Generac Power Systems 004988-1 2.6TOTAL CIRCUIT ISOLATION METHOD, 2.7GROUNDING THE GENERATOR

Section 2 — Installation

Guardian Liquid-cooled 27 kW and 30 kW Generators

•It must have an ampere rating equal to 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.

2.6TOTAL 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 equal the ampere rating of the normal incoming utility service.

•The transfer switch is installed between the utility service entrance and the building distribution panel.

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

Figure 2.2 – Generator Grounding Lug (typical)

GROUNDING

LUG

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 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.

2.8GENERATOR AC NEUTRAL

CONNECTIONS

Generac uses an UNGROUNDED AC neutral. 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.

2.9TRANSFER SWITCH SIGNAL CONNECTIONS

‹2.9.1 PRE-PACKAGED ATS

If the generator is to be installed with a pre-packaged transfer switch, it is necessary to connect the control wires to the generator and set position two of the four-position dip switch to OFF.

Setting switch two to OFF allows the control PCB to perform the ATS control functions.

Control system interconnections consist of N1 and N2, and leads 23 and 194. Control system intercon- nection leads must be run in a conduit that is sepa- rate 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	RECOMMENDED WIRE
	SIZE
460 feet (140m)	No. 18 AWG.
461 to 730 feet (223m)	No. 16 AWG.
731 to 1,160 feet (354m)	No. 14 AWG.
1,161 to 1,850 feet (565m)	No. 12 AWG.

‹2.9.2 GTS-TYPE ATS

If the generator is to be installed with an automatic transfer switch, such as an engineered Generac GTS- type switch, it is necessary to connect the two-wire start control system.

Connect the two-wire start signal from the automatic transfer switch to the automatic start connection, which is located in the middle, on the bottom, inside the control panel. Match wires 178 and 183 in the transfer switch to 178 and 183 on the terminal strip in the control panel. The conductors for the two-wire start circuit must be in their own conduit. (See Section 3.1 for further explanation.)

10 Generac® Power Systems, Inc.