Connecting Power to the Router

Connect power to the router by attaching a grounding cable to the chassis grounding points and attaching power cables from external power sources to the terminal studs on the circuit breaker box. Power and grounding cables are not supplied with the router. For cable specifications, see Power, Connection, and Cable Specifications.

The router must be connected to at least two separate external power sources.

There is no standard color coding for DC power cables. The color coding used by the external DC power source at your site determines the color coding for the leads on the power cables that attach to the terminal studs on the circuit breaker box. You must ensure that power connections maintain the proper polarity. The power source cables might be labeled (+) and (–) to indicate their polarity.

To connect power to the router, follow this procedure (see Figure 60):

1. Verify that there is no power flowing from either external power source, so that the voltage across the leads of the power cables is 0 V. Ensure that there is no chance that the cable leads might become active during the procedure.
2. For each power supply, verify that the power switch on the circuit breaker box is in the OFF (O) position.
3. Connect the grounding cable to a proper earth ground.
4. Verify that a licensed electrician has attached the cable lug provided with the router to the grounding cable.
5. Place the grounding cable lug over the grounding points on the bottom rear of the chassis. The grounding points are sized for 1/4-20 UNC screws.
6. Secure the grounding cable lug to the grounding points, first with the washers, then with the screws.

   Do not substitute metric screws such as M6 for the 1/4-20 UNC screws that screw into the grounding points; screws other than 1/4-20 UNC screws can strip the threading in the grounding points.

7. Using a Phillips screwdriver, loosen and remove the screws securing the protective shield over the terminal studs on the circuit breaker box. Remove the cover.
8. Install one nut and one flat washer (in that order) on each power terminal stud:
   • If no washers and nuts are already installed, they should be in the accessory box.
   • If two pairs of nuts and washers are installed on the studs, use a 7/16-in. nut driver or wrench to loosen the outer nut on each stud. Remove the outer nuts and washers, leaving the inner nut and washer on each stud.

     Do not substitute a metric nut driver or wrench. A tool that does not fit the nuts exactly can damage them. If a 7/16-in. tool is not available, use pliers or an adjustable wrench.

     The inner washer and nut prevent direct contact between the power cable lug and the circuit breaker box, which can cause a short circuit.

9. Slide the power cable lugs onto the terminal studs:
   • Connect the positive (+) source cable lugs to the return terminals, which are labeled RTN(+).
   • Connect the negative (–) source cable lugs to the input terminals, which are labeled –48V.
10. Install another washer and nut (in that order) on each terminal stud to secure the power cable lug. Using a 7/16-in. nut driver or wrench, tighten the nuts.
11. Verify that the source power cabling and the grounding cabling are correct, that they are not touching or blocking access to router components, and that they do not drape where people could trip on them.
12. Replace the protective shield over the terminal studs and use a Phillips screwdriver to tighten the screws.