Transfer Switch Heat Related Failures

On November 5, 2015, the Office of Defects Investigation (ODI) sent an email to IOTA Engineering LLC (IOTA) requesting certain information about the automatic transfer switches recalled by several recreation vehicle (RV) manufacturers. IOTA responded with emails dated November 13, 2015 and May 23, 2016. In their response, IOTA stated that it sold 15,330 automatic transfer switches to 42 RV manufacturers who, along with IOTA, have not submitted defect information reports to the agency in accordance with 49 CFR 573.6. ODI contacted 2 of these 42 RV manufacturers about the subject components and they both report that no safety defect trend has been identified. Furthermore, IOTA states that it has made a determination that the subject components themselves are not defective and when installed correctly in its intended application the switch performs reliably and without incident. More than one RV manufacturer who did conduct a safety recall acknowledges that sporadic installation error was likely responsible for at least some thermal events experienced on their vehicles. Once the alleged defect trend became apparent, several RV manufacturers paid special attention to installation processes, yet thermal events continued to occur on their vehicles. Furthermore, some RV manufacturers allege that re-torqueing of the terminal screws did not remedy the alleged defect and there may possibly be other as-of-yet unidentified reasons why properly torqued terminal screws may loosen over time resulting in a high resistance connection. While no RV manufacturer has identified a single specific root cause for thermal events involving the subject component, the frequency of thermal events reportedly diminished significantly once they changed transfer switch suppliers. To date, ODI is aware of 31 complaints related to thermal damage of automatic transfer switches manufactured by IOTA. However, all 31 complaints are related to the performance of existing safety recalls, such as scope or o