2.0 Padmount Transformer Service

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2.1 General introduction

A padmount transformer service refers to a ground-mounted transformer located on private property.
Typical installations include medium to large commercial applications, large houses, and multi-family sites.
Please see Table 1 below for a summary of your responsibilities as the customer and EDTI's responsibilities.
If you decide that you require a padmount transformer service, please complete the Commercial or Single-Family Residential Application Form and email it to ces@epcor.com.
See the Additional Information in Section 9 to learn about such topics as temporary power, splicing, operations, equipment relocation, and pre-inspection checklists.
The information is divided into sections to make it easier for you to find what you need, but EDTI strongly suggests that you read all the information before starting.
If there are any differences between this information and EDTI's Terms and Conditions, the Terms and Conditions will govern. In addition, regulations contained in the Canadian Electrical Code, Alberta Electrical Utility Code, Alberta Safety Codes Act, and Alberta Occupational Health and Safety Act must be followed.
For the safety of public, City of Edmonton bylaws require residents or property owners to always keep power assets clear of trees, shrubs, rocks, debris and other items.
The customer must comply with the clearances set out in the Canadian Electrical code for required vertical clearances when crossing to other utilities.

Table 1

Customer's Responsibilities

Complete civil work on private property. This typically includes all trenching, ducting, pull boxes, concrete bases for any padmount equipment, grounding, and guardrails.
Supply and install secondary cable.
Install Current Transformers and Potential Transformers.
Supply the primary cable on multi-family sites.

NOTE: The customer owns and maintains all transformer bases, switching cubicle bases, ground grids, primary ducts, and all secondary works on private property. Customer owns and maintains primary cable in MFU sites.

EDTI's Responsibilities

Complete all work on public property.
Supply primary cable, except for multi-family sites, where the customer supplies the primary cable.
Supply, install, and terminate all padmount equipment.
Supply Current Transformers and Potential Transformers
Supply and install revenue metering equipment.

NOTE: EDTI owns and maintains all transformers, switching cubicles, primary cable (except for multi-family sites), and revenue metering equipment.

Service Connection Point (Service Entry Point)

Property line.

Point of Service Termination (Electrical Connection Point)

Property line for multi-family sites, transformer for all other installations.

2.2 Standard Supply Voltages 2.3 Permits and Inspections 2.4 Service Connection Agreement 2.5 Drawing Requirements 2.6 Horizontal Clearance to Other Utilities 2.7 Service Entry Point 2.8 Electrical Room 2.9 Main Switch or Breaker Minimum Interrupting Capacity 2.10 Maximum Horsepower of Motors 2.11 General Service Requirements 2.12 Trenching and Backhoe 2.13 Service Ducts 2.14 Duct Bends 2.15 Ground-Mounted Pull Boxes 2.16 Equipment Access 2.17 Site Housekeeping 2.18 Padmount Transformers and Switching Cubicles 2.19 Ground Grids and Guardrails for Padmounted Equipment 2.20 Blast Walls 2.21 Conductors 2.22 Cable Installation 2.23 Multi-Family Developments and Mobile Home Parks 2.24 Duplex, Triplex, and Fourplex Units 2.25 Service Interruption 2.26 Next Steps

2.2 Standard Supply Voltages

To see the standard voltages available from EDTI for this type of service, please see the Select the Service Type That Works for You (1.4) section.
Maximum service limits apply to services within our 15 kV and 25 kV service areas. For any new or increased services in the 5 kV distribution area, contact us for limits. Refer to Drawing 29 for the primary voltage in your area, and contact us for confirmation.
240 V, 3-phase, 3-wire services are not available from padmount transformers.
1-phase equipment cannot be connected to 240 V, 3-phase, 3-wire services.
Two or more services of the same voltage will not be supplied to the same premises. An example would be a 120/240 V, 1-phase, 3-wire service and a 120/208 V, 3-phase, 4-wire service.

2.3 Permits and Inspections

As a customer, you or your contractors are responsible for:

Obtaining all permits, certificates, licences, inspections, reports, and other authorizations necessary for installing and operating the service connection. EDTI is not required to start or continue operation of a service connection unless the customer has complied with the licensing requirements of EDTI and all other authorities.
Submitting an electronic copy of the electrical wiring permit, civil electrical inspection (if required), and final electrical inspection report to EDTI Customer Engineering Services.
Ensuring that an Electrical Safety Codes Officer inspects all internal wiring before it's concealed. All transformer and switching cubicles, ground grids, underground wiring, and ducts must be inspected before the trench is backfilled. Contact the City of Edmonton to arrange for inspections. A service connection will not be energized unless you have received inspection approval.
Completing utility searches on private property and notifying Alberta One-Call before any work is done.

2.4 Service Connection Agreement

EDTI requires the customer to sign the Customer Acceptance portion of the estimate letter as confirmation of intent to proceed with construction. This is required before EDTI finalizes the design and issues work orders.
EDTI may require the customer to sign a Construction Commitment Agreement, Electric Service Agreement, and/or Interconnection Operating and Maintenance Agreement.
The customer may be required to make a capital contribution toward the cost of materials and equipment installed on City of Edmonton property or the customer's property.

2.5 Drawing Requirements

EDTI Customer Engineering Services reserves the right of final approval for the location of facilities before EDTI will grant construction approval.
New connection construction cannot start until EDTI has approved all drawings.
A customer requesting a padmount transformer service must submit a copy of the following:

Commercial or Single-Family Residential Application Form
Architectural site plan
Engineer-approved electrical site plan authenticated by a duly registered professional member of APEGA or ASET
Mechanical plans showing water, sewer, and gas lines on private property

Drawings must be in electronic format and follow accepted drafting standards as indicated in this guide.
Drawings will become part of EDTI Customer Engineering Services' record system and must be submitted in PDF and AutoCAD or MicroStation format.
The following information must be included on these plans:

All legal property lines
Streets, avenues, and any other public thoroughfare abutting the property
Locations of planned and existing buildings
Size and location of primary and secondary conductors on the line (source) side of the meter
Size and location of pull boxes and pedestals
Direction of door openings for padmount transformers and cubicles
Location and size of the main distribution panel within the building, including voltage, amperage, phase, wire size, temperature rating (i.e., 75 or 90 degree), and type
A detailed drawing of the electrical room layout
Easements and rights-of-way located on the customer's property
Location and description of all other utilities crossing or located within 3.0 m of proposed power facilities and conductors
Drawings at a scale that will maintain the readability of multiple conductors, which can be submitted as multiple sheets if necessary to meet the readability criteria as long as each sheet is self-contained
Electrical permit number and legal address
Title, block, border, scale, and legend

Please note that all equipment and conductor locations on the drawing are to be dimensioned from the building and property lines and given real-world coordinates. Curb lines may also be included.

EDTI Customer Engineering Services will review and accept drawings and the scope of work.

2.6 Horizontal Clearance to Other Utilities

The following horizontal clearances to other utilities from underground service lines and equipment, including padmount transformers, switching cubicles, guardrails, and ground grids, must be maintained:

Commercial Installations

Primary and Secondary Conductors

2.0 metres to all valves, hydrants, catch basins, manholes, vaults, sanitary and storm sewer lines, septic tanks, fields, and Minnesota mounds. The primary cable cannot cross through septic fields and Minnesota mounds.
1.8 m to all water lines and cc valves.
1.0 m to all gas lines.

Residential Installations (Single-Family and Multi-Family Units)

Primary Conductors

2.0 metres to all valves, hydrants, catch basins, manholes, vaults, sanitary and storm sewer lines, septic tanks, fields, and Minnesota mounds. The primary cable cannot cross through septic fields and Minnesota mounds.
1.8 m to all water lines and cc valves.
1.0 m to all gas lines.

Secondary Conductors

2.0 metres to hydrants, catch basins, manholes, septic tanks, fields, and Minnesota Mounds. Secondary cables cannot cross through septic fields or Minnesota Mounds.
2.0 m to sanitary and storm sewer lines.
1.0 m to water lines and cc valves.
1.0 m to gas lines when in separate trenches. On residential properties where a 4-party joint-use trench is used, there must be a minimum of 0.3 m of separation, and a marker tape must be installed 0.5 m above the service cable.

2.7 Service Entry Point

It is critical that you contact EDTI Customer Engineering Services for your site-specific service entry point (the point where EDTI's infrastructure meets your property line) before beginning construction. The service entry point can differ based on a number of factors.

2.8 Electrical Room

If service capacity exceeds 200 A, service equipment must be located in a separate electrical room of adequate size. The electrical room can only contain electrical and/or communication equipment and must not contain mechanical devices, such as gas or water equipment.
A detail drawing of the electrical room layout must be submitted for EDTI approval.
All electrical rooms must have four walls and a ceiling.
See the Metering section (8.0) for more detail.
EDTI has specific servicing details for the Quarters Downtown Development area. If your development is in this area, which extends from 92 to 97 Street and from 101 to 103A Avenue, please contact us for these details.

2.9 Main Switch or Breaker Minimum Interrupting Capacity

The interrupting capacity of main switches and breakers must be sized according to Table 3.
The minimum interrupting capacity applies to all service entrance equipment.
The interrupting capacities indicated are for one service from one matching transformer.
When a larger transformer is installed to feed several services, the interrupting capacity must match the total capacity of all services.
For temporary services supplied from a permanent transformer, interrupting ratings must match the available fault currents at the transformer.
Due to higher fault levels, services supplied from the network system require larger interrupting capacities. Please see the Network Service Section (6.0) for more information.

2.10 Maximum Horsepower of Motors

The maximum horsepower of motors permitted is identified in Table 2.
Special permission is required before EDTI will grant construction approval for motors larger than those specified in Table 2. Please contact EDTI Customer Engineering Services for more information

2.11 General Service Requirements

The customer is responsible for the installation and maintenance of all civil work on private property, including maintaining the level of equipment. Civil work typically includes trenching, ducting, transformer or cubicle pads, ground grids, guardrails, and pull boxes. See above.
The customer is responsible for installing meter bases on private property.
The location of the meter socket in relation to the main disconnect depends on the voltage. See the Metering Section (8.0).
EDTI owns and installs all equipment on public property.
EDTI retains ownership of transformers, switching cubicles, and primary cables on the line side of the point of service.
Only EDTI employees or their authorized agents can operate or maintain electrical facilities owned by EDTI.
The customer will comply with the standards set out by the Institute of Electrical and Electronics Engineers (IEEE) 519-1992 (Tables 10.3, 10.4, 10.5) when loads producing harmonic distortion are involved. The customer will also comply with the short- and long-term flicker limits as specified in Tables 2 and 6 of CAN/CSA-C61000-3-7 Electromagnetic Compatibility (EMC) – Part 3 – 7.
125 A underground services for residential purposes are not available.
In Alberta, residential services are not designed for electric heating as the primary heat source. If it is to be used as the primary heat source, contact EDTI Customer Engineering Services prior to construction. The customer may be assessed additional costs based on the type of upgrades required.
Typical residential underground services are available at 100 A. To make arrangements for service connections greater than 100 A, contact us.
Voltage drop calculations are the customer's responsibility and must be submitted upon request.
The customer must ensure loading is balanced across all three phases of the service.
Customers are not allowed to take single phase, 120 V service off the three phase, 240 V service.
EDTI will not connect any permanent or temporary services to the City of Edmonton's streetlight system.
The customer must provide space and easements for utility equipment to maintain the flexibility of the power system, if required by EDTI Customer Engineering Services. See the Easement Agreement Section (9.5) for more information.
Connections and disconnections must be done by EDTI or its authorized agents.
EDTI Customer Engineering Services will not permit the installation of service lines crossing public property between private properties.
EDTI must be notified before EDTI will grant construction approval when neutral grounding devices are incorporated into service equipment.

2.12 Trenching and Backhoe

All proposed cable routing and duct work is subject to written approval by EDTI Customer Engineering Services before EDTI will grant construction approval.
As a customer, you cannot do any excavation work on City of Edmonton property, but must complete all trenching on your property.
Underground service lines must be kept a minimum of 1.0 m from the edge of the property line.
The customer's contractor must not trench within 1.0 m of any EDTI wood pole, anchor, transformer, switching cubicle ground grid (2.0 m from the edge of the concrete base and from 300 mm of the guard rail), power pedestal, or energized cable without prior consultation with EDTI. The facilities must be located first using hydro excavating or hand digging before determining where the mechanical excavation limits end.
Ensure that the top of duct is a minimum of 1,000 mm to a maximum of 1,300 mm below finished grade and that the service cable is set on undisturbed soil that is free from rocks, debris, and sudden grade changes. If large lumps of clay and soil have hardened due to drying or freezing, and when a backhoe has been used for electrical service installation, a 150 mm layer of sand must be placed below the cable. For all service installations, a 300 mm layer of sand must be placed above the cable.
A marker tape must be installed 0.5 m above all underground electrical conductors.
The customer must backfill all trenches with material that is free of stones and items with sharp edges.
Backfill must be placed in uniform lifts not exceeding 300 mm and compacted to the City of Edmonton Design and Construction Standards, Volume 2 – Roadways.
Backfill material over cable can be the material trenched with a mechanical trencher, if the inspector deems it suitable. Soil with high thermal resistivity that contains large amounts of organics, peat, black loam, sod, hardened clay, stones, straw, snow, or frozen material will not be acceptable. All backfill material is subject to the inspector's approval. Sand or clean backfill material must be substituted for unsuitable backfill.
The trench must take the most direct route to the meter base location.
Some work may be required over energized primary or secondary cables. This may involve crossing or over trenching the cables. Mechanical excavation is allowed up to 1.0 m from the energized facilities. The facilities must first be located using hydro excavation or hand digging before determining where the mechanical excavation limits end.
EDTI Customer Engineering Services will allow a contractor to over trench up to 5.0 m of energized facilities by hand or hydro excavation. Follow Alberta One-Call procedures and contact us before starting work.
Exposed energized cables cannot be left unattended. If the excavation is narrow or small, the primary cable must be covered with soil bags or some other suitable temporary method. Contact us for more details.
Under no circumstances must energized primary cables be moved or handled in any way.
When a trench has been backhoed, cables must be shaded with 300 mm of sand. Backhoed material cannot be placed over cable.

2.13 Service Ducts

EDTI Customer Engineering Services reserves the right of final approval for the location of facilities before EDTI will grant construction approval.
All permanent commercial services must be in duct.
For residential installations, EDTI highly recommends installing any cable that will ultimately end up under driveways, decks, etc. in duct. See Drawing 2 for a typical underground service installation.
Duct must be installed where primary cable is deemed inaccessible by EDTI. All ducts must be equipped with bell collars to avoid damaging the cable.
The installation of primary service cable under buildings is not permitted.
The customer will provide all conduits (rigid PVC, DB2, Carlon Borguard, Terracon, or other EDTI-approved ducts only), pull boxes, and manholes required for installing the electrical services on the customer's property.
The customer cannot install ducts into an energized manhole or handhole.
Conduit size requirements for primary (high-voltage) cables depend on cable size and voltage. See Drawing 29 for primary voltage and Table 4 for primary cable, duct, and pull box standards.
Contact EDTI Customer Engineering Services to confirm the primary voltage in your area.
Service conduits installed by contractors working on behalf of other utilities or the City of Edmonton must follow EDTI Customer Engineering Services' construction standards. Contractors must not work within 1.0 m of any electrical equipment.
When EDTI conduits have been stubbed to the property line, customers must first confirm that the conduit exposed is the correct one, and then connect their supply conduit to EDTI's conduit. Contact us to arrange for conduit verification.
If the pulling lengths exceed the maximum pulling tension of the cable, a pull box must be installed. See the Ground-Mounted Pull Boxes Section (2.15) for more information.

2.14 Duct Bends

All bends exiting transformers and cubicles must be made of rigid, thick-walled PVC (schedule 40) with minimum wall thickness of 6.0 mm for 4 in., 6.6 mm for 5 in., and 7.1 mm for 6 in. DB2 bends are not acceptable.
An additional 10 ft. horizontal section of rigid, thick-walled PVC must be attached to the bend.
The primary duct must be aligned directly underneath the primary transformer bushings and centred within the base opening, as per Drawings 8 and 9. The conduit bends must exit the earth at 90 degrees.
The customer must ensure all secondary ducts are aligned directly under the secondary bushings of the transformer and centred within the base opening.
All bends must be equipped with bell collars to avoid damaging the cable.
All spare bends are to be covered (taped or covered by some other suitable method) to prevent material falling into them.
Primary ducts exiting switching cubicles must be identified (i.e. identify the piece of equipment the pipe services).
See Drawing 29 for primary voltage and Table 4 for primary cable, duct, and pull box standards.
Precast concrete pad must be removed before inserting additional ducts into existing pads.

2.15 Ground-Mounted Pull Boxes

EDTI Customer Engineering Services reserves the right of final approval of the pull box size and location prior to construction.
If the pulling lengths exceed the maximum pulling tension of the cable, a pull box must be installed. See Drawing 1.
The accumulative total of all bends between pulling points cannot exceed four 90 degree bends, as per Canadian Electrical Code Rule 12-940.
Contact us to perform a cable pulling calculation for your specific site.
The size of the ground-mounted pull box required depends on the type of cable being installed.
See Drawing 29 for primary voltage and Table 4 for primary cable, duct, and pull box standards.
Conduits must enter and leave the pull box at the same level.
Communication cables cannot share the same pull box with primary cables.
Customer-owned facilities cannot share the same pull box with EDTI facilities.
EDTI requires truck access to on-property transformers, switching cubicles, poles, and pull boxes where EDTI will own the cable. See the Equipment Access Section (2.16) for more information.
Rigid, thick-walled PVC (schedule 40) with minimum wall thickness of 6.0 mm for 4 in., 6.6 mm for 5 in., and 7.1 mm for 6 in. must be installed for the first 10 ft. when entering or exiting any pull boxes, manholes, or vaults. DB2 bends are not acceptable.

2.16 Equipment Access

EDTI Customer Engineering Services reserves the right of final approval for the location of facilities before EDTI will grant construction.
EDTI requires truck access to on-property transformers, switching cubicles, poles, and pull boxes where EDTI will be installing the cable.
Access to equipment must be provided on private property. Without special permission from EDTI Customer Engineering Services, public roadways or laneways are not acceptable for access to equipment on private property.
Equipment must be placed beside a 4.6 m wide access roadway, centred in an unimpeded 6.5 m area. The area must be capable of supporting an 18,000 kg truck, plus a transformer weighing up to 6,900 kg (transformers must be unloaded from the side of the vehicle). Outriggers on the truck must extend to a width of 7.0 m.
Any overhang or other obstruction over the access roadway, such as a sign, must have a minimum of 5.0 m of vertical clearance.
If access is through a locked enclosure, the customer shall provide double lock capability on the gate to accommodate an EDTI lock.
Padmounted equipment must be placed in a location not to exceed maximum setbacks from driving surfaces as outlined in Table 5.
Equipment must be placed in a location where it will not create a line-of-sight concern for traffic or pedestrians.
Where the transformer is to be installed in an alcove, the size of the alcove required depends on the size of the transformer and the setback distance of the transformer. Please talk to EDTI Customer Engineering Services for exact requirements and refer to Drawing 3.

2.17 Site Housekeeping

Areas that our crews must access and work in must be clear of construction materials, equipment, debris, trash, and other materials that may pose a safety risk to personnel or damage equipment.
The site must be level and consist of hard-packed material or asphalt.
If a site has substandard housekeeping or is deemed unsafe by EDTI personnel, our personnel will leave the site until the issues are rectified.

2.18 Padmount Transformers and Switching Cubicles

EDTI Customer Engineering Services reserves the right of final approval for the location of facilities prior to construction.
EDTI requires truck access to on-property transformers, switching cubicles, poles, and pull boxes where EDTI will be installing the cable. See the Equipment Access Section (2.16) for more information.
Padmounted equipment must be placed in a location that does not exceed maximum setbacks from driving surfaces, as outlined in Table 5.
Switching cubicles must be connected to EDTI's main line in such a manner as to provide a loop feed. No radial-fed cubicle installations will be allowed on private property.
EDTI will supply, install, and maintain required transformers and switching cubicles, and perform all required primary and secondary conductor terminations at the transformer and switching cubicle.
Required clearances between transformers and buildings can be as high as 6.0 m, depending on the type of transformer used. This is especially true in our 5 kV service area, where 347/600 V transformers are required. See Drawing 29 for the primary voltage in your area, and contact us to confirm the required clearance for your specific installation.
When a transformer or switching cubicle is required on the customer's property, the customer must provide the precast concrete bases with an appropriate ground grid and guardrails. Please see the Ground Grids and Guardrails for Padmounted Equipment Section (2.19).
When the customer is required to install a cubicle base, EDTI will provide a detailed drawing showing how the base must be constructed. EDTI will also confirm the type of cubicle base to be installed. Please see Drawings 4, 5, 6, and 7.
The fault indicator lights adjacent to the "B" compartment of switching cubicles must face the main road. Exceptions to this rule must be approved by EDTI Customer Engineering Services before EDTI will grant construction approval.
Excavation for bases should be stepped so that the native backfill is not disturbed under the ground grid area. This will help prevent rods bending and deformation of the ground grid during backfilling and compaction. The area where the ground grid and rods are installed should not be dug as deep as the base excavation.
The bottom of the excavation where the base will be installed requires 300 mm of compacted ¾ in. road crush (20 mm crushed gravel).
Proper tamping is crucial to ensure transformer and cubicle bases are installed correctly. Ensure that ¾ in. road crush is tamped in 1 ft. lifts. See Drawings 4, 5, and 9.
2 × 10-in. pressure-treated lumber is required under all switching cubicle bases and 1-phase transformer bases. See Drawings 4, 5, 6, 7, and 8.
If the location of the precast base is within 4 m of a building foundation or if soil conditions do not support precast bases, engineered screw piles or concrete piles must be installed. Engineered drawings stamped by a civil/geotechnical engineer must be supplied to EDTI Customer Engineering Services before EDTI will grant approval.
Customer shall submit compaction test reports for all pad installations on site. If adequate compaction cannot be achieved piles are required.
All compaction testing shall meet a minimum of 98% of Standard Proctor Density (SPD)
Within 3.0 m of padmounted equipment, landscaping must slope away from the base at a grade between 3% and 10% to allow for proper drainage and safe operational switching.
3.0 m of working space without obstructions that would interfere with high-voltage switching—such as large rocks, decorative boulders, trees, and fences—must be allowed for on the door sides of transformers and switching cubicles. Examples of appropriate landscaping are sod, wood chips (4" or smaller), or decorative crushed rock. Any decorative crushed rock shall be 20mm (3/4") or smaller, with a minimum of three fractured faces. Smooth, rounded rocks are not permitted. Please note that switching cubicles have two sets of doors.
Concrete and ashphalt are not permitted within the guardrail area to allow for access to grounding for maintenance and repair.
The minimum distance from a temporary panel or temporary shack to the ground grid of a transformer is 3.0 m.
Curbs within 3.0 m of the door sides of transformers and switching cubicles require approval from EDTI Customer Engineering Services prior to construction.
Equipment must not be subject to flooding under runoff conditions.
The height of the top of the concrete base must be between 250 mm and 300 mm above finished grade.
Rough grade must be established at 100 to 150 mm below final grade and marked on the base.
When a switching cubicle base is installed, the customer must install a pull string between the cubicle and transformer.
Customers are responsible for maintaining (including levelling) all transformer and switching cubicle bases installed on their property.
When padmounted equipment is to be located on top of a parkade, detailed drawings under the seal of a registered professional engineer practising structural engineering must be submitted for EDTI approval. EDTI highly recommends taking all necessary steps to avoid this form of construction.
EDTI has specific servicing details for the Quarters Downtown Development area. If your development is in this area, which extends from 92 to 97 Street and from 101 to 103A Avenue, please contact us for these details.

2.19 Ground Grids and Guardrails for Padmounted Equipment

Transformers and switching cubicles must be protected from mechanical damage in accordance with the Canadian Electrical Code, Part I, Rule 26-240(4). Customers are required to provide guardrails for all installations of transformers and switching cubicles on private property.
Guardrails must have removable sections in front of the doors of equipment, as per Drawing 11. Please note that switching cubicles have two sets of doors.
Customers are also responsible for installing ground grids around all padmounted equipment. They must consist of four copper-clad ground rods interconnected by #4/0 bare copper grounding conductor and an additional two #4/0 bare copper grounding conductor tails, connected to the ground bus of the equipment.
A sufficient length of #4/0 bare copper grounding conductor must be installed to allow 3.0 m (no more or less) to be left above the top of the precast transformer base. The conductor must be left in an organized manner to allow for easy removal and shaping.
Ground rod resistance must measure 6 ohms or less.
The minimum distance to the property line for the ground grids of padmount transformers and switching cubicles is 1.0 m.
When non-EDTI equipment is placed within 3.0 m of the edge of EDTI equipment, the ground grid of the EDTI equipment must be bonded using two tails to the ground of the non-EDTI equipment. The customer must show details on the power plan of how the bonding is to be achieved. The detail must also show the clearance between the edge of the EDTI equipment and non-EDTI equipment. The non-EDTI equipment cannot be installed within 1.0 m of the EDTI ground grid. It also can't be located within the guardrails.
Ground grids for padmount equipment located on the top of a parkade must be bonded to the rebar of the building with two #4/0 conductors terminating to a remote ground grid. These conductors must be physically separated. The equipment base must be encircled by a #4/0 bare copper conductor embedded in the concrete 900 mm outside of the base. The gradient control conductor must be bonded to the rebar in the four corners, with two tails from alternate corners entering the base and a length of 3.0 m extending above the top of the base. Detailed drawings under the seal of a registered professional engineer practising electrical engineering need to be submitted to EDTI Customer Engineering Services for approval.
See Drawing 10 for ground grid requirements when cubicles and transformers are next to each other.
Fine-fill clay is required as backfill around the ground grid.

2.20 Blast Walls

Blast walls are only required in rare circumstances. EDTI will inform you if they are required. The blast walls must consist of one of the following:

150 mm thick reinforced concrete
200 mm solid concrete blocks
An alternate equivalent non-combustible rated design (including a possible roof), submitted to EDTI Customer Engineering Services under the seal of a registered professional engineer practising structural engineering

2.21 Conductors

Armoured or metal-sheathed (TECK) cable cannot be used for permanent services.
With our permission, TECK cable can be used for temporary installations. The customer must supply all associated fittings, including connectors, grounding bushings, and weatherheads. See the Temporary Connections Section (9.11) for more details.
See Drawing 29 for primary voltage and Table 4 for primary cable, duct, and pull box standards.
Secondary cables on all residential and multi-family developments must be concentric-neutral direct-buried type (USEB). See Table 6 for details.
For residential installations, ensure the conductor used on private property is compatible with EDTI conductors on City of Edmonton property. Table 6 shows standard cable sizes and types allowed.
For commercial installations, secondary cable must be individual RW90 conductors in duct.
For commercial services connected to a 3-phase padmount transformer, the maximum size of conductor allowed is 500 MCM copper or 750 MCM aluminum.
For commercial services connected to a 3-phase padmount transformer, EDTI recommends colour-coated secondary conductors. (RECOMMENDATION ONLY).
For all residential and multi-family 1-phase services, the maximum conductor size allowed is 4/0 AL XLPE CN.

2.22 Cable Installation

If primary cable pulling lengths exceed the maximum pulling tension of the cable, a pull box must be installed. See Table 4 and the Ground-Mounted Pull Boxes Section (2.15) for further information.
Telephone and television cables can be installed in the same trench as power conductors. Design drawings must be forwarded to the appropriate organizations for their approval.
Cable cannot be installed on building footings or weeping tile.
Secondary cable ends must have heat shrink caps.
Primary cable ends must be wrapped with elastomeric tape (e.g., Greenline) to prevent the migration of moisture in the cable before testing. Elastomeric tape must be wrapped in a spiral shape overlapping half of each previous wrap at a time and then covered with black low-voltage vinyl tape. A minimum of two layers of half-lapped tape is to be applied. Immediately after testing, heat shrink caps must be installed on primary cable ends.
When a switching cubicle base is installed, the customer must install a pull string between the cubicle and transformer.
EDTI will make the final connection in the cubicle, transformer, or pedestal.
EDTI will supply and install all primary conductors in the customer-prepared conduit, but only after the primary ductwork has passed an electrical inspection. Multi-family sites are an exception to this rule.
The customer will supply and install secondary conductors from the customer's switchgear to the transformer location, leaving 5.0 m of conductors above the top of the precast transformer base. After inspection, the conductors must be coiled in a clockwise direction and left in a reasonably clean and organized manner around the inside perimeter of the base to allow for easy removal and shaping.
The phasing of secondary conductors coiled in a transformer must be identified with marking tape at intervals not exceeding 1.0 m or color coded cable installed.
The maximum length of service conductors permitted in a building is 3.0 m, unless they are mechanically protected in rigid metal conduit, in which case the maximum is 7.5 m.
In general, a maximum of six runs of secondary conductors are permitted for all 1-phase padmount transformers. In some circumstances, additional runs may be permitted. Contact us to discuss your specific installation.
In general, a maximum of six runs of secondary conductors, including permanent and temporary services, are permitted for 3-phase padmount transformers up to 1,000 kVA. In some circumstances, additional runs may be permitted. Contact us to discuss your specific installation.
In general, a maximum of eight runs of secondary conductors, including permanent and temporary services, are permitted for 1,500 KVA and 2,500 KVA 3-phase padmount transformers. In some circumstances, additional runs may be permitted. Contact us to discuss your specific installation.
The customer will identify service conductors by the meter address by using long-life ink on a tie-wrap attached to the conductors. This identification is mandatory when there are multiple service connections or when a customer-owned distribution facility, such as a pedestal, is used.

2.23 Multi-Family Developments and Mobile Home Parks

This section applies to multiple-metered residential service connections where 1-phase padmount transformers and service pedestals are required on the customer's property. While other information on padmount transformer installations found elsewhere in this guide also applies, the following information is specific to multi-family developments and mobile home parks.

The customer in multi-family developments must supply the primary cable.
Cable requirements depend on the primary voltage in your area. See Drawing 29 for primary voltage and Table 4 for primary cable, duct, and pull box standards.
Contact EDTI Customer Engineering Services to confirm the primary voltage in your area.
All cables used must strictly conform to EDTI's specifications. The size and type of primary cable accepted by EDTI is either 15 kV or 25 kV 1/C #1/0 AL XLPE CN –J stranded conductor. Solid conductor is not permitted.
All primary cables must be installed in duct on private property.
If the secondary cable is deemed inaccessible by EDTI, secondary cables must be installed in duct.
For multi-family sites where the primary duct is proposed between the last transformer and the cubicle, a coil of primary cable should be direct-buried at the service entry point for EDTI to extend into the switching cubicle. Once EDTI extends the cable into the cubicle, the contractor must install split pipe for conduit coupling.
For sites with more than two transformers, a primary loop feed is required. Please contact us to confirm loop feed requirements.
The customer must supply the manufacturer's cable production test results, as per our specifications for primary cables, prior to cable installation. The test results must be sent to EDTI Customer Engineering Services.
The customer must provide concrete bases for 1-phase transformers, as per Drawing 8.
The customer must install a distribution facility such as a service pedestal. Pedestals must meet Canadian standards and also Canadian Electrical Code requirements for bending radius and space to ensure proper termination. The maximum pedestal rating is 400 A based on the allowable secondary conductors of parallel 4/0 Al from Table 6. Service to an individual dwelling unit cannot be directly connected to the transformer.
The customer must identify service conductors at the padmount transformer by pedestal number, and at the pedestal by meter address, which is the address of the building the meter serves. Meter sockets must be identified by service address and pedestal number. Use a long-life ink on a tie-wrap attached to the conductors for this identification. This is mandatory when a customer-owned distribution facility, such as a pedestal, is used.
For emergency purposes, each pedestal must be identified with the name and phone number of an on-site representative who is available 24 hours a day.
Before energization, the customer must make all terminations on all incoming feeds from the transformer at the service pedestals, and at the neutrals in the pedestals, for the individual services to the units. Customers must not terminate the hot conductors of the service wire in the pedestal. EDTI Customer Engineering Services will extend a customer-supplied conductor to the switching cubicle or pole on City of Edmonton property.
Drawing 12 provides information on submission requirements for multi-family developments.
EDTI will require that a blanket easement be registered on title for most multi-family installations. A blanket easement covers the entire parcel of land.

2.24 Duplex, Triplex, and Fourplex Units

All units on one lot

Each individual unit in a new multiple dwelling will be served as a separate service, unless EDTI Customer Engineering Services agrees otherwise.
If a homeowner's agreement is in place, one service may be installed to a common location on the building to service all the units.
Please contact us to talk about your specific situation.

Each unit on an individual lot

Each individual unit in a new multiple dwelling must be served as a separate service, unless EDTI Customer Engineering Services agrees otherwise.
EDTI may require additional work at the customer's expense to ensure no trespass is created.
Please contact us to talk about your specific situation

Bare-land development

EDTI requires a blanket easement to be registered on the owner's title in EDTI's name. See the Additional Information Section (9.5) for more information on easements.

2.25 Service Interruption

While EDTI makes all reasonable efforts to guard against interruptions, we do not guarantee uninterrupted service.
Without liability of any kind to EDTI, EDTI Customer Engineering Services has the right to disconnect or otherwise curtail, interrupt, or reduce Distribution Tariff Service to customers whenever EDTI reasonably determines, or is told by the Alberta Electric System Operator, that such a disconnection, curtailment, interruption, or reduction is necessary:

To facilitate construction, installation, maintenance, repair, replacement, or inspection of any of EDTI's facilities
To maintain the safety and reliability of EDTI's distribution system
For any other reason, including dangerous or hazardous circumstances such as emergencies, forced outages, potential overloading of EDTI's distribution system, or force majeure

2.26 Next Steps

Your next steps are to ensure the metering is installed correctly and to choose a retailer.

Please see the Metering Section (8.0) to choose the type of metering required for your installation.
You are free to choose any retailer. Regulated power distribution services are not depend on the retailer you choose. For a listing of licensed Alberta retailers, visit www.ucahelps.alberta.ca or call 310-4822 (toll-free in Alberta).

2.0 Padmount Transformer Service

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Updated May 2017

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Service Types

Other Information

2.1 General introduction

Table 1

​Customer's Responsibilities

​EDTI's Responsibilities

Service Connection Point (Service Entry Point)

Point of Service Termination (Electrical Connection Point)

Commercial Installations

Primary and Secondary Conductors

Residential Installations (Single-Family and Multi-Family Units)

Primary Conductors

Secondary Conductors

All permanent commercial services must be in duct.

Armoured or metal-sheathed (TECK) cable cannot be used for permanent services.

The customer in multi-family developments must supply the primary cable.

All units on one lot

Each unit on an individual lot

Bare-land development

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