Emergency Circuit Isolation Method

Installation

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

Critical electrical loads are grouped together and wired into asepa- rate "Emergency Distribution Panel." Load circuits powered by that panel are within the wattage/amperage capacity of the generator set. When this method is used, it is difficult to overload the gen-

erator, The transfer switch must meet the

requirements:

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

•Have it installed between the building'smain distribution panel and the emergency distribution panel.

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 generator 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	the ampere
rating of the normal incoming utility service,

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

GROUNDING THE GENERATOR

The generator set must be grounded in accordance with the National Electrical Code and any state or local requirements,

ADo not connect the ground wire to any pipe ~that carries a flammable or explosive sub-

stance - FIRE or an EXPLOSION may result.

Figure 2.2 - Grounding Electrode Terminal (typical)

Base Frame

Grounding Electrode Terminal

GENERATOR AC NEUTRAL

CONNECTIONS

Grounding is recommended only at one point in the system, Consult local building codes for proper neutral grounding require- ments,

TRANSFER SWITCH START SIGNAL CONNECTIONS

If the generator is to be installed with a standard automatic transfer switch, such as a GTS type switch, it will be 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 lower rear of the AC connection panel. Match wires 178 (0) and 183 In the transfer SWitch to 178 (0) and 183 on the terminal strip In the connection box, The conductors for the two-wire start circuit must be in their own conduit.

If the generator is to be installed with an HTS-type transfer switch a different connection method is needed, Use shielded 2-wir~communications cable (such a Belden #9460) to make the con- nection from the HTS transfer switch to the engine generator connection panel. This cable is to be routed in a separate conduit between the HTS transfer switch and the generator, The cable is to be connected as follows:

HTS transfer switch - 4 position terminal block, in the bottom of the transfer switch enclosure (labeled "comm, Ports"),

Engine generator - terminal strip located in the lower rear of the AC connection panel. Connect the RS485+ and RS485- to the respective terminals in switch and generator. Do not connect the shield at the transfer switch end.

BATTERY INSTALLATION

AStationary emergency generators installed

.... with automatic transfer switches will crank and start automatically when NORMAL (UTIL- ITY) source voltage is removed or is below an acceptable preset level. To prevent such automatic start-up and possible injury to per- sonnel, do not connect battery cables until certain that normal source voltage at the transfer switch is correct and the system Is ready to be placed Into operation.

AStorage batteries give off explosive hydrogen ~gas. This gas can form an explosive mixture

around the battery for several hours after charging. The slightest spark can ignite the gas and cause an explosion. Such an explo- sion can shatter the battery and cause blind- ness or other injury. Any area that houses a storage battery must be properly ventilated. Do not allow smoking, open flame, sparks or any spark producing tools or equipment near the battery.