Check those shorepower plugs...!

That's some nice forensic detective work.

As far as the cost difference, the words "Marine" bump it up $380, that's about $63 per letter!

Would have to dig in the A.B.Y.C. rules to see if the Marine specs vs. Industrial spec really warrant the additional cost.

Industrial connects are not UL rated. Nor rated for marine. If that potato has ever a claim, these issues will be looked at.
That said, I have shopped the internet and found bargains when not in a project hurry.

My last project was a 3 phase to single phase converter box. All components UL and marine rated. So I have shopped for a few 5 and 4 pin connects.

Yep. But you already knew this long ago.

There are 4 wires......so $2ft x4 x100= $800 in wire plus the connectors, plus the boots, etc. They don't sell nearly as many 100amps which drives the prices I guess...…. Look at the price difference between a 30 amp cord and a 50 amp cord......10x the price.

The Marinco ends are a hell of a lot easier to change than the Hubbell.

Having personally dealt with U.L., they are quite expensive on getting things tested and listed. I'm sure the "marine" testing at U.L. is rigorous and it is very time consuming just dealing with U.L.
Once you are U.L listed you continued to get billed by U.L. for unannounced plant visits/inspections and other maintenance fees. And U.L. knows how to bill! This I think is a contributing factor to the price for marine U.L. stuff...but , I would also have to agree , new to me, that Boat stands for Bend over and take it AND like it! Lol

What I see in the first picture the wire was not inserted far enough into the plug...……...look at the hex set screws closely , the second one in both wires is turned in much deeper suggesting only the fist set screw was engaged with the wire.

The Glenndenning cords come in 60' and 100' lengths from Glenndenning. Most boats have 100' as you lose 10' or more by the time it's routed through the cablemaster into the drum and out of the drum to the boat's electrical connection.

I was told that the difference btwn the industrial 50 amp 125/250v cord and the marine version is the prongs on the ind. are not plated but only brass. the marine are nickle plated ,I think.

In the old days. I have not found tinned wires in a marine shore power cord in a long while.

I goofed (wire & Pins).
Yes, the PINS are plated for marine connects. This helps to keep the corrosion down.
THEY DO STILL NEED CLEANING.
It's been a while since I have handled Tinned wire cable.

I try to keep my connectors dry and gooped up with dielectric grease.

Watch that grease. It will collect dirt/contaminates and hold it.
We recommend to our customers vigilant inspections of shore power connects and pins. When in doubt, clean with contact cleaner and apply a thin coat of grease.
We also recommend to our 30 & 50 amp connect customers, rotate the power connect a few times before clamping down the weather ring. 100 amp customers to push/pull the big connector a few times before clamping down the weather ring.
This helps wipe the contact surface of old bugs and somebody elses connect grunge. It's scary to look into a transient docks power connect sometimes.

A couple of our customers we tear down the 100 and some others 50 amp connects for inspection. Routine with oil change for a few.
It's scary what we find.

Oh, molded male 50A plugs on powered retrieval systems for some reason are the worst.
When they fry, they fry big time.
FM Toast.
Don't have the data yet to blame the mfg or the customer.

Great post Pascal .

Just opened up both ends of my 32 A EU spec Marinco ,s to find the boat end earth disconnected.

Wire was in the clamp ,it had fractured/ snapped and just came out .
Maybe insitu it had continuity? Point is who knows ?

Cut back about 1 inch all ends ( even if they looked fine ) and refitted checking both screws gripped at the dock end .

So yup all should do at least an annual check .