Originally posted in 2018 to a boating list. It has become relevant again in discussing CW. I would prefer to not put this out there but recent conversations cause me to believe (again) that someone's going to ignorantly kill their or someone else's ass:
Reluctant to post this... I like my anonymity but I will offer I am "qualified" to comment on how electrons move in a conductor.. what ground/bonding ACTUALLY is... and how to diagnose/isolate nontrivial electrical problems which I will add I spent decades doing for others around the world by finding "the bad decider" (human) instead of pouring over the failed design. How that approach works in complicated and beyond the scope of what I wish to accomplish here. More than all that, the entire back half of my career was finding REALLY crappy technical decisions in high-consequence situations with what are very low and opaque/unknowable risk probabilities. So.. let me put something out there just once.
Tribal knowledge about lots of things is great. Tribal knowledge about mechanical and in particular electrical/electronic things is insanely poor... no... insanely wrong in the expected case. Since the beginning of 2017, I have had 9 people... not crack addicts... not pill heads.. people successful in life most who know me and what I did for decades LECTURE me on how electricity works and why I just had to be 180-degrees wrong about something which, in all 9 cases, they asked for my opinion. None had ANY actual training in anything electrical. None were practitioners of anything that involved electricity. Their 0 hours to my multiple 10's of thousands of hours. All were armed with "tribal knowledge" (e.g. forums and email lists). Nice guys... and also idiots... as most humans become post-financial success (look up the OK Plateau). Do NOT bet your ass on something you read online (or hear in casual conversation on the docks). Do NOT make it more wrong and more deeply held by parroting it for tribal participation points. Make your default assumption for how someone tells you (insistently.. authoritatively) how to deal with something electrical to be "idiot". There is zero up-side to any other strategy. No LIKE buttons down at the morgue.
One of my closest friends who knows my academics and professional background lectured (insistently) that it's FINE for him to tie ground and neutral together "because they're tied together at the box". I can draw a picture in <5 seconds how you screw someone (else) with that idiot move. I refuse to go into his home or business anymore (need more polite made-up reasons if you got any). Three winters ago, I found a "dynamic" ground fault in the (raped and left for dead) panel in my boat yard when I plugged in. Came and went and I know... the way a scientist uses "know"... that I can demonstrate a half-dozen irrefutable ways my boat was solid on this matter. I put in an amount of time collecting the data and diagnosing and writing it up that I'd get paid $30k to do "on the clock". Be useful is the 11th Commandment. "We sent an 'electrician' down to measure it and he said it was fine". Giddyup humans. Exact same effect for the next guy as my ground-neutral-confused friend. Fast forward to spring and I pull up to my boat in the yard and there's a literal fog of guys dressed like electricians (and therefore... they must be electricians... it's like Harley riders. It's all about the fashion) staring at the panel trying to figure it out.
People really really suck at electricity once one departs the realm of the flashlight. In my 5 years at a marina, I cannot not believe it's 10,000x worse there than on land. Everyone knows everything (those clothes the emperor has on... AWESOME!)... not. Everybody (with Google) knows that... not. The service providers... God's gift to electricity... not. You have the confluence of MULTIPLE non-cooperating electrical standards at your boat/dock... terrestrial AC... marine AC... marine DC.. bonding... signal grounds... electrical grounds... communication grounds.. lightning grounds... and you're surrounded by electrolytes and the hyper-naïve who are vastly more prone than they are on land to just SCREW with things regardless of how little they understand about it. None of the standards for these environments appear to care about how they interface to the other. I've been around standards committees for a long time. You don't always get the best/brightest. Sometimes you do... but they're usually representing their employer. They're motivated by their careers... not by science or the needs of the community.
Your boat... my boat... scary fricking places. The no-man's land between the dock plug and your boat... scary. I look at the design of those connectors/cords (lightning generators) and cultural practices and I literally can't wait to sell my boat and hang out elsewhere. I'm starting to shotgun here... let me try to stick to the point.. tribal electrical "knowledge". It is massively likely you don't have the ACTUAL big picture in mind when you contemplate electrical or decide something you read from someone you don't know "sounds good", so please do yourself and your friends and the guy on the next boat a huge favor and leave it the hell alone. There are more things in heaven and earth... AND... the standard-issue human mind has some really serious mechanisms hard wired right in to drag you off the path to the right answer.
Not trying to pick on people... just our species. The human mind is not a mysterious thing. Stupidly predictable. It's your ass... for the same reason you aren't going to jump in and take a swing at spinal chord surgery on your spouse, don't think the world of correct and (CRITICALLY) failing electrical system behavior is accessible to you if you don't do it all day/every day. The failures are stochastic.. you aren't guaranteed to kill someone. Just more likely.
Hobby thinkers/designers are an off-the-scale hot button subject for me, especially when they are willing to ignorantly storm into the darkness and screw with things that move risk to others who did not sign up for it... I'm going to not be opening this list for a while because I simply don't want to talk about with "civilians" beyond one simple warning. Sorry if it seems rude.