. SAFETY CLEARANCES AROUND TRANSFORMERS Clearances from pad-mount transformers to structures are measured from the nearest metal portion of the transformer to the building structure or any overhang. The clearance from a building is three feet if the building has non-combustible walls (brick, concrete, steel, or stone) and ten feet if the building has combustible walls (including stucco). A ten foot clear zone shall be maintained in front of equipment for access. MEC STUBOUT, HANDHOLE OR TRANSFORMER. 5 MAX GROUND RODS 6 APART Other clearances are shown in Figure 15. These clearances also apply to any oil-filled electrical equipment. TRANSFORMER INSTALLATIONS MEC is responsible for installing the pad-mount transformer at the customer s site. Conductors to the primary side of the pad-mount transformer enter at the left side of the transformer. Conductors to the secondary side enter at the right. The trench runs from the right side of the pad-mount transformer to the customer s building. Fig. 15 SWIMMING POOL PADMOUNT TRANSFORMER WINDOW, VENT OR OTHER OPENING PADMOUNT TRANSFORMER 3 10 GAS METER BUILDING FIRE ESCAPE MEC is responsible for installing the service conductors in the trench from the pad-mount transformer to the service entrance equipment. 6 PADMOUNT TRANSFORMER 20 FUEL TANK Page 16 New Service Handbook

17 WORK CLEARANCES AROUND TRANSFORMERS A minimum clearance of ten feet of clear, level working space is required in front of a pad-mount transformer to allow use of hot sticks. Other clearances are shown in Figures 16 and 17. All these clearances apply to any oil-filled electrical equipment. Landscaping and other obstructions must not encroach on these clearances. GUARD POSTS Fig TOP VIEW PADMOUNT TRANSFORMER 10 It is the customer s responsibility to install and maintain guard posts where MEC equipment is exposed to vehicular traffic. Guard posts are also required where minimum clearances around equipment cannot be met. If the post is placed in stable soil, surround it with six inches of concrete. If the soil is unstable or sand, surround the post with 12 inches of concrete. Fig COOLING FINS ACESS DOORS If several guard posts are used, locate them no more than five feet apart. For extra visibility, paint the guard posts traffic yellow Commercial areas exposed to large service type trucks require a six-inch diameter post, not the four inch postillustrated in Figure TOP VIEW VAULT LID 3 Work clearances around an underground splice box. Fig. 18 COCRETE DOMED TOP DIAMETER SCHEDULE 40 GALVANIZED STEEL PIPE FINAL GRADE Example: MEC equipment exposed to vehicular traffic 2 6 CONCRETE 6 MINIMUM CONCRETE SURROUNDING POST Missoula Electric Cooperative Page 17

18 ANSI - American National Standards Institute. An independent administrator and coordinator of voluntary industry standards. Bypass - A device which shunts current around the socket, so the meter can be removed without interrupting service. Clearance - A specified minimum distance between two objects to assure adequate space for safety, security, or access. Common Ground Point - The point where the grounding electrode connects to the equipment-grounding conductor and/or the circuit-grounding conductor. Conduit - A pipe with a smooth interior surface for easy drawing-in of electrical conductors. Conduit may be metallic or nonmetallic. Corrosion Inhibitor - An electrical joint compound used to retard oxidation at electrical connections. Current Transformer (CT) - A transformer whose secondary current is a precise fraction of its primary current. Using current transformers, high-current circuits can be measured with conventional meters. Demand - The average rate at which energy (kilowatthours) is consumed, during a specified interval of time. Direct-Burial Cable - Cable which may be safely installed in the ground without the protection of a conduit. Direct-Connect Meter - A meter which carries full load current and connects across full line voltage. Also called a selfcontained meter. Drip Loop - A downward loop in the customer s conductors, near where the customer s conductors attach to the power company s overhead conductors, to prevent water from entering the service mast at the weather-head. EUSERC - Electric Utility Service Equipment Requirements Committee. Fault - A partial or total failure of insulation which causes a short circuit between conductors, or between a conductor and ground, causing an abnormal current to flow. Also, a failure (break) in a conductor which causes an open circuit. Fault Current - A current, which flows between conductors, or between a conductor and ground, due to an abnormal connection between the two. A fault current flowing to ground may be called a ground fault current. Guy - A cable or brace that supports a mast or pole. High Leg - In a four-wire delta service, the phase with a voltage higher than the other two phases. Also called wild leg, delta leg. Instrument Transformer - A transformer, which delivers as its output, a precise fraction of the input line current or line voltage. Instrument transformers allow standard meters to measure high currents and voltages. GLOSSARY Instrument-Rated Meter - A meter used in conjunction with instrument transformers to measure high-voltage or highcurrent services. Also called a transformer-rated meter. Line Conductor - A service conductor installed by the electric utility, to the meter. Load Conductor - A service conductor to the customer s load connected to the load side of the meter. Load Side - The company-owned side of electric service. See the glossary entry for point of delivery. Line Side- The customer-owned side of the electric service. See the glossary entry for point of delivery. Manual Link Bypass - Provision for manually installing conductive links between the line and load terminals in the meter socket. These links maintain electrical service to the customer when the meter is removed. Also called manual circuit-closing block. Manufactured Home - A factory-assembled structure built on a permanent chassis, transportable in one or more sections, and designed to be used as a dwelling with a permanent foundation. Also called a modular home. New electric service to a manufactured home has the same requirements as installing new service to a permanent single-family residence. MEC - Missoula Electric Cooperative, Inc. Meter - The first physical device located on the customer s side of the point of delivery, the customer uses the meter to measure the electric power usage. Although located on the customer side of the point of delivery, the power company owns the meter. Meter Jaw - A spring-loaded receptacle inside a meter socket, which captures the terminals (blades) of a meter, and connects the meter terminals to the service conductors. Meter Pedestal - A factory-built assembly containing a meter socket and disconnect switches. Meter Ring - A metal ring, which secures the meter to the meter socket, which can be sealed by the electric utility to prevent tampering with the meter. Meter Socket - the mounting device consisting of meter jaws, connectors, and enclosure for receiving a socket-type meter. Mobile Home - A factory-assembled structure built on a permanent chassis, transportable in one or more sections, and designed to be used as a dwelling without a permanent foundation. A meter pole provides overhead service to a mobile home. A meter pedestal provides underground service to a mobile home. NEC - National Electrical Code. National regulations for the installation of electrical equipment inside buildings. Published by the National Fire Protection Association. NEC rules apply to equipment on the customer s side of the point of delivery. Page 18 New Service Handbook

19 NEMA - National Electrical Manufacturers Association. A trade association which publishes standards for manufacturers of electrical equipment, including enclosures and racks. NESC - National Electrical Safety Code. National regulations for the installation, operation, and maintenance of electric supply and communication lines. Published by Institute of Electrical and Electronics Engineers. NESC rules apply to equipment on the electric utility s side of the point of delivery. NFGC - National Fuel Gas Code. Neutral - The grounded conductor in a single-phase three-wire, or three-phase four-wire system. OSHA - Occupational Safety & Health Administration Point of Attachment - The point at which MEC service conductors are mechanically attached to the customer s premises. For overhead services, the point of attachment is usually an insulated clevis. Point of Delivery - The ownership boundary point in the electrical service between the power company and the customer. Technically, the meter is located on the customer s side of the point of delivery although the power company owns the meter. The company-owned side is often referred to as the line side of the meter. The customer-owned side is often referred to as the load side of the meter. Power Factor - Technically, the cosine of the phase angle between the circuit voltage and current waveforms. Since phase angles are difficult to measure, measuring power or impedance usually derives power factor. Power factor is the ratio of active power to apparent power (watts divided by volt-amperes). Power factor has no units, but is commonly expressed as a percentage. For example, if active power is 96 kw and apparent power is 100 kw, the power factor is 96%. Primary Voltage - The voltage at which electricity is delivered from substations to distribution transformers. Primary voltage is greater than 600 volts. Raceway - An enclosed channel for holding wires or cables. If designated for line conductors, the raceway must be able to be sealed. The intermixing of line and load conductors in the same raceway is not permitted. Seal - A locking device to secure a meter or other service equipment. Secondary Voltage - The voltage at which electricity is delivered from distribution transformers to customers. Secondary voltage is less than 600 volts. Select Backfill - Soil or sand free from sharp objects, rocks, scrap building material, and corrosive material. Self-Contained Meter - A meter which carries full load current and connects directly across full line voltage. Also called a direct-connect meter. Service Drop - For overhead service, the power company s service line between the distribution transformer and the point of delivery. Service Line - Conductors from the distribution transformer to the customer s point of delivery. See service drop, service lateral. Service Entrance Equipment - The service equipment, which is supplied by the customer, namely, conduit, conductors, mast, weather-head, meter base, enclosures, disconnects, and panels. Service Lateral - For underground service, the service line between the distribution transformer and the point of delivery. Service Mast - For overhead service, the conduit rising above the meter to provide mechanical protection to the customer s conductors and to support the service drops from the power company. Socket - The mounting device for socket meters. Includes spring-loaded meter jaws, connectors for line and load conductors, and an enclosure. Temporary Service - Electric service provided by the power company during the construction phase of a project. Test Switch - A device used to isolate connections to a meter from the meter s instrument transformers. Transformer-Rated Meter - A meter used in conjunction with instrument transformers, to measure high-voltage or high-current services. Also called an instrument-rated meter. UL - Underwriters Laboratories. An independent product-testing and certification organization. Voltage Transformer - (VT, or PT for potential transformer) A transformer whose secondary voltage is a precise fraction of its primary voltage. Using voltage transformers, high-voltage circuits can be measured with conventional meters. Missoula Electric Cooperative Page 19

20 1700 W. Broadway Missoula, MT Ph Fax R