Tesla is giving new and existing owners of its electric S Model a new wall plug for recharging, along with the latest on-board car software if they don't already have it. The company says the move is to fight "higher than normal electrical resistance" that could make the charging adapters warmer than usual. The newer plug has a fuse that will stop charging if that begins to happen, something that halts overheating.

A preemptive measure

"Even if the circuit breakers on the house side and car side don't trip, the thermal fuse will prevent current from flowing if the wall socket region heats up for any reason," Tesla said in a statement announcing the new adapters. "Although we do not believe the improved adapter is required to address the issue, we are taking this step as part of our commitment to full customer satisfaction."

The software went out as a free update last month, and changed how charging works on the electric vehicle. If fluctuations in current are detected, the on-board system reduces current by 25 percent in an effort to curb any potential issues with a bad charging station. Tesla says both the update and the newer plug design increase safety, but that the risk of running into the power issues is "unlikely."

The changes come just two months after Tesla asked the US National Highway Transportation Safety Administration to investigate the a separate issue affecting the undercarriage of its Model S cars. Road debris can fly up and hit that area, which shields the car's battery, something that is believed to have led to two fires. The NHTSA is still investigating that issue.