Plug-In Solar: Know Before You Buy
Simple idea but there are important considerations
Manager’s Article
Small plug-in solar systems are attracting growing attention in parts of the country. Sometimes called balcony solar, portable solar, or plug-and-play solar, these systems typically include one or more panels and a small inverter. They are marketed as an affordable do-it-yourself option that can be placed on a balcony, patio, deck, or in a yard and connected to a standard wall outlet.
The appeal is understandable. Plug-in systems generally cost less than a traditional rooftop solar installation, can be easier to set up, and may be attractive to renters or homeowners who do not want to make a permanent change to their property. When the sun is shining, the panels produce electricity that may offset a portion of the electricity being used in the home. For members interested in renewable energy, these products can appear to offer a simple way to get started.
However, plug and play does not necessarily mean “plug in anywhere.” These systems differ from portable solar panels used only to charge a battery or power equipment directly. A system connected to a household outlet can send electricity into the home’s wiring and potentially back onto the electric system. That raises important questions about the condition and capacity of the home’s wiring, electrical-code compliance, equipment certification, required permits and utility interconnection requirements.
A household branch circuit is ordinarily designed to receive power from the electrical panel in one direction. Adding another source of electricity through an outlet may allow the wiring to carry more current than it was designed to handle without the circuit breaker detecting the full load. Improper equipment or installation could result in overheated wiring, fire or electric shock. Outdoor connections also require special attention because moisture, damaged cords and incompatible ground-fault protection can increase risk.
Members should also understand that solar panels continue producing electricity whenever sufficient sunlight is present. Simply unplugging a system does not necessarily mean every component is de-energized. In addition, a system that does not shut down properly during an outage could send electricity back onto a powerline, creating a serious hazard for line workers and others who may reasonably believe the line is no longer energized.
Cost and savings should be considered carefully as well. Actual production depends on panel size, orientation, shade, season, weather and local conditions. A system costing several hundred dollars or more may produce only modest daily savings. Before purchasing, compare the total installed cost, including mounting hardware, electrical work, permits and any required equipment, with a realistic estimate of annual energy production. Be cautious of advertising that promises large savings without accounting for Montana’s seasonal conditions, our lower-than-average retail energy rates, or your home’s actual energy use.
Product standards and rules for plug-in solar are still developing, and requirements may vary by location. Before buying or connecting a system, members should contact MEC, consult a qualified electrician, verify that the product is listed and labeled by a recognized testing laboratory for its intended use, and check applicable permitting and inspection requirements. Never use an extension cord, power strip, adapter or improvised connection unless expressly permitted by the manufacturer and applicable electrical codes.
MEC supports members who want to better understand their energy choices. Our goal is not to discourage new technology, but to help ensure it is used safely, legally and with realistic expectations. If you are considering plug-in solar — or have already purchased a system — please call our office before connecting it. We will be glad to answer questions and help you understand the requirements that may apply in a safe and informed way for everyone involved.
