Just finished fixing my balcony door setup — a few observations

I went through the exact same struggle last summer with my Bluetti setup. I was pinching a thick orange extension cord through the sliding glass door frame, and not only was it a safety hazard, but it also let all the cold air out of the apartment. I finally bit the bullet and had a TayMac "In-Use" cover installed. Having that extra deep housing is huge because it allows the door of the outlet box to stay shut even when the heavy power brick is plugged in.

One thing I did differently was asking the guy to run the wire through a bit of liquid-tight conduit along the railing. Since my balcony gets direct southern exposure, even the "outdoor rated" cables started to get brittle and yellow after just one season. The extra $40 for the shielding made a massive difference in how the setup handles the heat. It’s such a relief to actually hear the door click shut properly now. Before the dedicated socket, I’d wake up at 3 AM during thunderstorms just to make sure the connection hadn't vibrated out into a puddle. Now, I just leave the battery out there under a small ventilated riser and don't think twice about the weather forecast.

I actualy took a slightly diffrent route because my condo board is incredibly strict about drilling through the exterior brick. Instead of a standard wall mount, I ended up using a through-door power kit designed for thick frames. It’s basially a flat ribbon cable that adheres to the jam, but even that felt like a temporary fix once I started charging my EcoFlow Delta Max regularly. The heat buildup on those thin ribbon cables is no joke during a 1000W fast charge.

I eventually convinced them to let me run a 1/2-inch EMT conduit from the interior outlet out through the header of the sliding door frame. My electrician used a LB fitting to keep everything tight against the wall. The big thing he emphasized that I haven't seen mentioned is the height of the box. We mounted mine about 18 inches up to clear the splashing from the balcony floor during heavy storms. If you're in an area with heavy snow or pooling water, having it down near the baseboard is just asking for the GFCI to trip every time it gets slushy.

Also, make sure you use a high-quality silicone sealant like Lexel around the penetration point. Standard cheap caulk tends to shrink and pull away from the metal after one season of UV exposure, wich is how you end up with ants or a draft right near your feet.

That sounds like an improvement, but have you ruled out the potential for water ingress thru the new mounting holes? Even with a drip loop, if the pro didn't use a high-grade silicone sealant behind that mounting plate, you might just be trading a cord hazard for a slow rot issue inside the door jam.

Also, have you checked the door's latch alignment now that the frame isn't being stressed by that extension cord? Sometimes after months of being forced shut on a cable, the strike plate can get slightly out of whack. If it’s not seating perfectly, you’re still losing your climate control through the gap anyway.

Crushing a cable trough a Pella 350 Series or even a basic Milgard slider is the fastest way to kill the U-factor and invite a permanent draft. If you haven't alredy, check your bottom sweep for any compressed flat spots where that Jackery cable used to sit. usally, a quick swap to a Q-Lon foam seal fixes the air leak for good. I’m surprised you didn't just go with an Intermatic WP1010HMC for the outlet—those heavy-duty metal covers are bulletproof compared to the plastic ones and acutally stay shut when the wind picks up.

Quick update — I took your advice and checked the bottom sweep of my slider. It was definitly crushed from months of pinching that cable! I just swapped it for a new Q-Lon seal and the draft is finally gone. My electrician confirmed he used plenty of silicone behind the mounting plate too, so I’m feeling much better about the rain. everthing is finally sealed up tight!