REQUIREMENTS AND SPECIFICATIONS FOR HIGH VOLTAGE CUSTOMER BUILT FACILITIES PEPCO ENGINEERING

Transcription

1 REQUIREMENTS AND SPECIFICATIONS FOR HIGH VOLTAGE CUSTOMER BUILT FACILITIES PEPCO ENGINEERING Revised October, 2013

2 TABLE OF CONTENTS 1.0 INTRODUCTION REQUIRED DRAWINGS Site Plan Conduit Drawings Customer Vault Switchgear Drawings Customer Building Load PERMITS AND REGULATIONS Private Property Public Space CONDUIT AND MANHOLES Type of Conduit Conduit Layout Duct Configuration and Trench Depth Ductbank Stubs Manholes Manhole Roof Sealing Ductbank Padmounted Switch Pads Inspection and Certification Conduit into Customer Vaults SWITCHES AND CABLES Customer Vault Supply Cable Termination Cable Entrance to Switchgear Grounding Access and Switch Requirements CONTACT PERSONNEL INDEX OF REFERENCE DRAWINGS

3 1.0 INTRODUCTION The following requirements and specifications are provided for the customer to insure that the design approval and construction of new or renovated customer owned facilities will meet the standards of design and construction as set forth by Pepco. In the District of Columbia and Maryland, the customer is responsible for installing and maintaining structural facilities such as poles, conduit, pads, and manholes on private property that are required to support or protect Pepco cables and equipment. Pepco will install, own, and maintain all cable and switches on the line side of the service equipment. In all customer construction activities, it is the customer s responsibility to follow and to comply with all federal, state, and local construction safety codes and regulations. Before starting any excavation, call Miss Utility at , 48 hours minimum in advance to locate all underground facilities. The customer is responsible for the cost of all repairs in the event of damages to the existing facilities. While manhole covers and frames must be purchased from Pepco, some other construction materials may also be procured from Pepco. Pepco representatives can provide a list of available items. All material used to protect Pepco facilities must be approved by Pepco prior to construction. This specification references only 13kV underground installations. High voltage services other than 13kV underground (4kv, 13kV OH, 34kV, 69kV, etc.) will be handled on a case by case basis due to the limited number of these types of services. 2.0 REQUIRED DRAWINGS 2.1 Site Plan All existing and proposed buildings, right-of-way lines, property lines, streets (named), existing and proposed utilities, driveways and grass spaces are to be shown. The aforementioned items shall be submitted on a 1 = 30 or larger scaled drawing. PEPCO will provide, upon request, sketches showing the preferred location of the customer conduit stub to be picked up by PEPCO. 2.2 Conduit Drawings Plan view drawings of existing and proposed customer built conduit, manholes and nearby existing facilities will be submitted to PEPCO for approval and comments. Drawings, in 1 = 20 or larger scale, should include details of concrete encased conduit, size and orientation of proposed manholes, location of manholes (roadway or sidewalk), sump pit in manhole, duct entrance recess, roof type, location of switch manholes or padmount switch locations, radius of conduit bends, and any additional information that would enhance the understanding of the drawing. Conduit dimensions should be shown from wall to wall. One switch hole per two feeders or one padmount switch pad per feeder is required. These drawings will be used to inspect and certify customer built facilities. 2.3 Customer Vault Plan and elevation scale drawings of the customer vault should include existing and/or proposed switchgear, location of duct entrance into the vault, cable pulling eyes, clearance around switchgear, cable tray layout, and means of personnel entrance into the customer vault. Refer to Civil and Substation Engineering, Guide Specification for Metal-Clad Switchgear for Customer Substations, SPEC. NO. SEGS 051 for more details. 2.4 Switchgear Drawings The high voltage termination cabinet is to be shown dimensioned or scaled. Cable entrance into the switchgear (top or bottom), clearance between phase bus, ground bus, cable supports and internal dimensions are to be shown. Control cables are not permitted to be attached adjacent to incoming supply cables. 3

4 2.5 Customer Building Load The customer shall provide proposed building loads including future expansions to PEPCO for review. 3.0 PERMITS AND REGULATIONS 3.1 Private Property The customer is responsible for obtaining all permits, rights-of-way, and easements for construction on private property. 3.2 Public Space Pepco will prepare construction drawings and apply for any permits that are required for construction in public space. Pepco s engineering work and permit application will begin upon receipt of approved customer site plan and conduit drawings from the customer. Pepco s construction is contingent upon receiving all required permits. 4.0 CONDUIT AND MANHOLES 4.1 Type of Conduit Conduit shall be 5-inch diameter, Iron-Pipe-Size (IPS) fiberglass reinforced epoxy (FRE) conduit manufactured in accordance with NEMA TC14A, latest revision. 4.2 Conduit Layout Conduit lines shall be designed to minimize the number of bends required. Where bends are necessary, a minimum bending radius of 12 feet will be used. Exceptions to this radius will occur at bottom-fed switchgear and terminations at an overhead pole. At these locations, a minimum 48 inches bending radius will be allowed. Conduit lines shall not turn more than 180 degrees between pulling locations and the design distance between manholes shall be 600 feet or less. 4.3 Duct Configuration and Trench Depth Duct configuration shall be as shown on Pepco Standard drawing and installed in the Buildup method as in drawing Trench depth shall be deep enough to maintain a minimum cover of 36 over the top of the ducts. All ducts are to be encased to the thickness as specified in drawing If transforming the duct configuration is needed, the ducts must be arranged in the manner as shown on drawing The concrete for conduit encasement is to have a minimum compressive strength of 3000 psi, non-air entrained with pea gravel, at 28 days. No concrete pouring is allowed when the temperature is lower than 40 o F or higher than 90 o F without special provisions to the concrete mix design. 4.4 Ductbank Stubs The ductbank shall slope away from the customer vault to the property line or first manhole to prevent water migration into the building. The customer shall terminate the ductbank two feet outside of the property line for Pepco to pick up. Each duct shall end with a coupling or flared bell end for Pepco to attach conduit. The stub must be plugged to prevent dirt and debris from entering into the conduit prior to Pepco connection. A marker or stake shall be placed to locate the duct. The customer is responsible for locating the conduit stub if the marker is lost. 4.5 Manholes Two manhole sizes will be built: (A) Line holes, for splicing, will be 6 X 12 with 7.0 minimum clear depth; (B) Switch holes will be 6 X 14 with 10 minimum clear depth with removable roof slabs. Manholes dimensions are inside dimensions. Precast manholes will be from an approved Pepco supplier. 4

5 One switch hole per two feeders may be required (see Section 5.5). Switch manhole must be located in a sidewalk or grassy area accessible by PEPCO 24 hours a day. Manhole recesses will be built at each duct entrance. Ducts will enter the manhole on the 6 wall on center line. Manholes should be spaced at approximately 600 intervals starting at the property line and working towards the customer vault. Sump pump pit will be required in each manhole. Pulling eyes are required in each manhole (5000 pound capacity minimum). Eyes are to be located in the wall, one near the ceiling and one near the floor, opposite each ductbank entering the manhole. A ground rod (5/8 diameter, 8 long, copperweld) at the corner of the sump pit must be installed in each manhole. This ground rod is to be connected to the manhole steel rebars as shown in drawing Depending on the surface condition, sidewalk or roadway, the distance between the manhole inside ceiling and the surface shall be 21 minimum for recessed roadway roof, 18 minimum for recessed sidewalk roof, 9 minimum for flush roadway roof, and 6 minimum for flush sidewalk roof. The concrete for the manhole construction (manhole floor, walls and roof) is to have a minimum compressive strength of 4000 psi at 28 days. No concrete pouring when the temperature is lower than 40 o F or higher than 90 o F without special provisions in the concrete mix design. Precast manholes are permitted only from a Pepco approved supplier. 4.6 Manhole Roof Two types of manhole roofs are used. For manhole placed in areas subject to vehicular traffic, a roadway type roof is required. Only line holes shall be built in roadways. A sidewalk type roof will be used on both line holes and switch holes located in a sidewalk or grass area. The switch hole must be equipped with a removable roof. Each manhole must have two access openings. Manhole frames and covers must be purchased from PEPCO. Refer to the PEPCO manhole standard drawings for associated drawing numbers for manhole roofs, slabs, frames, and covers. 4.7 Sealing Ductbank The customer is responsible for sealing and waterproofing conduit which enters the customer s building or vault. Sealing the ducts is to be completed after the cable has been installed. The common materials to be used for sealing are Dux Seal and Okum. First the Okum is to be frayed by twisting and shaking, and then placed around each conductor in a manner that isolates all conductors from each other and from the duct walls. The Okum is pushed into the duct until a tight seal is obtained and all voids are filled on all surfaces. The total length of the duct to be filled with Okum is 5 inches. The Okum is to be pushed back far enough to leave 5 more inches for inserting the Dux Seal. The Dux Seal shall be installed in the same manner, isolating and covering all conductor and duct surfaces. The Dux Seal shall be flush with the duct ends. Extra care must be employed to prevent damages to the cable insulation when pushing and driving the sealing materials. When sealing empty ducts, duct plugs should be used to plug the duct ends and covered with an abundance of Dux Seal on the top. Any other sealing method shall be submitted to PEPCO for approval. In case of severe water conditions, contact PEPCO for procedures to waterproof the manhole. 4.8 Padmounted Switch Pads A concrete box pad to accept a padmounted switch may be required in specific cases. The box pad will replace the 6 X 14 switch hole. One box pad will be required per feeder. PEPCO will notify the 5

6 customer when a padmounted will be used in lieu of the underground switch. The standard drawing and for the box pad is attached. 4.9 Inspection and Certification All conduit and manhole construction is subject to inspection and approval by PEPCO. Conduit and manholes must be inspected prior to pouring concrete for encasement or manhole structure and then again prior to backfill the excavation. All ducts must be certified by pulling a mandrel ½ smaller than the duct diameter through each duct. In addition to pulling the mandrel, a pulling line shall be installed in each duct to be used for cable pulling Conduit into Customer Vaults Customer switchgear is supplied in two different ways. The first is bottom-fed, which requires two ducts per feeder to be built and turned up into the bottom of the line side high voltage termination cabinet. The radius of the bend into the switchgear will be a minimum of 48. The ducts are to extend 2 above the switchgear floor to prevent chafing of the cable. The duct openings shall be plugged before and sealed after the cable installation. The second type is top-fed switchgear. Conduit will enter the vault and cable trays will be built from the inside wall of the customer vault to the switch gear. Cable tray drawings must be submitted and approved by PEPCO. Refer to standard drawings HVS-002 and HVS-003 for required parameters. 5.0 SWITCHES AND CABLES 5.1 Customer Vault Supply Customer built vaults will be supplied with 13.2KV feeders. Each feeder will be switched outside the customer vault. PEPCO will install the switches and cable in the customer built conduit and manholes and into the switchgear. The customer is responsible at their expense for supplying any ladders and scaffolding as required by Pepco Construction forces, to provide crews access to cable trays or other equipment, in all vaults and switchgear rooms in excess of 6 feet in height. Please consult with the Pepco Construction supervisor during any pre-construction walk-throughs to ensure adequate facilities will exist to allow Pepco to perform their work. 5.2 Cable Termination The cable will be three single conductor, 1/10 or 600KCM EPR cable. Cable terminations will be made with stress cone type terminators. The customer will supply a phase bus that will accept a 2- hole NEMA connector. Refer to Civil and Substation Engineering guide specifications for additional requirements. PEPCO will inspect the switchgear prior to connections and energization. 5.3 Cable Entrance to Switchgear Cable pulling eyes (5,000 pound capacity) are to be mounted above each incoming feeder cubicle. Pulling eyes are required for both top and bottom-fed switchgear. An additional pulling eye is required for top-fed switchgear on the ceiling at the end of the switchgear line opposite the duct entrance. 5.4 Grounding A ground bus will be provided inside the high voltage cabinet for PEPCO to attach the system ground. The ground bus will be drilled to accept a two hole NEMA hylug (5/8 hole). 5.6 Access and Switch Requirements In government installations where security clearance for PEPCO personnel is not required and in Government and private property installation where 24 hour access for PEPCO personnel is guaranteed, externally accessible disconnecting and grounding switches may not be required. Where security clearance may be required for access by PEPCO personnel to the customer switchgear or where 24 hour access to switchgear by PEPCO personnel cannot be guaranteed, additional manholes with removable sidewalk type roofs and conduit will be required to accommodate externally accessible PEPCO disconnecting and grounding switches for each supply feeder. 6

7 6.0 CONTACT PERSONNEL Pepco Engineering AREA CONTACT Washington DC Engineering Associate Southwest & Northwest 3400 Benning Road Maryland Washington D.C Montgomery County Mail Stop 2B59FF Washington DC Engineering Associate Southeast & Northeast 3400 Benning Road Maryland Washington D.C Prince Georges County Mail Stop 2B59FF

8 7.0 INDEX OF REFERENCE DRAWINGS DRAWING # # OF SHEETS REV. DATE TITLE /20/2010 CABLE PULLING-IN IRON /29/ X 14-0 MANHOLE /29/ x 12 MANHOLE /21/ MANHOLE COVER /11/ MANHOLE COVER FRAME ROADWAY TYPE /29/ /29/ /10/2008 BUILT-UP METHOD FOR FIBERGLASS AND PVC CONDUIT PRECAST CONCRETE COLLAR FOR U.G. TO O.H. CONNECTION METHOD OF INSTALLING MANHOLE FRAME & COVERS /29/2008 PVC & FIBERGLASS CONCRETE ENCASEMENT /1/2008 POLE RISER SHIELD U.G. TO O.H. CONNECTION /25/2011 MANHOLE RECESS /15/2008 SUMP PIT FOR STANDARD MANHOLE /15/2008 GROUNDING FOR STANDARD MANHOLE /15/ /09/ /09/ /09/ /11/ /13/ /29/2008 DRAINAGE DUCT BETWEEN ADJACENT MANHOLES DUCT TRANSPOSITION SEQUENCE AND SPACER REQUIREMENTS PRECAST ROADWAY ROOF FOR 6 X 6 MANHOLE PRECAST ROADWAY ROOF FOR 6-0 X 8-0 MANHOLE FRAMES FOR FLUSH TYPE MANHOLE FOR SIDEWALK AND ROADWAY BOX PAD INSTALLATION FOR 13KV PADMOUNTED 3-WAY GANG SWITCH BOX PAD FOR 13KV PADMOUNTED OIL SWITCH 8

9 /15/ /15/2008 HVS /27/ X 6-10 FLUSH TYPE ROOF SLABS FOR SIDEWALK MANHOLES SPACERS FOR SDWK AND RDWY MH REMOVABLE ROOFS TYPICAL CUSTOMER-BUILT MANHOLE AND CONDUIT HVS /27/2012 CUSTOMER-BUILT BOTTOM-FED SWITCHGEAR HVS /27/2012 CUSTOMER-BUILT TOP-FED SWITCHGEAR CE /27/2012 WALL TIE FOR SUPPORT BEAM 9

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