T640 Chassis Grounding Cable and Lug Specifications

To meet safety and electromagnetic interference (EMI) requirements and to ensure proper operation, the T640 router must be adequately grounded before power is connected. Two pairs of threaded inserts (PEM nuts) are provided on the right rear of the chassis for connecting the router to earth ground.

Caution: Before router installation begins, a licensed electrician must attach a cable lug to the grounding and power cables that you supply. A cable with an incorrectly attached lug can damage the router.

To ground the router, connect a grounding cable to earth ground and then attach it to the chassis grounding points using two screws. The left pair of grounding points fits M6 screws (European), and the right pair fits UNC 1/4–20 screws (American). The grounding points are spaced at 0.625-in. (15.86-mm) centers. The accessory box shipped with the router includes the cable lug that attaches to the grounding cable (see Figure 1) and two UNC 1/4–20 screws used to secure the grounding cable to the right pair of grounding points. (The cable lug shown in Figure 1 is also used for the DC power cables.) The grounding cable must be able to handle up to 152 A. The accessory box shipped with the router includes the cable lug that attaches to the grounding cable (see Figure 1).

Figure 1: T640 DC Power and Grounding Cable Lug

The grounding cable must be 4-AWG (21.2 mm²), minimum 90°C wire, or as required by the local code.