Instruction Bulletin

Safety Information

This bulletin contains instructions for the installation and operation of QO and Homeline load centers. It also includes installation instructions for standard and tandem branch circuit breakers. See separate instruction bulletins included with advanced function circuit breakers and accessories, when installed.

Preparation

1. Determine the wiring or conduit requirements for the main and branch circuits, as required by local electrical codes.
2. Select the proper cable clamp, or use other approved methods for securing the cable or conduit to the enclosure.
3. Remove the appropriate knockouts required for installation of cable clamps or conduit (Table 1). To remove the knockouts, see Figure 1.

Table 1: Bolt-on Conduit Hubs for Outdoor Load Centers

Figure 1: Removing Knockouts. This figure illustrates the process of removing knockouts from an electrical enclosure, showing a tool being used to push out a circular metal piece from a pre-perforated hole.

Enclosure Mounting

Surface Mounting (Indoor and Outdoor)

Secure the enclosure to the wall with appropriate fasteners. Use all pre-cut holes in the back of the enclosure for mounting. See Figure 2.

Outdoor Mounting

1. Use the sealing gaskets provided if the mounting knockout locations shown in Figure 2 are used.
2. Use either one mounting hole at the top and two mounting holes at the bottom, or two mounting knockout holes at the top and two mounting holes at the bottom. See Figure 2.

Surface Mounting (General)

Temporarily position the enclosure with the centered tear drop hole. Secure the enclosure to the wall using the four mounting holes.

Figure 2: Surface Mounting. This figure shows an electrical enclosure with various mounting holes and knockouts, distinguishing between "Indoor" and "Outdoor" mounting configurations and indicating where fasteners should be placed.

Flush Mounting (Indoor Enclosure Only)

1. Remove the four small mounting knockouts on the side walls for securing to sixteen inch stud walls. See Figure 3.
2. Position the enclosure between studs so that the front edge is flush with the finished wall.
3. Secure the enclosure to the studs through the small knockouts. See Figure 3C.

Figure 3: Flush Mounting. This figure illustrates the process of flush mounting an enclosure. Panel A shows small knockouts on the side walls. Panel B shows the enclosure positioned between wall studs. Panel C shows screws securing the enclosure through these side knockouts into the studs.

Main Circuit Breaker or Main Lug Wiring

1. Pull the conductors into the enclosure. Use approved wire clamps, conduit bushings, or other approved methods to secure the conductor to the enclosure and prevent damage to the conductor insulation.
2. Connect the main and neutral wires.
   1. Install the main and neutral wires according to the wiring diagram on the load center.
   2. Connect the service ground, equipment grounding wire, or both as required by the local electrical code.
   3. Torque each connection to the value specified on the load center wiring diagram attached to the enclosure.
3. If required by the local code, install the enclosed green neutral bonding screw through the hole in the neutral bar. Thread the screw into the hole in the enclosure and torque to the value specified on the card shipped with the bonding screw.

Branch Circuit Breaker Installation and Removal

Standard and Tandem Branch Circuit Breakers—Installation

NOTE: Install QOT and HOMT tandem-type circuit breakers only in single-phase load centers marked for use with tandem circuit breakers. Refer to the wiring diagram on the load center for the installation location.

1. Determine the wiring or conduit requirements for the branch circuit.
2. Turn OFF (O) the circuit breaker. NOTE: For QOT CTL tandem only: hold the circuit breaker at 30–45° angle.
3. Install the wire terminal end of the circuit breaker onto the mounting rail.
4. Rotate the circuit breaker inward until the plug-on jaw fully engages the bus bar connector. Keep the bottom of the circuit breaker's case against the mounting rail. Check the terminal end of the circuit breaker for engagement to the mounting rail.
5. Remove the wire insulation from the branch wire as required. Install the branch wire into the load terminal of the branch circuit breaker.
6. Torque each branch circuit breaker connection to the value specified on the circuit breaker.
7. Torque each neutral and ground connection to the value specified on the load center wiring diagram attached to the enclosure.

Figure 4: QO Standard Circuit Breaker. This diagram shows a QO standard circuit breaker with labeled components: Wire terminal end, Plug-on jaw, Bus bar connector, and Mounting rail (plastic only).

Figure 5: QO Tandem Circuit Breaker. This diagram shows a QO tandem circuit breaker with labeled components: Wire terminal end, Plug-on jaw, Bus bar connector, and Mounting rail.

NOTE: Non-class CTL tandem circuit breaker shown. QOT class CTL tandem circuit breaker (not shown) cannot be installed on a plug-on neutral load center (metal mounting rail).

Removal

1. Turn OFF (O) the circuit breaker. Remove the wires.
2. To disconnect the plug-on jaw from the connector and mounting rail, lift the plug-on end of the circuit breaker until the circuit breaker jaw disconnects from the bus bar. Continue lifting until the terminal end disengages from the mounting rail. See Figure 4, 5, or 6 depending on circuit breaker type.

Installing the Cover / Trim

1. Remove the cover twistouts. Remove the appropriate twistouts to match the number of circuit breakers being installed. See Figure 8.
2. Attach the Spanish translation label, supplied with the load center, to the inside of the door or cover. See Figure 9.
3. Identify the circuit breakers on the directory label.
4. For service equipment, apply the "Service Disconnect" label(s) near the disconnect handle(s). If the main circuit breaker is installed and the device is used as a branch panel, apply the “Main” label to the trim near the main circuit breaker handle. See Figure 9.
5. Install the trim/cover using the screws provided and torque to 20 lbs-in. (2.3 N•m).
6. For QO outdoor load centers that are 150–225 A single-phase, main lug devices rated for 22,000 RMS symmetrical amperes short circuit systems, use four screws by removing the interior trim support bracket knockout. See Figure 9.
7. Fill any unused circuit breaker opening with the filler plates.

Figure 6: Homeline Standard Circuit Breaker. This diagram shows a Homeline standard circuit breaker with labeled components: Wire terminal end, Bus bar connector, Plug-on jaw, and Mounting rail.

Figure 7: Homeline Tandem Circuit Breaker. This diagram shows a Homeline tandem circuit breaker with labeled components: Wire terminal end, Bus bar connector, Plug-on jaw, and Mounting rail.

Figure 8: Remove Twistouts. This figure shows an enclosure cover with pre-scored circular sections (twistouts) that can be removed to accommodate circuit breakers.

Figure 9: Label Locations. This figure illustrates label placement locations on the enclosure for indoor and outdoor use, including Spanish labels, "Main" or "Service Disconnect" labels, door latch, interior trim support bracket knockout, and directory labels.

Energizing the Load Center

1. Before energizing the load center, turn off the main and all branch circuit breakers.
2. After power is turned on to the load center, turn on the main circuit breaker and then turn on the branch circuit breakers.
3. Rotate the door latch counterclockwise to allow engagement through the door slot (outdoor only).
4. Close the door until secured by the latch.