3Com 5000 well grounded. Otherwise, the router cannot reliably avoid lightning, Power Cord, Pgnd

Power Cords, Grounds and Cables 27

	Use a PGND wire to connect the screw to the earth ground, and the
	grounding resistance should not be greater than 5-ohm. Likewise, if the
	router is installed in a 19-inch standard rack, this rack is required to be
	grounded too.
	CAUTION: When the router is in normal operation, it is required to be
	well grounded. Otherwise, the router cannot reliably avoid lightning,
	which may damage the router itself and even the peer device.
Power Cord	The user is provided with two types of the Router 5000: AC-powered and
	DC-powered. Except for the input power, these two types have exactly
	the same features and functions.
Power input and
PGND	Table 10 Power input and PGND
	Item	Description
	Power input	Input voltage 12VDC, connected through the external power
		module to the 110/220V site power
	PGND	Connected to the earth ground with ground cable
	Table 11 Power input and PGND of other models
	Item	Description
	Power input	AC model: 100 to 240VAC power input socket
		DC model: -48 to -60VDC power input socket
	PGND	Connected to the earth ground with ground cable
AC Power Cord	AC power supply
	Rated voltage range: 100 to 240VAC, 50 Hz to 60 Hz.

The following figure illustrates the partial external appearance of the power socket for a AC-powered router: