Generac Power Systems Transfer Switches and Accessories How Much Power Do You Need?, Sizing Guide

How Much Power Do You Need?

Whole-House Protection

Generac offers air-cooled and liquid-cooled generators that can supply up to whole-house protection. In conjunction with a transfer switch, this application completes your power solution package (see page 8 for options).

To accurately size liquid-cooled generators, a licensed electrician should apply an Amp meter to the circuits and appliances to determine the load requirement for back up.

Sizing Guide

Air Cooled Generator	8 kW	10 kW	14 kW	17 kW	Circuits	20 kW
5-Ton Central Air 1					(50 Amp / 240V)2
4-Ton Central Air 1					(40 Amp / 240V)2
3-Ton Central Air 1	•				(30 Amp / 240V)2
Well Pump or Water Heater					(20 Amp / 240V)2
Family Room					(20 Amp / 120V)
Master Bedroom					(20 Amp / 120V)	Whole-
Home Office					(20 Amp / 120V)
Media Room					(20 Amp / 120V)	house
Garage					(20 Amp / 120V)
Bathroom					(15 Amp / 120V)	Protection
Kitchen (#1)3					(20 Amp / 120V)
Kitchen (#2)3					(15 Amp / 120V)
Furnace					(15 Amp / 120V)
Sump Pump					(15 Amp / 120V)
Bedroom (#2)					(15 Amp / 120V)
Bedroom (#3)					(15 Amp / 120V)
Bathroom (#2)					(15 Amp / 120V)

1Check your air conditioner’s starting requirements. Starting requirements for older and/or less efficient equipment may exceed recommended generator capability. Additionally, for any electrical equipment or appliances, always check the manufacturer’s power requirements. This will help to ensure standby power accommodations for items that cycle during operation.

2 240 volt appliances require 2 circuits 3 Most kitchens require multiple circuits

•For smaller central air up to 2 tons

Note: Rooms and appliances indicated here are for example only. You may choose others that better reflect your needs. Because of the cycling nature of some appliances such as refrigerators and furnaces, it may not be possible for all appliances to run simultaneously.

Transfer switch configurations

Automatic Transfer Switch Basic

RTS-E models

RTS-S models

RTS-N models

Automatic Transfer Switch Basic is rated NEMA 1. All RTS-N, RTS-E & RTS-S transfer switches are NEMA 3R (outdoor/ indoor) rated.

Note: Warranty coverage is not available for generators that are used for prime power (main power source) in place of the existing utility power where utility power is present or in place of utility power where utility power service does not normally exist. For life support or critical care applications, please see page 6 for industrial units.

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