What Size Portable Generator for 200 Amp Service

Guess what? People are now switching from 100 amp service to 200 amp electrical panels. And, generators can now be sized to suit 200 amp services also, and that even makes the whole detail an exhilarating one.

First off, know the size of a portable generator that will work explicitly for homes that use a 200 amp service. After all, portable generators have always been known to have a wattage capacity ranging from 800W to 20KW.

Standby generators can generate more wattage rates than portable ones, actually, and using any of its types for homes that require 200 amp services is so stress-free.

Technically, portable generators with high wattage won’t damage your appliances if you’re on 200 amp service. So, provided you will be using a high-power-generating generator, a 200 amp wiring will keep your circuits safe.

Besides, the US safety regulation emphatically stated that 80% of a 200 amp service should be utilized to avoid damages resulting from electrical trips and all sorts. So, what size portable generator for 200 amp service should you buy in the real sense?

Of course, high wattage from portable generators is not a factor with 200 amp panels. Instead, learn to adjust and upgrade the output of your generator to suit the service of a 200 amp panel below.

How Many Watts Do I Need for a 200 Amp Service?

Find out if the circuits you’ve got is a 120V or 240V. Now, imagine the circuits run on 120 voltage; then it is sure you’d be needing a generator that has a 48kw running capacity. There are a few calculations to ascertaining this, by the way.

Invariably, this implies that buying a portable generator, which has an overall wattage of 20kw, won’t damage the insertion of your electronic gadgets to any of your 120V power outlets. Provided you’re powering the likes of computers, fans, a coffee maker, washing machine, two industrial sewing machines, radios, and sensitive electronic gadgets.

The ultimate thing you’re to do is find out the wattage each requires. Some electronic appliances inscribe not in wattage but amperage. Use the Power = amps x voltage formula to draft out your result. It’s afterward that you can embark on immense calculations.

How to Calculate for the Needful Size of Portable Generator for Your 200 Amp Service?

Imagine the power required to power computers, fans, a coffee maker, a washing machine, and two industrial machines are 115w, 75w, 95w, 252w, 185w, and 44w, respectively. Let’s assume the previous wattage listed earlier in the respective running wattage of the pieces of equipment.

We are to check out the starting wattage of the following equipment likewise. We will be multiplying the running wattage of pieces of equipment that have motors by 1.5 to get their starting wattage. After that, the result sequence will be 0w, 0w, 145w, 378w, 277.5w, and zero watts for sensitive electronic gadgets.

The sum of the overall starting and running wattages is 800.5w and 766w. Sum the two together and what you’ll get is 1566w. We would need the reserve capacity of the overall wattage. We are to multiply the full load wattage by 0.25, and we get 391.5 for the reserve capacity.

Let’s add the reserve capacity with the full load; we will get 1957.5W. Invariably, we need a 2kw to power those pieces of equipment. Now, imagine we are powering twelve apartments. That simply means we would need a 24kw generator. So, you might need to learn to size your generator for 200 amp services now.

What Size Portable Generator for 200 Amp Service – 4 Factors

1. Voltage

The voltage of the circuit used could determine the expected wattage rate. Using a 240V for a generator power supply could prompt the need for generators with high wattage.

However, an inverter would enable the sizing of the generator to a desirable measure of 200 amp service. The inverter would convert circuits with DC voltage to AC voltage. So, you wouldn’t need to calculate your voltage as 240V but 120V.

Some generators enable users to change their voltage rate. They can reduce it and increase it. This would even reduce the consumption of fuel by the generator. Nonetheless, an expert’s expertise is needed to carry this out distinctly.

2. Transfer Switch

This stands as the intermediary between the utility power supply and generator to your house. There are different types of transfer switches anyways. But there are some with breaker boxes.

Those with breaker boxes enable users to pre-decide the circuits they are keen to power in their homes. There are switches representing each circuit in your home.

The moment you turn on the switches, power runs into the circuits they represent. You can run your calculations before turning on the control buttons in the breaker box to know the controls to turn on to size the distribution of power at the endpoint.

3. 15KW-20KW

Electricians believe that apartments that order the installation of 200amp panels use air conditioners, motor-operating units, heavy-duty electronics, and the rest. Therefore, they impugn homeowners to go for generators with running power capability ranging between 15kw and 20kw.

A 15kw, 16kw, and 17kw generator is recommended for homes with two or three mini-size air conditioners. Meanwhile, a 18kw, 19kw, 20kw is recommendable for homes that would use heavy-size appliances more than the usual one.

Typically, most homeowners use between 100amp and 160amp on most occasions, so they hardly reach a need for a 200 amp panel. Therefore, they are advised to choose a generator with its wattage range between the two rates.

4. Single-phase or 3-phase Power Distribution

The electrical distribution in the US is differentiated by single-phase and 3-phase power supplies. A single-phase power distribution has two wires and is often common in homes, while the three-phase has three wires, and each of the three wires can be relinquished to a single-phase AC power supply.

The differences can be fathomed from the runs from the transformer. Though the two can function between 120V and 240V, the 3-phase connections use 200 amp services more for consistency, while a 100 amp service is recommended for single-phase connections.

Obviously, generators with high power are recommended to a 3phase power supply that uses 200amp service.

How to Size a Generator Based on Amps?

List what you intend to power with a generator. Determine the voltage and find out the average also. In this case, the implementation of the Power = amps x voltage formula is still valid. Firstly, sum up the entire amperage you’ll need.

Divide the overall amps by two if you’re using a single-phase connection, and divide the overall amps by three if you’re using a three-phase connection. Multiply your result by the type of voltage you are keen on using to get the overall wattage you need from a generator.

What Should You Know Before Upgrading to 200-Amp Service?

It has immense benefits. However, 200amp isn’t mandatory if one never sees a need for its installation. Besides, it is a bit costly to install because one needs to hire the service of a licensed electrician. Moreover, its essence is inimitable if one plans to use industrial equipment and electronic appliances for the house. Of course, it’s usable in homes, hotels, restaurants, and conference halls.


  1. Its installation reduces electrical trips and maximizes consistency throughout the connected circuits.
  2. The wires running from one circuit to another won’t become overheated. It saves time and extra expenses when adding up circuits in the future.
  3. This lessens hazards caused by electrical dissipation both from utility sources and generator sources.
  4. You can bank the safety of your properties on this at any time.

Final Words

Now, you’ve understood that you can use generators that supply more power than 20W and less than 20W, but all the features should be considered. You won’t get it wrong if you adhere to the information here. Also, you can adjust the power supply of your generator with this.