Chapter 3 Pre-Installation
Gen 3 Site Controller System Manual
Grounding Requirements
3-18
68P80801E30-A 5/1/2002
CAUTION
CAUTION
!
Electrical System Grounding
The site electrical system should be connected to the master ground bar by a
single connection. This should be from the panel/sub-panel in the equipment
room with a #2 AWG stranded green insulated wire. For sites with
sub-panels, the utility green Multi-Grounded Neutral (MGN) wire may not
be present. In this situation, an electrician may need to be consulted to
extend the MGN from the service entrance to the sub-panel. If this is done in
metal conduit, then grounding clips should be used at both ends of the
conduit to minimize inductance.
If metal conduit is used for the electrical system, all connections must be
bonded together through conduit compression or screw fittings designed for
such purposes. The metal conduit system must not be in contact with other
metal on the site, including cable ladder or equipment cabinets, to minimize
ground loops and sharing of surge energy. Small pieces of rubber or other
insulating material may be used on conduit clamps to eliminate any
inadvertent connections.
NEC PROHIBITS GROUNDING THE AC POWER SYSTEM
NEUTRAL (WHITE WIRE) ANYWHERE OTHER THAN AT THE
SERVICE ENTRANCE PANEL. HOWEVER, GROUNDING OF
THE MGN (GREEN WIRE) AT MULTIPLE LOCATIONS IS
ALLOWED.
ENSURE A GOOD CONNECTION BETWEEN THE
ELECTRICAL SYSTEM GROUND AND SITE GROUND TO
PREVENT EXCESSIVE VOLTAGE POTENTIAL BETWEEN THE
TWO GROUND SYSTEMS DURING LIGHTNING STRIKES.