An arc-flash explosion, that occurred last year at an electric vehicle (EV) charging station in Hope, was caused by the station’s electricity system, says Technical Safety BC (TSBC).
In a report released on Oct. 22, TSBC said that the incident on Fort Street, which left a Tesla driver with minor injuries last year in August, was caused by the station’s battery-integrated FreeWire Boost Charger short circuiting.
In a video released by TSBC, the explosion took place when the driver tried to use a CCS1-to-NACS charger adaptor to connect the Tesla to the charging station. Within seconds a “short circuit in the battery module occurred in the charger” which caused voltage to be sent through the ground circuit. This resulted in a buildup of heat inside the adaptor and the arc-flash happened soon after.
In TSBC’s investigation it confirmed that the adapter was not safety-certified or approved for use in Canada. However, at the time of the incident, there had been no approved standard for adaptors in the country. This means it wouldn’t have been possible to test it.
TSBC also confirmed that, before the incident, the driver had used the adaptor around 50 times without any concerns or problems.
The driver only suffered scrapes and abrasions when he was knocked back by the explosion. However, the explosion left “burn marks on the vehicle, complete destruction of the CCS1-to-NACS charger adapter, damage to the charging cable, and damage to the charger’s internal components.”
The adaptor was manufactured by A2Z EV who did their own investigation and found no problems with it. The company also confirmed that “the damage observed was consistent with exposure to an external ground fault originating from the charging station.”
“It is our understanding that the charging-station operator has since conducted a review of its systems and made internal adjustments aimed at preventing similar occurrences,” A2Z said in a press release on Oct.18. “In a normal EV charging setup, no current should flow continuously through the ground conductor — it exists only as a safety path in case of a fault.
“In the Hope incident, the adapter simply became part of the fault path; it did not cause or sustain the current. Under safety standards, the charging station should have instantly detected and interrupted that fault.”