Table of Contents
Advertisement
2.5
EMERGENCY CIRCUIT ISOLATION
METHOD
This prevents overloading the generator by keeping
electrical loads below the wattage/amperage capacity
of the generator. If the generator is powering only crit-
ical loads, within the wattage/amperage capacity, dur-
ing utility power outages, consider using the emer-
gency circuit isolation method.
Critical electrical loads are grouped together and
wired into a separate "Emergency Distribution
Panel." Load circuits powered by that panel are with-
in the wattage/amperage capacity of the generator set.
When this method is used, it is difficult to overload
the generator. The transfer switch must meet the fol-
lowing requirements:
• It must have an ampere rating equal to, or greater
than, the total amperage rating of the emergency
distribution panel circuit.
• Have it installed between the building's main dis-
tribution panel and the emergency distribution
panel.
2.6
TOTAL CIRCUIT ISOLATION
METHOD
When a generator capable of powering all electrical
loads in the circuit is to be installed, use the "Total
Circuit Isolation Method." It is possible for the gener-
ator to be overloaded when this isolation method is
employed. The following apply to the transfer switch
in this type of system.
• Ampere rating of the transfer switch must be equal
to, or greater than, the ampere rating of the normal
incoming utility service.
• The transfer switch is installed between the utility
service entrance and the building distribution
panel.
2.7
GROUNDING THE GENERATOR
The National Electrical Code requires the frame and
external electrically conductive parts of this equip-
ment to be properly connected to an approved earth
ground and/or grounding rods. For that purpose, a
GROUND LUG (Figure 2.2) is provided on the gener-
ator mounting base. Consult a qualified electrician
for grounding requirements in the area. Grounding
procedures must meet local regulations.
DANGER
Do not connect the ground wire to any pipe
that carries a flammable or explosive substance
– FIRE or an EXPLOSION may result.
10 Bryant
Section 2 — Installation
Bryant Liquid-cooled 15 kW Generators
Proper grounding helps protect personnel against
electrical shock in the event of a ground fault condi-
tion in the generator or in connected electrical
devices. In addition, grounding helps dissipate static
electricity that often builds up in ungrounded
devices.
Figure 2.2 – Generator Grounding Lug (typical)
2.8
GENERATOR AC NEUTRAL
CONNECTIONS
Bryant
uses
an
UNGROUNDED
Grounding is recommended only at the main service
entrance. If the neutral wire is grounded and one of
the phase loads becomes grounded, the excessive
current opens the load circuit breaker or collapses
the generator field. The actual result depends on the
electrical characteristics of the particular installed
generator.
Failure to connect the generator neutral prop-
!
erly will result in unbalanced line-to-neutral
voltages. Resulting high voltages will cause
equipment damage.
2.9
TRANSFER SWITCH SIGNAL
CONNECTIONS
It is necessary to connect the control wires between
the generator and the transfer switch.
Control system interconnections consist of N1, N2,
T1, T2 and leads 23 and 194. Control system inter-
connection leads must be run in a conduit that is sep-
arate from the AC power lead. Recommended wire
gauge sizes for this wiring depends on the length of
the wire, as recommended below:
MAXIMUM WIRE LENGTH
460 feet (140m)
461 to 730 feet (223m)
731 to 1,160 feet (354m)
1,161 to 1,185 feet (565m)
AC
neutral.
RECOMMENDED WIRE
SIZE
No. 18 AWG.
No. 16 AWG.
No. 14 AWG.
No. 12 AWG.
Advertisement
Table of Contents
