Tesla Updates Software Against Potential House Wiring Deficiencies

By now everyone knows that if you publish the words “fire” and “electric car” in the same headline, it is sure to get clicks.

We carefully avoided that cheap trick here, but with that truism as background, Tesla has issued a software update to potentially prevent fires from Model S owners who manage to plug into under-capacity or faulty electrical circuits.

Model S owners were not explicitly told whether last week’s software update v5.8.4 was in direct response to a Southern California garage fire in November, but Tesla spokesperson Liz Jarvis-Shean told us today the fix was already in the works, and not a reaction to the fire that did create some unwanted publicity for Tesla.

Tesla’s action can at least be considered preemptive, and an improvement to safety when drivers are still learning the do’s and don’ts of proper car charging.

One way to recharge is the popular use of an optional Tesla NEMA 14-30 or NEMA 10-30 adaptor that can plug into a clothes dryer line to route the power to the car’s electric vehicle service equipment. This is not necessarily a problem assuming the line can handle it, but does leave open the possibility to casually plug into power lines that may not be up to the task.

Beyond that, any number of building wire connection faults can be a culprit leading to overheating and fire.

The Model S can draw electrical current at a high amperage rate, and even at normal EV charging levels, improper, old, or defective wiring connections in a building’s wall can overheat with results that no one wants.

Tesla’s update, v5.8.4 offers an explanation to Model S owners as follows:


As noted, Tesla’s move followed a garage fire involving a Model S at the UC Irvine Nov. 15 which has spun a few stories saying “Tesla fights back hard” against an exclusive Reuters report on the same.

The Reuters story opened with the following sentence:

A fire department in Southern California said a garage fire may have been caused by an overheated charging system in a Tesla Model S sedan, in the latest link between the top selling electric car and the potential for fire.


And, it was quickly called “misleading” by Tesla’s Jarvis-Shean who cited company records on the car in question showing nothing had been improper.

“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,” the company said. “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.

According to the fire department’s report which Reuters obtained, the document concluded as follows:

Based on my knowledge, experience, fire patterns observed, witness statements, and examination of the overall fire scene, it is my opinion the cause of this fire is accidental. 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 plugged into the 240v wall socket. The vehicle started charging at midnight and was still in the process of charging when the fire started. The plug was still inserted into the vehicle and the LED light was blue. The fire spread to the cardboard boxes stored on the metal shelving unit and the pressboard wall covering. Due to the amount of damage from the fire, I was unable to determine if the heating occurred inside the junction box or at the Universal Mobile Connector.

The heat source was generated from a high resistance connection, the item first ignited was the plastic wire insulation and cardboard, and the event that brought the two together was the charging of the electric vehicle. This case is considered closed unless further information.


Because Tesla did not state clearly whether or not update v5.8.4 was a direct result of the PR fire it had to put out, it did leave owners speculating in its online forum.

In general, owners are assuming the one event was in response to the other.

For being perceptibly fast on its feet, Tesla is being praised by some Tesla fans who say it showed swift decisive measures that were lightyears quicker than say, General Motors might have been to proactively handle a potential weak point.

Tesla’s software update comes just in time for the holidays when people will be visiting, and the last thing Tesla needs is for someone to ask Grandma to use her dryer line to recharge their car, and inadvertently have her house ignite as a result.

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