How it works
In short
Plug-in solar produces electricity on your balcony, patio or yard, the same kind your utility delivers, and feeds it into your home’s wiring through a standard outlet. Load Guard measures your home and makes sure that power is used safely. Here is what each part does, why Load Guard is required, and how your home uses solar first to lower your power bill.
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Turn sunlight into direct current (DC) electricity.
Each panel is made of solar cells. When light hits a cell, it frees electrons in the silicon and creates a direct current. How much power a panel makes depends on how strong the sunlight is, the angle of the panel, shading and temperature.
Convert the panels’ DC into the 120 V AC power your home uses.
The AC matches the grid exactly, so it flows into your wiring together with utility power. Each inverter also tracks its panel’s best operating point all day.
Feeds the solar power into your home’s wiring.
Weatherproof DC cables connect each panel to its inverter. An AC cable connects the inverters to a standard household outlet. All cables and connectors are rated for outdoor use and for the current they carry.
Measures your home’s electricity use and controls the solar system to match it.
0.1 smeasures and talks to the inverters every tenth of a second
Load Guard sits in your breaker box. Its current sensors measure how much electricity your home is using and how much is flowing on the circuits your solar system uses, about every 0.1 seconds. It sends that information directly to the inverters, which adjust their output. Load Guard is what keeps your circuits within their limits and keeps solar power at home.
Use your solar power first, before anything comes from the grid.
Stores the solar power your home can’t use right away and gives it back later.
Load Shifter uses lithium iron phosphate (LiFePO4) cells without cobalt and plugs into a standard outlet. When Load Guard sees that your panels are making more than your home is using, the battery charges with the surplus instead of the system turning output down. In the evening, it gives that energy back to your home.
Also in every system
Holds your panels at the right angle, safely.
The angle and direction of your panels matter as much as their size. Kits from 800 W to 2,000 W come with aluminum ground-mount stands. 4,000 W kits come with a choice of the same stands or tub mounts.
Shows what your system is doing.
The free CraftStrom app shows your solar production, your home's electricity use as measured by Load Guard, and the status of every device. It is also where you set up and update your system.
Plug-in solar from CraftStrom, explained.
A short, high-level look at how a CraftStrom plug-in solar kit comes together: panels on their stands, smart inverters, Load Guard and the app, all connected to your home through a standard outlet.
Only at CraftStrom
CraftStrom Load Guard is the smart control device included with your CraftStrom system. It measures how much electricity your home is using and helps the system adjust solar output to match. That gives you more control than a basic panel-and-inverter bundle that produces at a fixed level whenever the sun is out.
Why it matters
Plug-in solar is safe when two things are guaranteed: the system must never overload the circuit it is plugged into, and it must not push power onto the grid without the utility's agreement. U.S. plug-in solar laws, the UL 3700 safety outline and the National Electrical Code all come back to these two requirements. In a CraftStrom system, Load Guard is the component that meets them.
New state laws set a size limit for systems that send power to the grid, for example 1,200 W, and require that a system does not overload the circuit it uses. Larger systems are allowed when they don't export: that is zero-export control.
UL 3700 evaluates the complete plug-in system. It includes requirements for power control, so a system that manages its own output keeps the branch circuit within its rating, together with protection against unintended export.
The NEC limits how much power may be fed into a circuit and an electrical panel (Article 705.12) and allows power control systems to enforce that limit automatically (Article 705.13). Load Guard's circuit-aware control works on exactly this principle.
Load Guard job 1
The wires in your walls can only carry so much electricity before they get too hot. Here is how Load Guard helps keep them safe.
Your breaker only counts the electricity coming from the power company. Plug-in solar adds its own electricity in the middle of the wire, behind the breaker's back, so the wire can end up carrying more than the breaker thinks. This is called breaker masking. We then throttle output to protect your wires.
Load Guard job 2
Your home uses solar power first. When your panels make less than your home is using, the grid supplies the difference. When your panels make more than your home needs, Load Guard turns solar output down. If you add a compatible battery, the system can store that energy for later instead. This is called zero-export control: the system is configured so excess solar power is not sent back through the utility meter.
One CraftStrom solar system is connected on one electrical phase. Load Guard measures electricity use on that phase and adjusts the solar system's output to match it.
CraftStrom solar systems are connected on both phases of a typical U.S. home. Load Guard controls each phase separately. Each solar system responds to electricity use on the phase where it is connected.
Load Guard can support protection logic for up to four separate plug-in system circuits. Each circuit is measured separately, which helps the system manage the output of the products connected to it, for example:
Your home uses solar power first. Solar power that is not used is lost. If your panels are making more than you are using, the system turns solar output down. With compatible battery storage, that energy is stored for later use instead, based on your system settings and equipment.
This keeps the system focused on the energy your household can actually use, instead of treating solar as a fixed output. It is also why knowing your own usage matters so much for your savings.
Solar first
Electricity always flows to where it is being used, along the shortest path. When your solar system feeds power into an outlet, your appliances use that power first. Your utility meter only counts the electricity your home still needs on top of it. With a battery, the order looks like this:
Whenever the sun is shining, your home runs on your own solar power first. Every kilowatt-hour from your panels is one you don't buy.
With Load Shifter, the solar your home couldn't use at midday powers your home in the evening.
Only what solar and battery can't cover is bought from your utility, as before. You never lose your grid connection.
12:00 am
Night: your home runs on the grid, as before.
Over the whole day, this home gets 57% of its electricity from its own solar: 4.0 kWh straight from the panels and 4.0 kWh from the battery in the evening. The other 6.0 kWh, mostly at night, comes from the grid as before.
Illustration of a typical home with a plug-in solar system and a battery. Your curves depend on your home, your system and the weather.
Plug-in solar saves money by replacing electricity you would otherwise buy. Each kilowatt-hour your home uses from your panels is a kilowatt-hour your utility doesn't bill you for, at your full retail rate, including the delivery charges that make up a large part of most bills. Because a CraftStrom system runs zero-export, solar power that your home doesn't use is not credited to you. That makes one number decisive: how much of your solar power your home actually uses.
| Solar energy your home uses in a year | 1,800 kWh |
| Your electricity rate | $0.30 per kWh |
| Electricity you no longer buy | $540 per year |
Illustrative example. Your production depends on location, orientation and shading; your rate depends on your utility. Estimate your own savings with our calculator →
Know your usage
Most people only see their electricity use once a month, as one number on a bill. Load Guard measures your home's use continuously, and the CraftStrom app shows it to you. That information is crucial to your savings: solar only saves money when it is used, and you can only line up your production with your usage when you know when and how your home uses electricity.
Your base load is what your home always uses: refrigerator, freezer, router, fans, devices on standby. Solar that covers your base load is used almost completely, so it is the most valuable part of your system.
A system that is much larger than your daytime use spends sunny hours turned down. Knowing your usage curve helps you choose a kit, and later an expansion, where nearly every kilowatt-hour is used, so you don't pay for panels you can't use.
Dishwasher, laundry, dryer, pool pump, EV charging: many loads can run at midday instead of the evening. Moving them into sunny hours turns surplus solar into savings.
Your data shows how much surplus your panels make at midday and how much you use in the evening. That tells you whether a battery pays off for you, and how big it should be.
Many utilities charge more in the late afternoon and evening. Knowing when you use power lets you shift usage and battery energy into those expensive hours.
A high base load at night often means devices that run without being needed: old freezers, heaters, standby electronics. Seeing it is the first step to switching it off.
A home uses about 350 W during the day while nobody is home, and a 1,200 W system produces up to about 1,000 W at noon. Without changes, a large part of the midday solar is turned down. Running the dishwasher (about 1.2 kWh) and one laundry load (about 1 kWh) at midday instead of the evening uses that surplus.
| Energy shifted into sunny hours | about 2.2 kWh per day |
| At $0.30 per kWh | about $0.66 per day |
| Extra savings, same system | about $240 per year |
Illustrative example. Actual savings depend on your appliances, your rate, the season and the weather.
Find the right system for your space, or talk to our U.S.-based team.
FAQ
Most homes use a standard outdoor or indoor outlet on a circuit without heavy loads. Load Guard watches your home's use and turns output down to stay within the safe circuit limit. Run our 5-point outlet check before you buy.
Tell us your bill and we'll show three numbers: conservative, typical and best-case. Savings come from using the power at home during the day.
Anywhere with 4+ hours of direct sun near an outlet: balcony, fence, deck, porch, shed or yard. The kit finder asks about your spot and cable run.
Solar alone lowers your bill but doesn't power your home when the grid is down. Add a battery kit to keep essentials like the fridge, lights and Wi-Fi running.
Yes. CraftStrom works in all 50 states. Load Guard keeps every watt in your home, so nothing flows back to the grid.
Your home uses solar first. If you're making more than you use, Load Guard turns the panels down, or a battery stores it for later.
See your full price, shipping and delivery window before checkout. No surprise accessories.
Yes. It unplugs and moves with you, and it works in all 50 states.
UL-certified inverters, NEC compliant, tested by Lawrence Berkeley National Lab and NREL, with warranties of up to 20 years.
Our Houston team can walk you through Load Guard setup or Wi-Fi by appointment, and our FAQ covers the rest. Call (832) 850-3832.
More questions? Call (832) 850-3832 or email us.
