Power-Style QED-2 Switchboards – Instruction Bulletin PDF
80043-055-16

Installation

Correct installation of Power-Style QED-2 switchboards is essential for proper operation of all switchboard components. Study the associated instruction books and all drawings carefully. In most cases, all drawings are sent to the purchaser before a switchboard is shipped to enable adequate planning.

DANGER
roof collapse
Do not stand, lie, place heavy objects, or place a large load on the roof. The top of the switchboard is not designed to support the weight of an installer.
Failure to follow these instructions will result in death or serious injury.

Location

Find the designated area on the building floor plan for the switchboard installation. The location chosen for installation must provide working clearances complying with Section 110.26 of the National Electrical Code® (NEC®) or Section 2308 of the Canadian Electrical Code (CEC) Part 1.

  • Front-accessible switchboards require field connections, including mains, branches, ground bus, and neutral bus, that are accessible and maintainable from the front.

  • For switchboards having rear ventilation, allow a minimum 1/2-in. (13 mm) clearance between the rear of the switchboard and the wall for proper ventilation. Equipment drawings identify switchboards requiring rear or side access.

  • Switchboards that require rear access for installation, field connections, or maintenance (such as filter replacement), require 30 in. (762 mm) of working space per NEC 110.26.

  • If the switchboard is in a wet location or outside of the building, enclose it in an outdoor enclosure or equipment to prevent moisture or water from entering and accumulating within the enclosure. Outdoor-rated switchboards drain to the rear, so there must be at least a 1/2-in. (13 mm) clearance between the rear of the switchboard and a wall or other obstruction for proper drainage.

  • Choose a location for installation that is well ventilated. The temperature of the area should not exceed 40°C (104°F).

Foundation Preparation

The floor or foundation must be strong enough to support the weight of the switchboard without sagging. The surrounding floor area must gently slope away from equipment and toward a drain.

NOTE: For seismic qualifications, read Anchoring for Seismic Qualifications before pouring the floor or foundation.

Power-Style QED-2 switchboards are assembled on true and level floors at the assembly plant. To ensure correct bus bar alignment, the mounting pad or final installation site must be smooth and level. If parallel steel floor channels are imbedded for mounting the switchboard, the floor channels must be level over their entire length to avoid distortion of the switchboard structure. Each channel must be level with the finished floor.

When pouring the foundation, make provisions for conduits entering the switchboard from below and carrying the incoming and/or outgoing cables, control wiring, and ground cable. The bottom view in the equipment drawing shows the available conduit area for correct layout.

Conduits must project above the finished floor by two (2) in. (51 mm). However, to simplify moving the shipping sections into place, install the conduits flush with the concrete and, after the sections are in their final position, add the appropriate extension sleeves. Otherwise, raising the shipping section on timbers or lifting it by a crane to clear the conduit hubs becomes necessary. Before pouring the foundation, consider installing additional conduits for future circuits.

Switchboard Preparation

  1. Remove dirt and debris from the foundation and surrounding area before moving the switchboard into final position.

  2. Move the switchboard to its final installation site and take each shipping section off its shipping stringers. For switchboards greater than 24 in. (610 mm) deep, remove the center base channel.

  3. Remove all packing materials. If the switchboard is equipped with a bottom closure plate in each vertical section, remove and retain the plates for reuse. When bottom closure plates are furnished, the customer must create any holes necessary for conduit entering the bottom of the switchboard. After creating the holes, reinstall the closure plate.

For ArcBlok Main section, refer to Switchboard Preparation - Bottom Fed ArcBlok Main Section.

General Installation

NOTICE
improper stress on bus
Level and align adjacent shipping sections with one another. Ensure proper alignment of horizontal main through bus and proper splice bus connections.
Failure to follow these instructions can result in equipment damage.

Install the switchboard into its final position by leveling progressively each section and bolting the frames together, if separated. Position shipping sections as follows:

  1. Maneuver each shipping section into the desired position using the procedures under Handling.

  2. Carefully lower the section over the conduit stubs to comply with the “available conduit area” as shown in the bottom view of the equipment drawings. Otherwise, there might not be sufficient cable bending space.

  3. Level the shipping section.

  4. After installation of each section is complete, make the through bus splice connection to the preceding section before installing the next section.

Joining Shipping Sections-Outdoor Switchboards

  1. Remove the center top cap (see Joining Adjacent Sections—Outdoor Switchboards) from the left-hand section, and retain all hardware for reuse.

    Joining Adjacent Sections—Outdoor Switchboards

  2. When possible, open or remove the front and rear doors and panels, providing access to bolt adjacent shipping sections together.

  3. Remove three 0.5 in. (13 mm) diameter knockouts from the front vertical corner channel and three from the rear vertical corner channel (a total of six per frame side) as indicated by the arrows in Joining Adjacent Sections—Outdoor Switchboards.

  4. Position each adjacent section, carefully leveling it and aligning it with the previous section. If lifting straps are provided, completely remove them from the sides being bolted together so the sections are joined flush. The only gasket required between sections is provided on the roof flange.
    NOTE: If lifting strap removal is not required to join sections, leave the lifting strap on the switchboard. Verify that the bolt is tight to maintain NEMA Type 3R integrity.

  5. Place the six bolts (3/8-16 x 1 in.) provided through the holes created in step 3 to join adjacent sections.

  6. Make the through bus splice connections to the preceding section.

  7. Replace the center top cap removed in step 1.
  8. Replace and secure the front and rear doors and panels removed in step 2.

Joining Shipping Sections-Indoor Switchboards

  1. Position each adjacent section, carefully leveling and aligning it with the previous section. If lifting straps are provided, completely remove them from the sides being bolted together so the sections can be joined flush.

    NOTE: Leave the other lifting straps on the switchboard if their removal is not required to join adjacent sections flush.

    Indoor Switchboards

  2. Open or remove the front and rear doors and panels, providing access to bolt adjacent shipping sections together.

  3. Place the six bolts (3/8-16 x 1 in.) provided through the existing holes in the front and rear vertical corner channels to join adjacent sections (see Indoor Switchboards).
  4. Make the through bus splice connections to the preceding section.
  5. Replace and secure all front and rear doors and panels removed in step 2.

Anchoring for Seismic Qualifications

QED-2 equipment that is seismically certified has been qualified to the site-specific seismic requirements of the listed model building codes and/or standards. Optional construction features may be required, depending on the location of the installation and the particular code and/or standard of interest. Seismic certificates of compliance are provided with all seismically-certified QED-2 equipment. To maintain the validity of this certification, equipment anchorage to the primary building structure is required.

Responsibility for Mitigation of Seismic Damage

For the purposes of the model building codes, QED-2 equipment is considered non-structural building components. Equipment capacity was determined from triaxial seismic shake table test results as defined in the International Code Counsel Evaluation Service (ICCES) Acceptance Criteria for Seismic Qualification Testing of Nonstructural Components (AC156). Unless otherwise indicated, an equipment importance factor of 1.5 (Ip = 1.5) was used, indicating that equipment functionality was verified before and after shaker table seismic simulation testing. This importance factor is indicative of critical facilities where maximizing the probability of post event functionality is a priority. ASCE/SEI 7 recognizes AC 156 as an appropriate methodology for qualifying equipment to its requirements.

Consider incoming and outgoing cable and conduit as related but independent systems. They must be designed and restrained to withstand the forces generated by the seismic event without increasing the load transferred to the equipment. This system must be able to transfer the loads created by a seismic event to the load-bearing path of the building structural system.

Maintaining Seismic Certification

Seismic qualification of non-structural components by Schneider Electric is just one link in the total chain of responsibility required to maximize the probability that the equipment remains intact and functional after a seismic event. During a seismic event, the equipment must be able to transfer the loads that are created through the mounting pad and anchorage to the load-bearing path of the building structural system. The design Engineer of Record is responsible for detailing the equipment connection and anchorage requirements for the given installation. The installer and manufacturers of the anchorage restraint system are responsible for assuring that the mounting requirements are met. Schneider Electric is not responsible for the specification and performance of these systems.

Anchoring QED–2 Equipment for Seismic Applications

Formed base channels run the width of the section. The channels and connecting braces provide a minimum 0.75 in. (19 mm) diameter hole for fastening the section to the floor. To anchor the QED-2 switchboard to the floor properly, use all four mounting locations for NEMA Type 1 enclosures less than 36 in. (914 mm) deep, all six mounting locations for 36–70 in. (914-1778 mm) deep enclosures, and six of the eight mounting locations for enclosures greater than 70 in. (1778 mm) deep (see Base Channel Floor Anchor Bolt Locations).

Use one 1.25 in. (32 mm) outer diameter Belleville washer (not provided; see Belleville Washer) under the head of each bolt or anchor nut.

Belleville Washer


Additionally, each NEMA Type 1 enclosed section includes four top-located hard points for attaching two upper lateral braces (braces and hardware are not supplied) to the QED-2 structure for top structural restraint (see Top Anchor Hard-Point Locations and Top Anchor Mounting Hardware).

Top structural restraint is required for QED-2 equipment installed:

  • when indicated by the seismic qualification certificate, or

  • when displacement at the top of the equipment cannot be tolerated.

NOTE: Anchoring hardware is not furnished with the QED-2 equipment.

After the QED-2 switchboard and adjacent equipment are properly joined and the entire structure is bolted to the floor, install the incoming service conductors and load side cables. During an earthquake, the top of the QED-2 switchboard can move in any direction. Any top incoming cables must accommodate this motion. Do not use the QED-2 enclosure (particularly the top) to mount exterior equipment.

Base Anchoring

  1. To anchor the switchboard to the floor properly, use all of the designated 0.75 in. (19 mm) diameter mounting hole locations as illustrated in Base Channel Mounting Hardware. The enclosure dimensions corresponding to Base Channel Floor Anchor Bolt Locations are listed in Enclosure X,Y, Z Dimensions in Inches (mm).

    Enclosure X,Y, Z Dimensions in Inches (mm)

    Enclosure Width →

    12 in.
    (305 mm)

    24 in.
    (610 mm)

    30 in.
    (762 mm)

    36 in.
    (914 mm)

    42 in.
    (1067 mm)

    48 in.
    (1219 mm)

    54 in.
    (1372 mm)

    ↓Enclosure Depth

    24 in.
    (610 mm)

    X = 6 (152)
    Y = 21 (533)

    X = 18 (457)
    Y = 21 (533)

    X = 24 (610)
    Y = 21 (533)

    X = 30 (762)
    Y = 21 (533)

    X = 36 (914)
    Y = 21 (533)

    X = 42 (1067)
    Y = 21 (533)

    X = 48 (1219)
    Y = 21 (533)

    36 in.
    (914 mm)

    X = 6 (152)
    Z = 16.5 (419)
    Y = 33 (838)

    X = 18 (457)
    Z = 16.5 (419)
    Y = 33 (838)

    X = 24 (610)
    Z = 16.5 (419)
    Y = 33 (838)

    X = 30 (762)
    Z = 16.5 (419)
    Y = 33 (838)

    X = 36 (914)
    Z = 16.5 (419)
    Y = 33 (838)

    X = 42 (1067)
    Z = 16.5 (419)
    Y = 33 (838)

    X = 48 (1219)
    Z = 16.5 (419)
    Y = 33 (838)

    48 in.
    (1219 mm)

    X = 6 (152)
    Z = 22.5 (572)
    Y = 45 (1143)

    X = 18 (457)
    Z = 22.5 (572)
    Y = 45 (1143)

    X = 24 (610)
    Z = 22.5 (572)
    Y = 45 (1143)

    X = 30 (762)
    Z = 22.5 (572)
    Y = 45 (1143)

    X = 36 (914)
    Z = 22.5 (572)
    Y = 45 (1143)

    X = 42 (1067)
    Z = 22.5 (572)
    Y = 45 (1143)

    X = 48 (1219)
    Z = 22.5 (572)
    Y = 45 (1143)

    54 in.
    (1372 mm)

    X = 6 (152)
    Z = 25.5 (648)
    Y = 51 (1295)

    X = 18 (457)
    Z = 25.5 (648)
    Y = 51 (1295)

    X = 24 (610)
    Z = 25.5 (648)
    Y = 51 (1295)

    X = 30 (762)
    Z = 25.5 (648)
    Y = 51 (1295)

    X = 36 (914)
    Z = 25.5 (648)
    Y = 51 (1295)

    X = 42 (1067)
    Z = 25.5 (648)
    Y = 51 (1295)

    X = 48 (1219)
    Z = 25.5 (648)
    Y = 51 (1295)

    60 in.
    (1524 mm)

    X = 6 (152)
    Z = 28.5 (724)
    Y = 57 (1448)

    X = 18 (457)
    Z = 28.5 (724)
    Y = 57 (1448)

    X = 24 (610)
    Z = 28.5 (724)
    Y = 57 (1448)

    X = 30 (762)
    Z = 28.5 (724)
    Y = 57 (1448)

    X = 36 (914)
    Z = 28.5 (724)
    Y = 57 (1448)

    X = 42 (1067)
    Z = 28.5 (724)
    Y = 57 (1448)

    X = 48 (1219)
    Z = 28.5 (724)
    Y = 57 (1448)

    72 in.
    (1829 mm)

    X = 6 (152)
    Z1 = 28.5
    Z2 = 40.5 (1029)
    Y = 69 (1753)

    X = 18 (457)
    Z1 = 28.5 (724)
    Z2 = 40.5 (1029)
    Y = 69 (1753)

    X = 24 (610)
    Z1 = 28.5 (724)
    Z2 = 40.5 (1029)
    Y = 69 (1753)

    X = 30 (762)
    Z1 = 28.5 (724)
    Z2 = 40.5 (1029)
    Y = 69 (1753)

    X = 36 (914)
    Z1 = 28.5 (724)
    Z2 = 40.5 (1029)
    Y = 69 (1753)

    X = 42 (1067)
    Z1 = 28.5 (724)
    Z2 = 40.5 (1029)
    Y = 69 (1753)

    X = 48 (1219)
    Z1 = 28.5 (724)
    Z2 = 40.5 (1029)
    Y = 69 (1753)

    Base Channel Floor Anchor Bolt Locations

    NOTE: See Enclosure X,Y, Z Dimensions in Inches (mm) for X, Y, Z dimensional values.

  2. Depending on the frame size (see Base Channel Floor Anchor Bolt Locations), use either four or six anchorage points in the locations shown in Base Channel Mounting Hardware.

    Base Channel Mounting Hardware

    NOTE: Base channel mounting hardware detail shown for reference purposes only. Anchoring hardware is not furnished with the switchboard. Covers and internal hardware shown removed for illustration purposes.

  3. Once the switchboard is in place, secure the base channels. The hardware used at each anchorage point must include a 1.25 in. (32 mm) diameter Belleville washer, as illustrated in Base Channel Mounting Hardware.

    NOTE: The “TOP” side of the Belleville washer must be facing up.

Top Anchoring/Restraint

For installation at locations indicated by the seismic qualification certificate, or where displacement cannot be tolerated at the top of the switchboard during a seismic event, use top restraints attached to the equipment hard points.

NOTE: Anchoring hardware is not furnished with the switchboard.

  1. The four 0.88 in. (22 mm) diameter mechanical knock-outs shown in Top Anchor Hard-Point Locations serve as hard points for application of a top restraint system.

    NOTE: By code, it is the responsibility of the design Engineer of Record to determine the top restraint methodology for the intended building application.

    Top Anchor Hard-Point Locations

  2. Detach the top plate from the main switchboard enclosure; retain the screws.

  3. Remove the four 0.88 in. (22 mm) diameter mechanical knock-outs as directed by the design Engineer of Record.
  4. With the knock-outs removed, reattach and re-secure the top plate to the enclosure using the screws removed in step 2.
  5. Attach the top restraint system using a 1/2-13, Grade 5 bolt, a 1 in. (25 mm) diameter steel washer, a 1.25 in. (32 mm) diameter Belleville washer, and a hardened 1/2-13 nut as shown in Top Anchor Mounting Hardware.

    Top Anchor Mounting Hardware

  6. After all switchboard sections are properly joined and the entire structure is properly anchored, install the incoming service conductors and load side cables.

    NOTE: Do not use the switchboard enclosure (particularly the top) to mount exterior equipment, except for conduit.

Anchoring the Switchboard

Although sections are freestanding, a hard bump or shifting movement can result in damage to the splice joints between sections and conduit hubs connected to the sections. Therefore, each individual section must be anchored to the floor.

Formed base channels run the width of the shipping section. The channels have 0.75 in. (19 mm) diameter clearance holes for fastening the section to the floor (see Switchboard Base Channels).

  1. Anchor each section to the floor with hardware suitable for installation of electrical equipment (not furnished).

    Switchboard Base Channels

  2. Install the incoming service conductors and load side cables.

NOTE: If the switchboard consists of only one shipping section, proceed to Grounding and Bonding.

Through Bus Splice Connections

DANGER
hazard of electric shock, explosion, or arc flash
Do not install through bus splice connectors with the switchboard energized.
Failure to follow these instructions will result in death or serious injury.

Through bus splice connectors and/or hardware, along with installation instructions, are provided with each shipping split. Follow the installation instructions, and torque splice bolts to the value given in Torque Values for Electrical Connections.

If through bus bars are wrapped with an insulative material, cover the splice connections with the material provided.

For splice connections with bus on the front and rear of an insulating tube, the U-shaped, copper connector must be centered around the tube. Proper Orientation of U-shaped Splice Connector shows the proper orientation of the connector.

NOTE: The U-shaped connector fits snugly against the insulating tube when installed correctly. It is pulled away from the insulating tube in Proper Orientation of U-shaped Splice Connector to show the orientation of the connector slot.

Proper Orientation of U-shaped Splice Connector

Ground Bus Splice Connections

NOTE: Proper installation is essential for equipment ground fault systems.

Ground Bus Splice Connection

Series 2 Ground Bus Splice Connection

Grounding and Bonding

A system is “grounded” if it is grounded at any point ahead of the switchboard, whether the grounded conductor (neutral) is carried through to the loads, or not.

Service Equipment-Grounded System

For solidly-grounded systems used as either service equipment or as a main switchboard on a separately derived system:

  1. Run a grounding electrode conductor from the grounding electrode at the installation site to the grounding electrode conductor connector (ground lug) located on the switchboard ground bus (or on the neutral bus, if so indicated on the equipment drawing) (see Grounding Electrode Connector). Select the material and size of this grounding electrode conductor to comply with Sections 250.62 and 250.66 of the NEC or Sections 10-204 and 10-206 of the 1998 CEC, and install it as specified in Section 250.64 of the NEC or Section 10-908 of the 1998 CEC.

    Grounding Electrode Connector

  2. Install the main bonding jumper between the neutral bus and the ground bus (see Main Bonding Jumper or Series 2 Main Bonding Jumper). For torque values, refer to Torque Values for Electrical Connections.

    NOTE: If the switchboard is fed from multiple sources (for example, double-ended systems), there may be two or more main bonding jumpers to install.

Main Bonding Jumper

Series 2 Main Bonding Jumper

In Canada, a main bonding jumper bus or cable is provided between the neutral bus and ground bus. When the bonding jumper must be disconnected (for example, for a Megger® test):

  1. Remove the main bonding jumper bus or cable lug with cable from the neutral bus. This is normally located near the line neutral lugs.

  2. Secure the main bonding jumper bus or cable and lug to maintain the required distance from phases and neutral.

NOTE: If the switchboard is fed from multiple sources (for example, a double-ended system like a main-tie-main), there may be two or more main bonding jumpers installed.

For grounding and bonding in ArcBlok Main section, see Grounding and Bonding-Bottom Fed ArcBlok Main Section.

Service Equipment-Ungrounded System

For ungrounded systems used as either service equipment, or as a main switchboard on a separately derived system:

  1. Run a grounding electrode conductor from the grounding electrode at the installation site to the grounding electrode conductor connector (ground lug) located on the switchboard ground bus.

  2. Select the material and size of this grounding electrode conductor to comply with Sections 250.62 and 250.66 of the NEC or Sections 10-700 and 10-702 of the 1998 CEC, and install it as specified in Section 250.64 of the NEC or Section 10-204 of the 1998 CEC.

Non-Service Equipment

For either grounded or ungrounded systems, when a switchboard is not used as service equipment nor as a main switchboard on a separately derived system:

Use equipment grounding conductors sized according to Section 250.122 of the NEC or Section 10-206 of the 1998 CEC to connect the switchboard frame and ground bus to the service ground.

High-impedance Grounded Neutral Systems

For high-impedance grounded neutral systems:

Ground the system following the instructions provided with the system grounding equipment and in compliance with Section 250.36 of the NEC. Confirm that the switchboard frame and ground bus are bonded in accordance with Section 250.102 of the NEC.

Busway Connections

Schneider Electric switchboards are manufactured with two different styles of busway connections:

  • Qwik Flange™ is used on indoor switchboards only.

  • “Dummy” flanged end. This type is used on some indoor switchboards, but primarily on outdoor units. The dummy flanged end must be removed to allow actual busway flanged end installation. Either the dummy or actual busway flanged end must be in place before energizing the switchboard.

.

NOTE: Do not use the switchboard to support the weight of the busway connection. Support the busway independently. When the busway is installed, make sure no areas of the roof are bowed downward. This minimizes the chance of water pooling.

Busway Connection-NEMA Type 1 (Indoor) Only (Qwik Flange)

DANGER
HAZARD OF ELECTRIC SHOCK, EXPLOSION, OR ARC FLASH
Turn off all power supplying the switchboard and busway before installing connections.
Failure to follow these instructions will result in death or serious injury.

Follow the instructions in this section to make Qwik Flange busway connections (see Qwik Flange Installation and Qwik Flange):

  1. Remove any protective covering from the opening in the switchboard.

  2. Slip the busway joint into the switchboard connectors.

  3. Check the joint bolt alignment; the center line (C/L) of the joint bolt to the switchboard surface must be 0.95 in. (24 mm) (see Qwik Flange Installation).

    Qwik Flange Installation

    Qwik Flange

  4. Attach the side closing plates using two 5/16 in. bolts (provided). When installed properly, the holes in the side closing plates align with the holes in both the switchboard and busway.

  5. Use an 18 in. (457 mm) or longer wrench to torque the joint bolt until the outer break-away head twists off. Do not allow the break-away bolt head or red warning disc to drop into the switchboard.

  6. Slip the remaining two small closing plates into position by aligning with the holes in the switchboard. Use the four 1/4-20 screws provided to secure the equipment.
  7. Confirm proper phasing of the installed busway before energizing.

Busway Connections–NEMA Type 1 (Non-Qwik Flange) and NEMA Type 3R

If this style of connection for busway is furnished, the busway “dummy” flanged end must be removed before installing the busway (see Cable Restraint Example).

DANGER
HAZARD OF ELECTRIC SHOCK, EXPLOSION, OR ARC FLASH
Turn off all power supplying the switchboard and busway before installing connections.
Failure to follow these instructions will result in death or serious injury.

  1. From inside the switchboard, remove the 1/2 in. (13 mm). bolts that fasten the switchboard bus to the busway dummy nonmetallic flanges. Retain all hardware for reuse.

  2. Remove all screws securing the busway dummy flanged end to the switchboard enclosure.

  3. Remove the busway dummy flanged end (see Removing the Busway Dummy Flanged End).

    Removing the Busway Dummy Flanged End

    		  

  4. Install the actual busway flanged end to the switchboard bus connectors provided in the switchboard (see Flanged-End Connections). Insert the flanges between the switchboard bus connectors so that the mounting holes in the collar of the flanged end align with the pre-drilled holes in the switchboard enclosure.

    Flanged-End Connections

  5. Line up the holes in the bus bar flanges, and reinstall the 1/2 in. (13 mm) hardware that was removed in step 1 as shown in Reinstalling the 1/2 in. (13 mm) Hardware.

    Reinstalling the 1/2 in. (13 mm) Hardware

    NOTE: The convex side (marked “Top”) of one conical washer must be against the bolt head, and the convex side of the second conical washer must be against the hex nut.

  6. Torque the bolts inserted in step 5 as indicated in Torque Values for Electrical Connections.

  7. Assemble the busway collar to the switchboard enclosure with the screws provided.
  8. Ensure that the busway integral ground is connected to the switchboard ground bus.
  9. Confirm busway phasing before energizing.

Conduit Area

  1. Locate and terminate all conduit in the switchboard enclosure in the “available conduit area” designated on the equipment drawing.

    NOTE: On switchboards greater than 24 in. (610 mm) deep, the center base channel can be removed for additional conduit area. Exception: Do not remove any base channels when seismic restraint is required.

  2. Install the conduit properly. Use hubs, locknuts, and bushings to protect the cables and prevent condensation on the conduit from entering the switchboard.

    NOTE: If top entry, do not use the top of the switchboard to support the weight of the conduit. Support the conduit independently. When the conduit is installed, make sure no areas of the roof are bowed downward. This minimizes the chance of water pooling.

    If bottom closure plates are furnished, the customer must remove the plates, create holes in them for any conduit entering the bottom of the switchboard, and then reinstall the plates.

    Under seismic conditions, consider using top restraints if movement of the top of the switchboard is an issue.

  3. Bond all conduit hubs to the switchboard enclosure with approved electrical connections.

Cable Pulling

Power-Style QED-2 switchboards are constructed to customer specifications for the cable entrance arrangement (for example, top or bottom feed). Switchboard components are arranged to give proper cable clearance and bending space for cables entering or exiting the switchboard as specified on the equipment drawing.

  1. Use only cable sizes suitable for a proper fit with the corresponding lugs.

  2. Pull the proper number of line side and load side cables according to the load served and the NEC or CEC.

  3. Position the cables inside the switchboard so that they are not subject to physical damage.

  4. Maintain the largest possible bending radii and proper clearance to bus bars and grounded parts. If any cables are lying or bearing on structural members, support them to relieve this condition or place suitable protective material at the bearing point to protect the cable insulation.

  5. Be certain to run all phase conductors, including the neutral, through the same opening where cables enter or leave the switchboard, or pass through any metal that has magnetic properties. Otherwise, overheating can result. See Section 300.20(A) of NEC.

  6. When instructed, brace or cable-lace the conductors.

Cable Terminations

  1. Use a proper insulation stripping tool to strip a length of insulation from the end of the cable sufficient to fit into the full length of the lug barrel. Be careful not to nick or ring the strands.

  2. Thoroughly clean aluminum cable contact surfaces with a wire brush, or scrub them with an abrasive cloth to remove oxides and foreign matter.

  3. Immediately apply an acceptable joint compound to the bare aluminum surfaces.

  4. If compression-type lugs are furnished on any switch or circuit breaker, or as the main incoming power lugs, unbolt and remove them to create sufficient room for crimping the lugs to the cables with the crimping tool.

    1. Insert the cable into the lug barrel and, using the crimping tool, make the specified number of crimps per the recommendations of the manufacturer.

    2. Wipe excess joint compound from the connector and insulation.

    3. Remount the lugs onto the bus bars, switches, or circuit breakers. Torque the bolts to the values given in Torque Values for Electrical Connections.

    Set screw-type lugs may be furnished as main incoming lugs and are standard on molded case circuit breakers and QMB/QMJ/QMQB* fusible switches.

  5. Torque these lugs to, but do not exceed, the specified values. Torque values for circuit breaker and switch lugs are marked on these units. Torque values for other switchboard lugs are marked on the switchboard (Multiple Conductor Neutral and/or Ground Bar).

Cable Restraint for Short-circuit Current Rating (SCCR)

For ArcBlok Main Section, refer to Appendix A-Instructions for ArcBlok Main Section.

Cable restraint is recommended for lugs mounted on bus when the following conditions are met:

  • Unsupported cable lengths are greater than 3.5 ft. (1 m)*

    AND

  • Cables meet the Yes criteria shown in Cable Restraint Criteria.

Cable Restraint Criteria

Cable Ampacity

Available Short Circuit Trip Current (RMS)

< 65 kA

65 to < 85 kA

85 to < 150 kA

150 to 200 kA

≤ 800 A

No

Yes

Yes

Yes

 1200 A

No

No

Yes

Yes

 1600 A

No

No

Yes

Yes

 2000 A

No

No

Yes

Yes

 2500 A

No

No

No

Yes

 3000 A

No

No

No

Yes

≥ 4000 A

No

No

No

No

OR

  • When otherwise specified.

    NOTE: For I-Line™ circuit breakers, or if the lugs are in the circuit breaker, refer to the instruction bulletin for the specific circuit breaker.

Cable Restraint Example

NOTICE
cable movement under short-circuit conditions
Restrain all cables, including neutral cables, in the switchboard installation when the conditions stated in Cable Restraint Example are met.
Failure to follow these instructions can result in equipment damage.

When cable restraints are required, perform the following steps.

NOTE: Wrap cables using 1/2 in. (13 mm) diameter sisal rope, 3/8 in. (9.5 mm) diameter nylon rope, or equivalent.

  1. Begin wrapping the cables (see Wrapping Cables (neutral cables not shown)) a maximum distance of 11 in. (279 mm) from the end of the lugs. Continue to wrap the cables on 11 in. (279 mm) center (s) up to the point where the cables leave the enclosure.

    1. Wrap the cables four times as shown, leaving three ft. (1 m) of excess rope at the first end (A).

    2. Pull the rope (B) taut.

      Wrapping Cables (neutral cables not shown)

  2. Wrap the rope several times (see Wrapping the Space Between Cables) until the space between the cables is completely filled.

    1. Weave the final rope loop underneath the previous loop (C).

    2. Bring the rope through the right-hand space.

    3. Pull the rope taut.

      Wrapping the Space Between Cables

  3. Wrap the rope several times until the space between the cables (see Finish Wrapping the Space Between Cables) is completely filled.

    1. Weave the final rope loop underneath the previous rope loop (D).

    2. Pull the rope taut.

      Finish Wrapping the Space Between Cables

  4. Tie the rope ends (1) and (2) together (see Tying Rope Ends Together) until they are taut. Cut off excess rope, and tape ends to prevent fraying.

    Tying Rope Ends Together

  5. Recheck torques of wire binding screws after securing the cables.

    NOTE: Refer to the torque label supplied with the switchboard for torque values.
QR Code is a registered trademark of DENSO WAVE INCORPORATED in Japan and other countries.

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