Thoughts on repair vs. total replacement for unpermitted service mess?

I've dealt with these "flipper specials" more times than I care to admit. In my experiance, once you see water tracking down the service entrance conductor or thru a hacked-in pipe right onto the main, the clock is ticking. I had a similar call last year on an old Square D Homeline where the water had acutally started to pit the busbar behind the breakers. Even if you scrub that off, the factory plating is gone, and you’re just waiting for a hot spot to develop. For me, the line is drawn at that water intrusion. If the main breaker has been getting dripped on, its internal trip mechanism coud be compromised or seized from rust. You can't realy test that reliably in the field. By the time you spend hours chasing those double taps and trying to patch a hole in the side of a rusted-out enclosure, you’re alredy halfway to the labor cost of a full swap. I usally tell the homeowner that I won't put my name on a patch job when the core integrity of the service is shot. It's better to pull a permit, install a fresh Eaton or Siemens pack, and know they won't have a fire next time there’s a heavy storm.

I've seen these "flipper specials" too, but I ussually try to get a Megger on those lines before condemning the whole can. If the water was just hitting the top of the main breaker and hadn't wicked into the busbar's plating, you might just be looking at a main breaker swap and a proper 2-inch hub installation. I’ve cleaned up plenty of older GE or Siemens load centers using a fine wire brush and some No-Ox-Id A-Special once the moisture source was sealed. The double and triple taps are just a housekeeping issue. As long as the bus isn't pitted or showing signs of arcing, you can clear those up in an hour with some pigtails or just moving them to those open lugs you mentioned. If the voltage drop is acutally coming from a loose neutral or a bad connection at the weatherhead rather than the panel itself, a full swap won't even fix the primary problem. I'd rather spend the client's money on a solid surge protector and a proper service mast than a new box they don't strictly need.

While others suggest a Megger test, I find that such assessments often neglect the latent capillary action that draws moisture into the stranded core of the feeders themselves, wich, when combined with a non-existent connector in a rusted enclosure, suggests a total systemic failure. Given that the factory dielectric grease has likely been emulsified by the moisture, resulting in accelerated galvanic corrosion at every mechanical connection point, I am firmly of the oppinion that attempting to mitigate the double taps on a compromised busbar is an exercise in futility. Is there any evidence of zinc chromate depletion on the interior chassis, or has the oxidation allready transitioned into deep-seated pitting that whould render a new main breaker's contact surface effectively useless?

Don't waste a second trying to salvage a rusted-out can. Once that water hits the main, you're looking at a ticking time bomb. I’ve seen those old QO or Federal Pacific panels where the corrosion works its way right into the breaker's internal spring assembly. You can't see it, but it's there. I’d rip it all out and throw in a 200-amp Square D QO Load Center with a proper Myers Hub to seal that top entry. It’s the only way to sleep at night. While you're at it, check the meter socket; if water's in the panel, it usally started at the service head or the meter lugs.

Update: I went with a full panel swap. That point about latent capillary action in the feeders was the clincher—once I stripped them back, the copper was allready turning black deep inside the insulation. It definitely wasn't worth trying to salvage a 'ticking time bomb.' New service is in, properly grounded, and the homeowners are finally sleeping better.