How Many Solar Panels For (100, & 200 amp) Service

Last Updated: March 3, 2023

100 amp or 200 amp service is the electrical panel installed by your electricity provider. These panels manage the electricity flow coming from the grid to run household appliances safely.

I’m gonna share 2 simple steps to calculate the right size solar panel system for 100 amp or 200 amp service.

The size of the electrical panel will vary from 50-400 amp service but we’ll make the calculations for 100 amp & 200 amp which are the most common

In short, 100 amp service or electrical panel can handle 2400 watts or 2.4kWh solar power & 200 amp service breaker can handle 4.8 kWh or 4800 Watts of solar power.

These numbers define the wattage capacity but the 2.4kWh solar panel system will not produce 2.4kWh power. Which I’m gonna share in a moment.

Introduction to Amps, Volts, & watts

Amp (A): is defined as the number of electrons or current in simple words.
Volt (V): is defined as the speed or pressure of the current flow.
Watt (W) is the unit to measure the total power. (watts = Amps x Volts)

Watch: Volts, Amps, and Watts Explained

So we already know the value of amps, but how many voltages do electrical panels support? in most of the USA states the voltage coming from grid electricity will be 240 nominal volts because the electrical panel contains two 120V wires.

But our house outlets only support 120-120 volts (depending on your country and state’s electricity guide)

The solar panels are measured in watts and electrical panels or circuit boards are measured in amps so to make things simple let’s convert the amp into watts

Volts x Amps = Watts

Solar wattage required for 100 amp service calculation

240 x 100 = 2400 watts

Solar wattage required for 200 amp service calculation

240 x 200 = 4800 watts

So now there are a few things to keep in mind before calculating the size of solar panels which can generate this much power

How to calculate solar panel’s size for Amp service

Solar panels run at their 100% capacity under ideal sunlight conditions (Direct Sunlight, Right angel of the panels towards the sun) reference

So in short, you’ll not receive 100% from your solar panels all the time. On average you can expect 80% production from your solar panels on a shiny day.

This number can vary depending on weather conditions, your geographical location, and Season (summer or winter). So I live in Florida City and I receive 70-80% of my solar panels’ full capacity

So now simply add an extra 20% to values that we have calculated before (Solar wattage required)

How Many Solar Panels For 100 amp Service?

Amp service/electrical panel voltage = 240-Volts

Electrical panel Amps = 100 amps

240*100 = 2400 watts + 20% = 2880 Watts of solar panels

You can connect a 3kW solar system with 100 amp service or 10 300-watt solar panels

How Many Solar Panels For 200 amp Service?

Amp service/electrical panel voltage = 240-Volts

Electrical panel Amps = 200 amps

240*200 = 4800 watts + 20% = 5760 Watts of solar panels

You can connect a 6kW solar system with 200 amp service or 20 300 watts of solar panels

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Chris Tsitouris

Chris Tsitouris is a renewable energy professional with 10+ years of experience as Director of Engineering at Solar Spectrum, previously working as Project Manager at SunPower and Energy Analyst at the National Renewable Energy Laboratory. As a thought leader, Chris has authored numerous articles and research papers.