a grounding pad with two system (earth) grounding holes is provided in an enclosure near the left power supply on the catalyst 4500 series switches. see figure 3-13 for the location of the grounding holes on the catalyst 4503 switch,figure 3-14 for the location on the catalyst 4506 switch, figure 3-15 for the location on the catalyst 4507r switch, and figure 3-16 for the location on the catalyst 4510r switch.