1�6 Equipment Grounding - Alpha Technologies AMPS HP2 Power System Installation & Operation Manual

WARNING!
Multiple power inputs: disconnect all inputs before servicing to avoid electric shock.
• AMPS-3-75 and AMPS-2-40 UPS are rated for use on a circuit capable of delivering no more than 10 KA rms
symmetrical amperes, 120V maximum.
• AMPS-3-30, AMPS2-20 and AMPS-1-10 UPS are rated for use on a circuit capable of delivering nor more
than 5 KA rms symmetrical amperes, 120V maximum.
1.6 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 equip-
ment.
WARNING!
High leakage current. Earth connections essential before connecting power supply.
Low impedance grounding is mandatory for personnel safety, critical for the proper
operation of the system, and must be in place and connected to the system before
the supply cables are connected.
1.6.1 Safety Ground
The safety ground is a two-part system – the utility service ground and the power system ground.
Utility Service Ground
WARNING!
Risk of electric shock. The UPS equipment powered by this service panel requires
the neutral to be bonded to ground. Disconnect the UPS DC batteries before servic-
ing the panel.
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.
1.6.2 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 unwanted high-energy transients along
a low-impedance path to the ground. See 8.6 for information on the surge suppression modules installed in the
AMPS HP2.
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