My bulkhead connector fried in the '80s. My amp gauge was bypassed a few years ago after I noticed it was almost always 3 lines toward the charge side, after I added a stereo, amp, halogen headlights, fuel injection computer, hi-amp alternator, etc.
In the article, they are talking about all of the current that goes through the AMP gauge. Basically ALL of it, in the stock-wiring configuration. If one of the terminals "SHORTS" against the "through the cluster hole" arcing could start that could end with the wiring, carpet, interior, whole car, burning to the ground. One guy’s car was saved because he acted quickly and always kept his ground battery post loose and pulled it.
(I never leave a clamp loose, If it ever comes loose on it's own, you lose your reference voltage and lose everything electrical in the car except the alternator. I found this out the hard way. I keep a 1/2 wrench in the console but how fast can you disconnect your battery if the interior is on fire? Never tested that.)
Rob