Tesla is recalling more than 29,000 charging adapters for its Model S line because of a potential fire hazard, the electric auto company said in a letter to the National Highway Traffic Safety Administration over the weekend.
“When charging, higher than normal electrical resistance connections to external energy sources may cause excessive heating of the adapter,” the company said. “Electrical resistance heating in the adapter or at the interface to the wall socket may lead to melting of the adapter, cord or wall receptacle, and possible electrical arcing that could lead to fire.”
The company said that “corrosion, physical damage to receptacles or inappropriate wiring/installation can cause higher than normal resistance” when using the NEMA 14-50 adapters to charge the vehicles.
Tesla has already pushed a software upgrade that “fully addresses the issue,” by reducing the charging current by 25 percent when it detects unexpected fluctuations in power and higher resistance connections. But the company decided the recall was “appropriate as a precautionary measure,” it stated in the letter.
Late last year, there were several reports of Tesla cars catching on fire after running over road debris, and a Nov. 15 event in Irvine, Calif., in which a garage was set aflame. Following those events, the company launched reviews of its designs and the incidents themselves.
But despite those reports and the recall today, a spokesman said in an email that Tesla “isn’t aware of any fires that have been definitively caused by its cable.”
Rather, the company seems primarily to blame errors on the part of whomever installed the wall receptacles that allow the cars to be charged. The company doesn’t do these installations itself. They’re often outsourced to an electrician or other third party.
“Initial analysis demonstrated that defective or improperly installed wall receptacles that the NEMA 14-50 adapter plugged into could cause problems including melted adapters and, in a worst case scenario, fire,” the company said in the letter.
Chief Executive Elon Musk echoed this point in an interview with Bloomberg: “These are very rare events, but occasionally the wiring isn’t done right. We want people to have absolute comfort, so we’re going to be providing them with an upgraded adapter.”
Tesla acknowledged that a small percentage of its Universal Mobile Connectors, which the adapter in question plugs into, had been returned after they stopped working and showed signs of internal damage. But it said it didn’t see the returns as a safety matter because the damage was contained within the connector and cut off power flow when the damage occurred.
The company will mail the upgraded adapters to customers after production commences and stock becomes available, which is expected within the next two weeks.
“Tesla does not believe the improved adapters are required to address the issue, but is including this measure to ensure confidence in all Tesla-branded products,” it said.
The expense of the replacement adapters is not expected to have a material impact on earnings, the spokesman said.
This article originally appeared on Recode.net.