Section 13 — Electrical

Electric Bus Duct 480 Volt and Higher

IPE Engineering Practice IPE-EP-13-24-1

Document number: IPE-EP-13-24-1 · Section: 13 — Electrical

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1.1

1.2

1.3

1.4

1.5

2.0

3.0

3.1

3.2

3.3

3.4

3.5

SCOPE

This Practice, including the Bus Duct 480 Volt and Higher Data Sheet, EP 13–24–1DS, covers requirements for assemblies of indoor and outdoor bus duct rated 480 Volt to 38 KV, 3 phase, 60 HZ for application on low resistance, high resistance, solidly grounded, or ungrounded systems, as specified on the Data Sheet. Bus duct shall conform to this Practice, unless written approval is obtained from IPE for exceptions.

This Practice is appropriate for attachment to an inquiry or purchase document when accompanied by the referenced IPE Engineering Practices and completed Data Sheets.

A revision bar indicates all changes made to this Revision.

Any deviation from this practice must be approved by the procedure described in EP 1–1–3.

An asterisk (*) indicates that a decision by the Owner’s Engineer or Owner is required, or that additional information is to be furnished by the Purchaser.

REFERENCES

The latest edition of the following standards and publications are referred to herein.

STANDARDS AND PUBLICATIONS

DEFINITIONS

Contractor – Company or business that agrees to furnish materials or perform specified services at a specified price and/or rate to the Owner.

Inspector – A Inflection Point Engineering, LLC appointed engineer or inspector.

Manufacturer – The recipient of a direct or indirect purchase order for materials and/or equipment. In this context, a direct order is one issued to a Manufacturer by a Contractor or the Owner. An indirect order is one issued to a Manufacturer by a vendor (recipient of a direct order) for materials, fabricated components, or subassemblies.

Owner – Inflection Point Engineering, LLC.

Owner’s Engineer – A Inflection Point Engineering, LLC appointed engineer.

3.6 Purchaser – The party placing a direct purchase order. The Purchaser is the Owner’s designated representative.

4.0 SERVICE CONDITIONS

(*) Bus duct assemblies shall perform satisfactorily when installed and operated indoors or outdoors either intermittently or continuously in an atmosphere typical of petrochemical facilities. Unless otherwise noted, bus duct assemblies shall be suitable for use in a 104oF maximum ambient, -22oF minimum ambient, and at an altitude of 3,000 feet or lower.

DESIGN, CONSTRUCTION AND MATERIALS

• Basic Design/Construction
• The bus duct design and performance shall comply with ANSI C37.23, NFPA 70 and the requirements of this Practice.
• All bus ducts shall be of the non-segregated type. The bus conductors shall be supported and spaced so there is air separation between buses of different phases and between all buses and the enclosure.
• Provisions shall be made for expansion and contraction of the bus conductors and the enclosure due to ambient temperature and changes resulting from load and short circuit currents.
• (*) The bus duct Manufacturer shall provide all the necessary flexible copper connectors to connect the bus duct to the line/load assemblies. Note: Insulated power cable is not an acceptable ”flexible connector” and shall not be used for this purpose. All bus duct connections shall be fully rated for the current specified on the Data Sheet.
• Systems with resistance grounding, see Data Sheet, shall have the bus insulators and sleeves rated for full line to line voltage rather than line to ground voltage.
• Power Bus
• Bus duct power buses shall be copper with tin–plated joints.
• Buses shall be completely insulated (fully clad) with a flame retardant, non-hygroscopic, high dielectric insulation material.
• All joints and terminations shall be insulated using taping and/or insulating booting that is flame retardant, non-hygroscopic, high dielectric insulation.
• All outdoor power bus bars shall be supported with non-hygroscopic, track resistant, high strength porcelain sleeves and supports. Indoor bus duct rated higher than 15 KV shall be supported with porcelain sleeves and supports same as outdoor assemblies.
• Indoor bus duct rated 15 KV and lower shall use either porcelain sleeves and supports as in Paragraph 5.2.4 above and/or non-hygroscopic, track resistant, cycloaliphatic epoxy sleeves and supports.
• (*) Buses shall be mechanically braced for the short circuit ratings specified on the Data Sheets. Normally this shall be the withstand/close and latch rating of the connected equipment.
• Bus duct shall be designed for the basic insulation level (BIL) in Table 1.

• Enclosure and Termination Boxes
• General
• It is preferred that the bus enclosure be fabricated from painted aluminum. The use of ferrous magnetic housing materials such as steel shall be avoided. Aluminum housings shall be

1/8 inch or thicker material throughout.

• The enclosures of bus duct assemblies shall provide an electrically continuous path from supply to load end. The assembled enclosure shall be capable of safely conducting the maximum phase to ground fault current available for a minimum of two seconds. All enclosure joints shall be designed to form a low resistance electrical bond between bus duct sections and at terminations. Any non-conductive coatings, such as paint, shall be removed or penetrated to ensure a good electrical contact.
• Enclosures shall be provided with an external ground pad with facilities to accommodate a two hole compression lug for connection of the Owner’s #2/0 AWG stranded copper ground wire. A pad shall be provided at each end of the bus duct enclosure.
• Outdoor Bus Duct

In addition to the requirements of 5.2.1, outdoor sections of bus duct shall comply with and/or include the following:

• The power buses shall be completely enclosed with a weatherproof, corrosion resistant metal enclosure.
• The enclosure shall be provided with thermostatically controlled space heaters to prevent condensation.
• Drain openings/devices shall be provided to remove condensation (remove accumulated moisture) from the low points of outdoor bus runs. Drain openings shall be screened or otherwise made vermin proof.
• Bus duct having sections inside and outside a building/shelter shall have a flame resistant, non-hygroscopic, non-conductive barrier in the bus duct at the building wall to prevent condensation between sections.
• All hardware exposed to the weather shall be stainless steel.
• All housing and cover flanges shall be gasketed with non-corrosive material and shall be completely concealed for protection against deterioration.
• Top covers shall be crowned/sloped to shed rain.
• Indoor Bus Duct

In addition to 5.2.1 and 5.2.2, indoor sections of bus ducts may have ventilated enclosures. Ventilated enclosures shall meet the following additional requirements:

• Ventilating openings shall be of a size or guarded to prevent the entrance of a 1/4 inch diameter probe.
• Ventilating openings shall not be located in the top side of the enclosure.
• Painting
• The paint process shall be the Manufacturer’s standard which will result in a minimum of 3 mills thickness of finish coat paint.
• Color to be a light gray similar to ANSI 61.
• Space Heaters

• Space Heater Wiring
• Space heaters shall be completely factory wired with no exposed wires inside the bus housing.
• Space heater wire to be 600 V, stranded copper with SIS, XHHW or XHHW–2 insulation.
• Heater wiring splices and termination shall be via terminal strips and wires having insulated barrel, compression type spade lug terminations. Wire nuts are unacceptable.
• (*) Heater wiring shall be one of the methods described below as identified on the Data Sheet.
• Terminated in a cast metal junction box at the designated end of the bus duct housing. The cast box shall have a 3/4 inch threaded opening for Owner’s RGS conduit.
• Provided with a three foot coiled extension for connection to the Owner’s power source.
• Space Heater Controls and Other
• Space heater shall be thermostatically controlled.
• The thermostat shall be adjustable from outside the bus duct. The thermostat shall be designed/located for easy removal without requiring opening of the bus housing.
• Space heaters shall be rated at 240 VAC and operated at 120 VAC to maintain a lower heater surface temperature.
• Space heaters shall be located/designed for easy removal without requiring opening of the bus housing.
• The space heaters shall be mounted in a manner such that moisture inside the bus duct will not run down on the heater or submerge the heater.
• All space heater components shall be suitable for the specified area classification.
• Nameplates
• Nameplates shall be provided to identify space heater and thermostat locations.
• Each complete bus duct assembly shall be provided with a stainless steel nameplate fastened to the bus duct with screws. The nameplate shall have as a minimum, all the information required in NFPA 70 (NEC) Paragraph 364-21.

TESTING

• (*) The Manufacturer shall perform all tests at the Manufacturer’s facility, unless directed otherwise by the Owner.
• Testing shall be permitted on completely assembled bus duct sections. Each section shall be tested.
• Testing shall include the following:
• ANSI C37.23 test as follows:

Paragraph 6.2.1.1 rated frequency withstand test.

• Polarization Index Test
• 480 volt bus duct use 1000 volt test instrument
• For bus duct rated 2.4 KV and higher use a 2500 volt or higher test instrument.
• Witness Testing

(*) When witness testing is specified, the Owner shall witness the complete testing of all items outlined in Section 6.0.

DRAWINGS AND DATA REQUIREMENTS

(*) All drawings provided for this equipment shall show equipment as specified and ordered. Typical drawings are not acceptable, unless they are revised to show only the equipment being furnished. Drawings shall be supplied in the quantities and the format shown on the Data Sheet.

• Information to be Supplied with Quotation
• Specific listing of any exceptions to those requirements specified.
• Equipment or features included but not necessarily specified.
• Sketches showing equipment layout/orientation with dimensions.
• Provide information on support requirements for bus duct runs. This information shall be provided at the time of quotation and shall include weights, moments, expected expansion, maximum deflections, and recommended support locations.
• Include unit costs for add/delete per linear foot and for 90 degree ells.
• Number of days of field service allowed (when specified) and cost per day.
• Complete lists and descriptive data of all equipment and accessories proposed shall be included and any components not manufactured by the Seller submitting the proposal shall be so noted as well as the Manufacturer and type proposed.
• Priced lists of normal recommended spare parts for the specified equipment shall be included in the quotation.
• Quote must be for equipment as specified, including any requested alternatives. Manufacturer recommended alternatives shall be provided with associated adds/deducts.
• Itemized list of unassembled equipment.
• Cost for witness testing, if specified.
• Information to be Submitted to Owner Approval after Receipt of Order
• Complete structural drawings showing:
• Arrangement and layouts.
• Dimensional plan and elevation.
• Conduit entrance locations and dimensions.
• Bus bar locations and configurations.
• Line and load termination dimensions and configuration.
• Purchaser’s wiring terminal block locations, and all other terminal block locations.
• Identify all items that will require field assembly.
• Grounding connections.
• Information requested.
• Complete Bill of Materials for all assembly parts.
• All flange dimensions at load/line terminals.
• Detailed connection (wiring) diagrams showing:

• All wiring within each unit.
• All interconnecting wiring between units.
• Identification of all terminal blocks.
• Clear identification, by some distinguishing method, of all wiring that is to be installed by the Owner. This shall include spare auxiliary contacts and relay contacts which shall be wired to terminal blocks for future use.
• Detailed listing of all nameplates with nameplate information.
• Certified Information to be Supplied
• All information requested in Paragraph 7.2.
• Installation, maintenance, and operating instructions: Installation and operating instructions shall cover all the equipment furnished. This shall also include field testing (e.g. D.C. high potential test voltage allowed, splice resistance, etc.)
• Material List: A material list shall be furnished listing the quantity, rating, type and manufacturer’s catalog number of all equipment.
• Test reports for testing outlined in Section 6.3.
• Spare parts listing.

SPARE PARTS

A complete priced spare parts recommendation based on the total purchase order is required within 60 days after the Manufacturer receives the purchase order. Spare parts recommendations shall include:

• A complete spare parts list, including parts location diagrams or drawings.
• Lists of priced spare parts as recommended by the Manufacturer to be on hand during plant start-up and the first year’s operation.

SHIPPING

• (*) “Preparation for Shipment” shall be in accordance with Manufacturer’s standard, unless otherwise noted on the ”Request for Quotation” and/or Purchase Order. The Manufacturer shall be solely responsible for the adequacy of the ”Preparation for Shipment” provisions employed in respect of materials and application, to provide materials to their destination in ex-works condition when handled by commercial carrier systems.
• Each “shipping section” shall be provided with a permanently-attached readily visible, identification tag. Installation hardware shall be uniquely identified and packaged for easy identification. Hardware identification shall be the same as that shown on the Manufacturer’s installation drawings/instructions.
• (*) Packaging for storage/shipping shall be suitable for Owner’s storage prior to installation as indicated on the Data Sheet.

10.0 TABLES

TABLE 1

NON-SEGREGATED PHASE BUS DUCT BIL

TABLE 2 DOCUMENTATION REQUIREMENTS

FOR ELECTRICAL BUS DUCT 480 VOLT AND HIGHER PER EP 13–24–1

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