‘Tis the season for festive lights, family gatherings—and residential building fires. Usually wintertime home fires start because of factors like heating, cooking, and dry trees strung with lights close to fireplaces and candles, along with the simple fact that more of our activities take place indoors. But last month, the owner of a Tesla Model S electric sedan in Irvine, California awoke just before 3 a.m. to a fire in her garage, where the car was plugged into a 240-volt wall socket.

As the fourth report since October of a fire involving the best-selling electric car, the incident has garnered a tad more attention than your typical electrical fire. Citing a copy of a report by the local fire authority, Reuters has reported that investigators could not pin down the definitive cause of the fire. “The most probable cause of this fire is a high resistance connection at the wall socket or the Universal Mobile Connector from the Tesla charging system,” the report says, according to Reuters. Tesla, meanwhile, has conducted its own inspection of the car, its charging cable, and the vehicle’s data log, and concluded that the battery was charging normally. The company said in a statement, “Based on our inspection of the site, the car and the logs, we know that this was absolutely not the car, the battery or the charge electronics. There was a fire at the wall socket where the Model S was plugged in, but the car itself was not part of the fire. The cable was fine on the vehicle side; the damage was on the wall side.”

The most likely explanation, according to fire protection engineer Peter Sunderland, an associate professor at the University of Maryland, is poor wiring. “Imagine a wire barely touching onto a screw,” he said. That bad contact can create resistance heating. “Otherwise, if that’s done properly, two things need to be a problem: the car needs to be drawing too much current, and the circuit breaker in the house didn’t activate. Both those things can happen, but it’s unlikely both those things happen at the same time—it’s a two-point failure.” Sunderland, whose current work includes fire-testing lithium battery cells for Ford, also offered a third explanation. “It’s possible the electrical outlet was faulty, just made badly in the factory.”

Electrical fires make up a small portion of all home structure fires—only about 13 percent between 2007 and 2011, according to the National Fire Protection Association. But they exact a high toll, resulting in more deaths and higher dollar losses on average than other types of residential fires. Electrical issues leading to fire can include short circuits from worn or defective insulation, faulty contacts, broken conductors, and mechanical failures.

Especially in older homes, overloading circuits is a risk. Fires can result from “outdated wiring that is deteriorating, inappropriately amended, or insufficient for the electrical loads of a typical household in the 21st Century,” the U.S. Fire Administration warns. “If an outlet is added to an existing circuit, then the load easily can be more than the wiring originally was designed to conduct.”

Of course, 20th-century technologies present their own risks. “Gasoline is very flammable,” Sunderland said. “And that can catch fire in your garage, too.”

Comments

  1. Andrew
    UK
    January 11, 4:50 pm

    Philly Jimi – as has been pointed out in studies, with millions of electric vehicles on charge overnight night-time electricity supply will become the new peak demand. Most people are out during daytime but with millions of electric vehicles charging overnight homes will draw current all night, every night with figures only ever increasing.

    Secondly, re-chargeable batteries rely on noble metals like lithium and neodymium. Those are only sourced in a few areas of the world such as China and Bolivia who will control the world market as surely as the Gulf states currently do with oil. China has 95% of the world’s neodymium (used in generators such as wind turbines) and is starting to impose controls on supply. Most lithium comes from Asia, Russia and Bolivia – nations who control the world’s supplies of that element.

  2. Philly Jimi
    Philly
    January 8, 3:03 pm

    Counttrarian – As if interviewing a person who has an interest in e-cars failing and not becoming a dominate segment of the market is somehow going to me more fair?

    As what exactly are we comparing this to? It isn’t like car fires in traditional automobiles never happen. Actually they happen quite often. Maybe there is a problem with the cable and/or overloaded circut in the house? This isn’t a problem that can’t be overcome.

    Andrew – the efficiency a which a modern power plant can produce electricity from fossil fuels is much much better then an internal combustion engine. Otherwise you’re getting a better bang for the buck. If most of the charging occurs at night it would be better because demand is much lower at night.

  3. Smith
    USA
    January 2, 3:00 am

    Tesla has poorly designed charge connections that are known for over heating, causing fires and causing injuries. A firefighter was injured responding to the Tesla related garage fire. Allegedly a Tesla owner was burned on the hand and arm pulling off overheated and burning charge connector. Many of these poorly designed Tesla connections have overheated and failed. They are known for melting. Greedy people are covering up these problems.

    The way Tesla has designed its charge connectors, is likely to put undue stress and possibly cause wall outlets to fail. Their adapter acts as a lever to increase the force on an outlet, so someone pulling on the cord, the weight of the module, and anyone tripping or tugging on the cord, the force is multiplied. The typical configuration as many connections close together which concentrates the heat and increases the odds of a bad connection and increases the odds of a fire.

    The Tesla software update is just a Band-Aid. There still is an underlying issue of bad Tesla hardware/electrical connections. All electric automotive manufactures need to be more careful about engineering designs, manufacturing and addressing safety complaints/criticisms of batteries and charging systems. These problems need to be nipped in the bud now, before the potential safety hazards can multiply.

    http://www.teslamotorsclub.com/showthread.php/15304-Plug-Adapter-on-my-Universal-Mobile-Connector-has-melted

    http://www.teslamotorsclub.com/showthread.php/18092-Schmelted-UMC-NEMA-14-50

    http://www.teslamotorsclub.com/showthread.php/23212-Scary-issue-with-Nema-14-50-adapter-melting

    http://www.teslamotorsclub.com/showthread.php/25444-Melted-Charging-Adapter-Cord

    http://www.teslamotorsclub.com/showthread.php/15304-Plug-Adapter-on-my-Universal-Mobile-Connector-has-melted?p=316665&viewfull=1#post316665

    http://www.teslamotorsclub.com/showthread.php/15304-Plug-Adapter-on-my-Universal-Mobile-Connector-has-melted/page7

    http://insideevs.com/tesla-mode-s-garage-fire-official-incident-report/

  4. Andrew
    UK
    December 30, 2013, 11:30 am

    This highlights one of the major problems with electric vehicles. If there are millions of these vehicles around, as the green lobby advocate, just how are they all to be recharged? Millions of vehicles recharging overnight would cause such a load to the grid and the extra current would have to be generated by fossil fuels – being burned at a higher rate than now!

  5. Soccer-coach-27
    San Jose,CA
    December 20, 2013, 6:00 pm

    I guess the writer needed someone with a title to make them and “expert,”, but any experienced electrician could have told you the same thing.

  6. sam rai
    United States
    December 20, 2013, 5:16 pm

    Counttrarian,
    i completely agree!!! It reminds me of when ESPN interviews an NFL player about the NFL…..it’s so stupid!!! Couldn’t they get someone in NASCAR or something? I mean an NFL player is going to be so biased about the NFL…who wants to hear what they think?…especially when they have so much first hand knowledge about it????

  7. Counttrarian
    NYC
    December 20, 2013, 10:46 am

    “Sunderland, whose current work includes fire-testing lithium battery cells for Ford”

    You couldn’t find an expert without ties to lithium battery cells AND the automotive industry ?