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This appendix describes how to make DC power connections to the Catalyst 3750G-12S-SD switch. See the "Installing the Switch" section for instructions on installing the switch.
To connect the Catalyst 3750G-12S-SD switch to a DC-input power source, follow the steps in these sections:
•Wiring the DC-Input Power Source
Note We recommend that you use 18 AWG copper wiring for Network Equipment Building Systems (NEBS) installation. This guideline follows the standard guidelines for DC power wiring in the Central Office.
Note The grounding architecture of this product is DC-isolated (DC-I).
Locate the ground lug and the two number-10-32 screws on the switch rear panel and the DC terminal block plug in the DC-switch accessory kit.
Obtain these necessary tools and equipment:
•Ratcheting torque screwdriver with a Phillips head that exerts up to 15 pound-force inches (lbf-in.) or 240 ounce-force inches (ozf-in.) of pressure
•Panduit crimping tool with optional controlled cycle mechanism (model CT-700, CT-720, CT-920, CT-920CH, CT-930, or CT-940CH)
•6-gauge copper ground wire (insulated or noninsulated)
•Four leads of 18-gauge copper wire
•Wire-stripping tools for stripping 6- and 18-gauge wires
To ground the switch to earth ground, follow these steps. Make sure to follow any grounding requirements at your site.
Step 1 Locate and remove the ground lug and the two number-10-32 ground-lug screws from the rear panel of the switch. (See Figure C-3 for location.) Use a standard Phillips screwdriver or a ratcheting torque screwdriver with a Phillips head. Set the screws and the ground lug aside.
Step 2 If your ground wire is insulated, use a wire stripping tool to strip the 6-gauge ground wire to 0.5 inch (12.7 mm) ± 0.02 inch (0.5 mm), as shown in Figure C-1.
Figure C-1 Stripping the Ground Wire
Step 3 Slide the open end of the ground lug over the exposed area of the 6-gauge wire.
Step 4 Using a Panduit crimping tool, crimp the ground lug to the 6-gauge wire, as shown in Figure C-2.
Figure C-2 Crimping the Ground Lug
Step 5 Use the two number-10-32 screws to attach the ground lug and wire assembly to the switch rear panel ground connector, as shown in Figure C-3.
Step 6 Using a ratcheting torque screwdriver, torque each ground-lug screw to 15 lbf-in. (240 ozf-in.)
Use either the front ground connector or the rear ground connector. You cannot use both at the same time.
Figure C-3 Torquing Ground-Lug Screws
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Torque to 15 lbf-in. |
Warning Before performing any of the following procedures, ensure that power is removed from the DC circuit. Statement 1003 |
Warning This product relies on the building's installation for short-circuit (overcurrent) protection. Ensure that the protective device is rated not greater than: 5 A Statement 1005 |
Warning Only trained and qualified personnel should be allowed to install, replace, or service this equipment. Statement 1030 |
Note This installation must comply with all applicable codes.
To wire the switch to a DC-input power source, follow these steps:
Step 1 Apply tape to the circuit-breaker switch handle, and move the circuit-breaker handle to the off position.
Step 2 Locate and remove the terminal block plug (see Figure C-4).
Figure C-4 Terminal Block Plug
Step 3 Identify the positive and negative feed positions for the terminal block connection. The wiring sequence is positive to positive and negative to negative for both the A and the B feed wires. The switch rear panel identifies the positive and negative positions for both the A and B feed wires, as shown in Figure C-5.
Figure C-5 Positive and Negative Positions on the Switch Rear Panel
Step 4 Using a 18-gauge wire-stripping tool, strip each of the four wires coming from the DC-input power source to 0.27 inch (6.6 mm) ± 0.02 inch (0.5 mm), as shown in Figure C-6. Do not strip more than 0.29 inch (7.4 mm) of insulation from the wire. Stripping more than the recommended amount of wire can leave exposed wire from the terminal block plug after installation.
Figure C-6 Stripping the DC-Input Power Source Wire
Step 5 Insert the exposed wire of one of the four DC-input power source wires into the terminal block plug, as shown in Figure C-7. Make sure that you cannot see any wire lead. Only wire with insulation should extend from the terminal block.
Figure C-7 Inserting Wires in the Terminal Block Plug
Step 6 Use a ratcheting torque screwdriver to torque the terminal block captive screw (above the installed wire lead) to 4.5 lbf-in. (72 ozf-in.), as shown in Figure C-8.
Figure C-8 Torquing the Terminal-Block Captive Screws
Step 7 Repeat Steps 4 and 5 for the remaining three DC-input power source wires. Figure C-9 shows the completed wiring of a terminal block plug.
Figure C-9 Completed Wiring of Terminal Block Plug
Step 8 Insert the terminal block plug in the terminal block header on the switch rear panel, as shown in Figure C-10.
Figure C-10 Inserting the Terminal Block in the Block Header
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Tie wrap |
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Terminal block |
Step 9 Remove the tape from the circuit-breaker switch handle, and move the circuit-breaker handle to the on position.