Wall-mount charger cracked my garage drywall — should I have used a stud finder or is this a design flaw?
Installed a 40A wall-mount charger myself this spring in the garage, used heavy-duty drywall anchors rated well above the unit's weight since there wasn't a stud lined up where I needed the mounting height. Four months in and there's visible cracking in the drywall radiating out from two of the four anchor points, and the whole unit now shifts something like half an inch side to side every time I plug in or unplug — you can watch it move if you're looking at it. My wife is, understandably, not thrilled about a chunk of the garage wall looking like this four months after I told her I had it handled.
I've got an EE background so I trust my read on the electrical side of this install, but I'm second-guessing the mechanical mounting entirely. Was this always headed here with a heavy wall unit on anchors instead of a stud, or is a 40A charger just inherently going to do this to drywall regardless of what it's screwed into? Trying to figure out if I need to actually find a stud and redo this properly, or if a lighter unit at the wall side would've sidestepped the whole problem.
Filed under: Outlet & Electrical Safety
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9 answers
9 ANSWERS
@gravelfox88July 24, 2026
Anchors rated for the static weight of the unit only account for straight-down pull. Every time you plug or unplug, you're adding a lateral/torque load on top of that, and drywall anchors just don't have the shear strength to handle repeated lateral loading over months, no matter how high their rated pull-out number is. A 40A unit really needs to land on a stud or a mounting plate that spans two studs.
If I go back in and mount a plate that spans two studs instead of trying to hit a single stud dead center, does that solve it even with the unit staying just as heavy, or am I just deferring the same problem to a bigger footprint?
That solves it. Spanning two studs distributes the load across two solid anchor points instead of concentrating it on drywall between studs, and it eliminates the racking movement entirely because the plate itself doesn't flex. Weight isn't the enemy as long as it's transferred into framing instead of into the wall board itself.
@kmoore79July 24, 2026
Seen the same thing on a few installs where the guy wasn't a stud away from center and just went with anchors instead of moving the box a few inches. Once the drywall cracks around one anchor point, the load redistributes to the remaining three unevenly, which speeds up cracking at those too. It snowballs once it starts.
@quietwalrusJuly 24, 2026
I'd put less emphasis on the static weight itself and more on that half-inch of movement every time you plug or unplug — that's the real killer here, not the resting weight. A 40 lb unit sitting perfectly still on anchors can actually hold up fine for years. It's the repeated racking motion from insertion and removal that walks the anchors loose and cracks the board around them.
is the half inch of movement actually dangerous or just annoying to look at? mine wiggles a little too and now i'm worried
@duskravenJuly 24, 2026
Went through basically this exact fix on mine, moved the box six inches over to land a mounting plate across two studs instead of fighting with anchors. Took an extra hour of work and solved it completely. Wish I'd just done it that way the first time.
Is there an actual mounting-plate product for spanning two studs like this, or just a cut piece of plywood people diy?
@tinycabinetJuly 28, 2026
My wife would not be happy either.
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