Alpha Technologies AMP24 HP - Manual (Page 12)

Doc. #: 0260011-J0 Rev B 10
1.5 Equipment Grounding
To provide a ready, reliable source of backup power, the power system must be connected to an
effective grounding and earthing system. The grounding system must be designed to protect both
personnel and equipment.
Low impedance grounding is mandatory for personnel safety, critical for the proper opera-
tion of the system, and must be in place and connected to the system before the supply
cables are connected.
1.5.1 Safety Ground
The safety ground is a two-part system – the utility service ground and the power system ground.
Utility Service Ground
As a minimum requirement for the protection of equipment, the local utility service must provide a
low-impedance path for fault current return to Earth. This must meet or exceed the requirements of
the US National Electrical Code or the Canadian Electrical Code.
Power System Ground
The power system ground consists of a low-impedance connection between the enclosure and an
Earth Ground, which must be located at least six feet away from the utility earth connection.
1.5.2 Lightning Strike Ground
Lightning strikes, grid switching, or other power surges on the power line and/or communications
cable can cause high-energy transients that can damage the power or communications systems.
Without a low-impedance path to the ground, the current will travel through wires of varying
impedance, which can produce damaging high voltages. The best method to protect the system
from damage is to divert these unwanted high-energy transients along a low-impedance path to the
ground.
See section "2.2 System Components" on page 13 for a description of the surge suppression modules
installed in the AMPS24 HP.
WARNING!