2.5EMERGENCY CIRCUIT ISOLATION

Section 2 — Installation

Liquid-cooled 25 kW Generators

2.5EMERGENCY CIRCUIT ISOLATION

METHOD

This prevents overloading the generator by keeping electrical loads below the wattage/amperage capac- ity of the generator. If the generator is powering only critical loads, within its wattage/amperage capac- ity, during utility power outages, consider using the emergency circuit isolation method.

Critical electrical loads are grouped together and wired into a separate “Emergency Distribution Panel.” The generator only supplies electrical circuits con- nected to the emergency distribution panel during utility power outages. Load circuits powered by that panel must be within the wattage/amperage capacity of the generator set. The transfer switch must meet the following requirements:

It must have an ampere rating equal to the total amperage rating of the emergency distribution panel circuit.

It must be installed between the building’s main distribution panel and the emergency distribution panel.

2.6TOTAL CIRCUIT ISOLATION

METHOD

When a generator capable of powering all electri- cal loads in the circuit is to be installed, the “Total Circuit Isolation Method” may be used. The following apply to the transfer switch in this type of system.

Ampere rating of the transfer switch must equal the ampere rating of the normal incoming utility service.

The transfer switch is installed between the util- ity service entrance and the building distribution panel.

2.7GROUNDING 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 gen- erator mounting base. Consult a qualified electrician for grounding requirements in the area. Grounding procedures must meet local regulations.

2.6TOTAL CIRCUIT ISOLATION2.7GROUNDING THE GENERATOR DANGER

Do not connect the ground wire to any pipe that carries a flammable or explosive substance

– FIRE or an EXPLOSION may result.

Proper grounding helps protect personnel against elec- trical shock in the event of a ground fault condition 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)

2.8GENERATOR AC NEUTRAL

CONNECTIONS

The manufacturer uses an UNGROUNDED AC neu- tral. Grounding is recommended only at the main service entrance. If the neutral wire is grounded and one of the phase loads becomes grounded, the exces- sive current opens the load circuit breaker or col- lapses the generator field. The actual result depends on the electrical characteristics of the particular installed generator.

Failure to connect the generator neutral proper- ly will result in unbalanced line-to-neutral volt- ages. Resulting high voltages will cause equip- ment damage.

2.9USING A “GTS” TRANSFER

SWITCH

When required, the pre-packaged standby generator can be installed with a “GTS” type engineered auto- matic transfer switch.

In this application, the GTS transfer switch is responsible for utility sensing, weekly exercising, and load transferring.

Position two of the eight-position DIP switch is used to turn over this control to the GTS.

In order for the battery charger to work, it is neces- sary to provide a fused 240 VAC utility source to the N1 and N2 terminals in the control panel.

Pos2 ON — GTS Application

The control board will NOT monitor utility.

The control board will NOT perform a weekly exer- cise. (The five red LEDs will flash one at a time in this mode.)

The control board will NOT activate the transfer output.

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Generac 005031-2 2.5EMERGENCY CIRCUIT ISOLATION METHOD, 2.6TOTAL CIRCUIT ISOLATION METHOD, 2.7GROUNDING THE GENERATOR