HPWC on Hardiplank?

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#1
Hi folks. I've recently ordered a Model 3, and the HPWC. The forums have been helpful to me already, though I've only now signed up.

I want to mount the HPWC to the exterior siding on my home (under an overhang, outside, which I understand should be fine). My question is about mounting to hardiplank. Can I mount to hardiplank directly, or does it need to go into a stud? I'm not sure how heavy the HPWC is (hasn't arrived yet). If it has to go into a stud, any tips on finding a stud through hardiplank? :)
 

MelindaV

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#2
using (4) screws long enough to go into the sheathing under the hardie. so something like 2" wood screws to go thru the ⅛" bracket, ¾"-1" lap siding and the ½"-⅝" sheathing, you would be fine. (you will need to pre-drill the hardie, and before you add the screws, shoot some sealant into the holes as you will likely be screwing thru a weather barrier too)


(its just WC, the 'HP' was dropped with the daisychainable version they started selling in 2016)
 
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#3
I don't know what hardiplank is, but the HPWC isn't particularly heavy. I'd feel OK mounting it on drywall with the appropriate Molly bolts, so as long as hardiplank is at least as tough, you should be fine.
 

GDN

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#4
You should be fine just mounting to hardiplank. I'd think a concrete screw possibly for durability. Studs are likely 16 inch on center, older house possibly 24 inch on center. If you have an existing electrical plug on that wall, that would give you something to measure from as they are attached to a stud. If you have a really good stud finder, it might register through the hardi. Be wary of other electricity or water pipes that might be in the wall.

Can you see the top row of hardi? Does it have a trim piece that you might be able to see the nail/screw holding it up? If so you can measure from there possibly too.
 
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#5
Thanks for all the comments. I wasn't even considering that there's sheathing behind the hardiplank... gives me some confidence that it'll be just fine. Thanks!
 
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13004

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#6
I have Hardie on my Nothern house. I would definetly find a stud to attach the HPWC/WC bracket to. If you have access to the inside wall of where you are mounting your EVSE, finding a stud should be no problem. I would suggest galv or stainless lags into the stud. Like MV suggested, pre-drill the Hardie. I mounted one of my HPWCs inside my garage and deployed a nailer to attach said HPWC. I would do the same if I was mounting the HPWC outside on my Hardie if the stud was not in the preferred location.

Good-luck!
 

samson

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#7
I have also order the HPWC after Model 3 delivery confirmation.

Is there any guide on what materials I need to give to local electrician if I would like to have HPWC as plug in to NEMA 14-50 and not hardwired, I am aware of the 40A max output by this method.

Thanks
 
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13004

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#8
No guide that I am aware of other than the instruction manual. You are correct with the 40a (continuous) output that must be appropriately sized on a 50 circuit. I am sure your “electromagician” will know to run at least 6 ga. Romex or 8 ga. wire in conduit (THHN, THWN) depending on length of run. But why waste $ and copper deploying a NEMA 14-50 receptacle when a NEMA 6-50 can be installed since there isn’t an EV on the planet that uses a neutral for 240v charging? Since so few of us now require (except the campers on this forum) campground charging on a regular basis anymore like we did 5+ years ago with the availability of superchargers and destination charging, I am very surprised that Tesla hasn’t made the 6-50 the default adapter and wiring device of choice. There isn’t a provision for a neutral to be wired into a WC or HPWC and the neutral prong on both Gen I UMC and Gen 2 MC 14-50s is dead and has no connectivity. You may need to 'edumacate' your electrician on the proper dip settings. Jus my $.02.

Good-luck!
 
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13004

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#9
Ok, I just removed one my HPWCs at 3am last night. I used 4ga. and set the dips to max out at 72a with a 90A 2-pole breaker. I had forgotten how much effort/pulling is required when using wire of this size. I do not force things when I work on equipment and I am not a “bolt breaker” (we all have friends that are:eek:), but there is no way that my Hardie would securely locate my HPWC . I used (2) 2 1/4 “ long 5/16” galv lag bolts to secure the HPWC aluminum mounting backing plate to my nailers. For fun, I counter sunk the inside area around the wire feed-thru hole so that my Romex style connector nut would sit flush on the inside mounting surface to gain addition room for making the very tight radius bend into the connection ports. I think Tesla improved the design on the later WCs to gain additional wire clearance into the termination ports.