General Information - Siemens Standby Generators Manual

Generator Sizing Guide

General Information

Important Notice
This booklet is designed to familiarize estimators and installers
with proper sizing guidelines for residential and commercial
generators. The information is not comprehensive, nor does
it replace or supercede any material contained in any of
the written documents shipped with the equipment. This
booklet should only be used in conjunction with the Owner's
Manual, Installation Manual and other technical documents
shipped with each product. Always read all accompanying
documentation carefully before attempting to install any
generator, transfer switch or related equipment.
How to Use this Booklet
Within this booklet, you will find electrical load information,
plus an outline of generator surge capability, fuel pipe sizing,
liquid propane tank sizing, and UPS / generator compatibility.
The final pages are perforated for easy removal and can be
photocopied to create additional Onsite Estimating Sheets
for use with individual jobs.
Safety Information
Proper sizing of the generator is crucial to the success of
any installation and requires a good working knowledge
of electricity and its characteristics, as well as the varying
requirements of the electrical equipment comprising the load.
When analyzing the electrical load, consult the manufacturer's
nameplate on each major appliance or piece of equipment
to determine its starting and running requirements in terms
of watts, amps and voltage. When choosing the generator
output for commercial or industrial applications, select a
rating that is approximately 25% higher than the peak load
(for example, if the load is about 40 kilowatts, select a 50 kW
genset). A higher rated generator will operate comfortably
at approximately 80% of its full capacity and will provide a
margin of flexibility if the load increases in the future.
For safety reasons, Siemens recommends that the backup
power system be installed, serviced and repaired by a
Generac Authorized Service Dealer or a competent,
qualified electrician or installation technician who is
familiar with applicable codes, standards and regulations.
It is essential to comply with all regulations established by
the Occupational Safety and Health Administration (OSHA)
and strict adherence to all local, state and national codes
is mandatory. Before selecting a generator, check for
municipal ordinances that may dictate requirements
regarding placement of the unit (setback from building
and/or lot line), electrical wiring, gas piping, fuel storage (for
liquid propane or diesel tanks), sound and exhaust emissions.
If you have a technical question regarding sizing or
installation, contact Siemens Technical Service Center
toll free at 800-844-0029 during normal business hours
(8 a.m. to 5 p.m. CST).
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