By Patrick Thomas
Walmart Inc. is suing Tesla Inc., alleging that some of the company's solar panels sparked roof fires at several of the retailer's locations, adding to the problems the electric-car maker has had with its venture to power homes and stores.
In a suit filed in New York state court on Tuesday, Walmart said that as of last November, Tesla's solar panels were responsible for at least seven fires. The retailer is demanding Tesla remove the roof-mounted panels from more than 240 Walmart locations and cover the costs.
Walmart, the world's largest retailer, alleges the fires destroyed significant amounts of store merchandise and that buildings required substantial repairs, costing hundreds of thousands of dollars.
Tesla didn't immediately respond to a request for comment.
Some of the problems with the panels stemmed from a "rushed" approach to the system's installation, Walmart said in its filing, and that individuals sent by Tesla to inspect the panels lacked basic solar training and knowledge.
"Walmart's inspectors observed negligent and dangerous wire connection practices, which were readily apparent at many of the sites visited and are a critical risk factor in contributing to fires," the retailer alleges in its suit.
Walmart said it began using solar panels made by SolarCity, which Tesla acquired in 2016, in 2010.
Walmart had no comment beyond the suit. Tesla didn't immediately respond to request for comment. Shares of Tesla were off about 1.4% during aftermarket trading.
After acquiring SolarCity, Tesla began selling and leasing solar panels in Tesla showrooms, with the leases extending 10 to 20 years.
Later, Tesla began promoting sales as opposed to leases. Once the top U.S. residential solar installer, Tesla ranked No. 3 in the first quarter, with a 6.3% share, according to Wood Mackenzie, a firm that tracks renewable-energy projects.
The company this week said it was offering to rent solar panels to homeowners in Arizona, California, Connecticut, Massachusetts, New Jersey and New Mexico.
Last month, Tesla told analysts on an earnings call it was optimistic for its future in solar, saying its "energy products business will grow."
Write to Patrick Thomas at Patrick.Thomas@wsj.com