John Smith is a homeowner in California looking to reduce his electric bill by going solar and he decided to call an installation company that he found on the internet.
The next day, a rep from XYZ Solar came out to his house and, after looking at his electric bill, told John that he would need an 8.5kW PV system to offset 100% of his past 12-month usage.
The economics made sense and shortly thereafter the rep walked around to the side of the house and snapped a couple of photos of the main service panel.
We covered Main Panel Upgrades in Pick My Solar LIVE! Patrick and Kyle share a full look into how to determine if a breaker upgrade is necessary for your solar project.
Two days later, John received a call from the same rep and was told that, unfortunately, the main panel upgrade would be required, adding an additional $2,000 to the cost of the project.
When the rep tried to explain why an upgrade would be necessary, the explanation made much less sense. In fact, it made no sense at all when the rep told John, “Normally, an upgrade would not be necessary, but your main service panel is center-fed, which is why an upgrade – in your case – is required”.
In many cases, a homeowner could be spared the $2K expense if the installation company were to perform a simple load calculation to determine whether or not de-rating the main breaker is possible, safe, and passable by city inspectors.
For John’s project, a 7600W string inverter is being proposed by the installation company – a good choice, and the spec sheet shows 40 amps of back-feed protection is required by the main service panel in order for this inverter to be connected. Now, John looks at the sticker on the inside door of his main service panel box, which says 200A. The main breaker switch also says 200A.
But how can John figure out the amount of back-feed protection available on his main service panel?
A simple formula is as follows: 200A buss bar (as shown on the sticker) X 120% = 240. Then, take 240 minus 200 (main breaker) = 40A. Since we need 40A of back-feed protection, we are good to go.
Check out this video to understand the amps of your panel box
Project aspects like this might sound slightly complicated, which was why Solar was founded – to ensure the consumer is protected when technical aspects of projects are laid out.
We play the role of homeowner’s advocate to make sure there’s always an unbiased solar expert to bounce questions off of.
U.S. Installed Solar Capacity: 2 Million Milestone
According to the most recent data released by Wood Mackenzie Power & Renewables and the Solar Energy Industries Association (SEIA), the residential solar market in...
Solar Subcontractors: Should I use one to go solar?
So, youre interested in starting a solar project and now youre wondering, “who should be doing the installation work?” Well, more and more companies are...
5 Most Popular Solar Panels Chosen by Homeowners in 2018
Homeowners demand a lot from the solar panels they select for their rooftop system. These panels need to look good and perform well over multiple decades! Here are...
According to Indian Prime Minister Narendra Modi, India is on track to install 200 gigawatts of renewable capacity by 2020. The country is fully embracing...
If you live in an area that experiences extreme weather like hurricanes, hail, thunderstorms, blizzards, heavy winds and more, then you should take the time...
If you have ever driven through a residential neighborhood in states like California, Arizona, North Carolina, or any of the other top states for solar,...
Hyundai and Panasonic are trusted brands and they’ve both expanded into the solar panel industry. Offering quality products for two different price points, each brand...
Should I Get a Solar Thermal System Instead of a PV System?
When you hear about installing solar, youre most likely hearing about PV (photovoltaic) solar cell panels. Theyve become standard in the industry. PV solar cell...
How Utility API Works With Your Utility and Solar Company
Utility API provides software to accelerate the clean energy movement. They do this, in part, by offering secure data on a homeowners energy usage to...
American Solar Panel Manufacturers - 2018 Complete List
There are many reasons why a consumer may want to purchase their solar panels from an American manufacturer or from American Solar brands. They want...
Household solar monitoring systems change the abstracts of power generation and consumption into graphics and numbers you can scroll through on an app. Hardware...
Solar panel mounts are a common component of almost every solar panel array. Although there are newer solar panel technologies coming out that do not...
Top 5 Solar Panels Selected Through Solar.com in 2017
Curious which solar panels are selected most on the Solar.com platform? As an online marketplace connecting quality solar companies to customers, we stay neutral toward...
SunPower Solar Panels vs. LG Solar Panels - 2018 Update
SunPower and LG are two of the top companies making solar panels. Youve probably come across them in your research, and youre wondering which will...
Solar panels and backup batteries get all the attention. But there’s another important piece of equipment to the home solar equation: mounting systems. These sturdy...
Solar technology has been in existence since 1876 when William Grylls Adams and his student researcher discovered that you can produce electricity by exposing selenium to...
Solar energy is taking shape across industries and geographies. Engineers at top solar panel companies are hard at work developing innovations making solar even more...
5 Reasons to Consider a Career in the Solar Industry
Solar energy, unfortunately, is still viewed as an alternate power source. However, in spite of this designation, it is quickly becoming the primary source of...
Amazon Has Finally Decided To Become A Leader in Renewable Energy
Back in 2015, Greenpeace did a sophisticated research project on the sustainability of the top tech giants in the United States. It covered many areas of sustainability,...
Most solar installation companies provide financial projections to homeowners estimating what their savings will be twenty or twenty-five years after the time of installation. But...
It’s International Women’s Day! Today we recognize and celebrate women all around the world. As a member of Solar.com’s female population, it’s necessary for me...
A Review of LG Solar Panels - When Brand Name Does Matter
LG is a brand you may already be familiar with. They are a South Korean multinational manufacturer that makes televisions, mobile devices, tablets, smartwatches and...
This paper highlights the importance of power tolerance when choosing solar panels. Power tolerance is a measure of how much electrical power a solar panel...
Gauging the Bankability of Small to Mid-Sized Solar Installers
The entire world is going green and moving toward cleaner sources of energy. California hosts a flourishing solar industry with a burgeoning number of solar...
At Solar.com, we believe in supplying quality equipment for our customers. In the last twenty years, solar technology has grown exponentially, costs have plummeted,...
Elon Musk's Gigafactory Should Be Dictating Your Solar Equipment
All solar installations today should be thinking ahead to the not-so-distant future. The main question to be asking is whether your solar system will seamlessly...
We all know why people go solar: investment purposes, immediate savings, environmental concerns, and grid independence. But who are these people? One of Malcom Gladwell’s...
The following letter is from a very reputable company in Solar.com’s installer network to a homeowner who was unfortunately taken advantage of by an installer...
Bankability: What it Means and Why it is Important for Your Solar...
Homeowners who are considering solar typically overlook the manufacturer of their solar panels, despite this being one of the most important factors for the longevity...
The U.S. Department of Energy invests in new technology to revolutionize the landscape of solar data. Reliable solar grid data, the true performance of solar...