Generators For Home Use

Frequently Asked Questions

This page contains questions about generators for home use.

Some questions will include the less mobile standby generators, and others will concern portable generators...all fuel types.

Can you explain the difference between single phase and three phase?

Single phase is a type of voltage supply in which the there are is only one supply line and a ground line. There is only one voltage which varies sinusoidally. In three phase the supply is through three supply wires and a ground wire.

Single phase is generally used for lighting and heating purposes. Motors above 10kW are generally not run on single phase supply. Single phase motors also require extra starter circuits.

You can find out the supply you receive by looking at your main circuit breaker. In case you are still unsure have an electrician take a look.

How are generator decibel levels calculated?

Most of the famous brands mention the noise output at full load. It would be useless to know the decibel levels unless you are able to compare them to values you would know.

Normal speech is at about 60dB. A difference of 5dB would not be discernible. Residential generators should perform at about 64dB to 68dB.

The standard distance expected between you and the generator is 21 feet according to US standards and 23 feet according to EU standards. The enclosure, air flow and noise insulation play the main role in deciding noise levels. Be sure to run the generator at full output before checking the noise level.

What it comes to a diesel engine, what does the term "wet stacking" mean?

Generally when a diesel engine runs much below its rated output i.e. at about 40% to 50%, the fuel is not burnt completely and this passes on to the turbocharger. Operating a diesel engine with less load for prolonged periods causes the unburnt excess fuel to carbonize the various parts on the exhaust side.

This disrupts the fuel spray pattern by carbonizing the fuel injection tips. This can be remedied by running the engine at full output for a couple of hours. This will burn out the excess fuel.

Do 1800 RPM diesel generators last longer than 3600 RPM GenSets?

1800 RPM generators mostly outlast the 3600 RPM ones under similar conditions of operation. A liquid cooling option will prolong the life of a generator over an air cooled one. For a long life choose a lower RPM generator with liquid cooling option.

What size of generator do I need for a home or small business?

Picking a generator is to be done by calculating your needs. While most sensitive equipment like computers use lesser power, equipment like air conditioners, well pumps and refrigerators use a lot of power.

An average household would require about 140 Amps to 160 Amps. Therefore it is easy to calculate your power need by multiplying the current per device with its operating voltage.

For example refrigerator rated at 20Amps/120V would require 20×120=2400Watts.

Thus calculating the wattage of generators for home use will give an approximate value of the power needed. One thing to be remembered is that most of the equipment are rated to their peak values and their actual working values will be around 15% lesser. Also to be noted is whether all your appliances will be running at the same time.

A safe approximation would be as follows:

For a 100 Amp service panel pick a generator about 8-12kW.

For 200 Amp service panel pick a generator about 15-20kW and for a 400Amp service panel choose a 30-50kW generator. Depending upon the equipment pick the values in the range.