charred rivian r1s offers warning about charging with extension cordsCharging an EV at home is supposed to be about as thrilling as plugging in a phone. One Rivian R1S owner got the opposite experience, and the photos are brutal.charred rivian r1s offers warning about charging with extension cordsImages posted to the Rivian subreddit show an R1S whose entire front end is cooked, plus substantial fire damage to the garage next to it. The Reddit user who shared the pictures said they came across the aftermath while walking the dog, and a neighbor said the blaze broke out while the Rivian charged through an extension cord.That is a secondhand account, and worth treating as one. There's no fire department report confirming the cause, so the extension cord claim can't be verified, nor is it known which cord, outlet, or charging setup was involved. One commenter argued the photos look like a NEMA 14-50 RV-style extension cord instead of a cheap household cable, though that too is just a reader's read of the pictures.The important part: the Reddit poster says neighbors confirmed the SUV's owners were okay.Whatever the exact cause, Rivian's position on extension cords is not ambiguous. In its owner's guide, the automaker tells drivers not to connect its Portable Charger to "an extension cord, power converter, power strip, or any type of power adapter." It also cautions against damaged, loose, or worn outlets.charred rivian r1s offers warning about charging with extension cordsThere's a reason for the caution. The brand's J1772 portable charger can draw as much as 32 amps and deliver 7.6 kW on a 240-volt outlet. It won't draw those maximums constantly, but it's moving significant current through the cordage for hours at a time, which is exactly the scenario where undersized wiring, a damaged connection, a coiled cord, or an overheated plug turns into a problem.The Reddit thread sparked the predictable debate, with some arguing a properly rated heavy-duty cord can handle the load. Maybe so. But Rivian's wording leaves no wiggle room. It says don't use one. In this case, following that advice might have kept the R1S intact.[Images: Rivian]Become a TTAC insider. Get the latest news, features, TTAC takes, and everything else that gets to the truth about cars first by subscribing to our newsletter.