Plugs and Receptacles for Wet Locations

[TugboatEng]

I'm curious to hear opinions (or rules) on plug materials for potentially (not continuously) wet environments. This is a 480V grounded 3P4W application.

I am changing from a disconnect switch and plug to a switching duty plug. Currently when a wet plug is inserted and the plug energized by the disconnect the plugs sometimes burn out internally. The operators hands are not on the plug during this fault.

With the new style plug, the operators hands will be on it while it is being energized (no more manual disconnect). I feel that grounded metallic plugs would be safer in this case. The receptacle will be installed on a metallic enclosure. We have always used metallic plugs in the past but this new product has both poly and metal options.

 

[Sparweb]

This might be a solved problem in aviation, if you're interested in trying the circular connectors available to us.
Not sure about 480V, though - Aircraft AC electrical systems have 208VAC line to line, typically.
Common Manufacturers: Cannon, Amphenol, Glenair (and many others)

This actually refers to US Navy applications:
Glenair:

https://www.glenair.com/shipboard-interconnect-and-conduit-solutions/index.htm

 

[3DDave]

"switching duty plug"

Is there an example, maker, company? That seems like a lot of mechanism to build into a connector.

Is this salt-water wet?

 

[TugboatEng]

Sure, I'm looking at purchasing the Metric DS60 plugs and receptacles. They're very common in the marine industry but most users purchase plastic plugs. I feel that the metal plugs may be safer. I plan to install better lighting at the stations so the crew members can see if the plugs are wet before inserting.

DS60 Switch-Rated Plugs & Receptacles – 60 A - Meltric

https://meltric.com/media/contentmanager/content/meltric-catalog-ds60-en.pdf

I will also be scheduling a visit from the sales rep.

 

[FacEngrPE]

The Meltric catalog states in the washdown duty section
"Type 4X/IP69/IP69K rated watertightness as soon as the plug and receptacle are mated, or when the receptacle lid is closed."
If you really need to connect wet electric receptacles you need to consider wet mate rated devices, which are usually applied to undersea applications.

 

[TugboatEng]

The issue we have is that the plugs are stored on the exterior of the vessel and sometimes get wet when not mated. In my 15 years at this company I can think of 4-5 incidents of wet plugs being mated and causing damage to the plug. We're currently using NEMA twist lock plugs so anything is going to be an upgrade. The Meltric plugs have covers but my experience with Appleton is that the covers are mostly cosmetic. With that said, Appleton and Meltric have superior cord side sealing than the twist lock plugs. I'll do everything I can to prevent the plugs from getting wet but I want to make it as safe as possible if a plug is wet.

 

[stevenal]

Have you considered installing non-powered receptacles at the storage location?

 

[jraef]

The way the Meltric system works, inside of the receptacle portion there are movable contacts, like a contactor, that only close AFTER the plug body is fully inserted. That’s how they are rated as a disconnect switch without needed an actual handle operated switch. But I don’t think that will help if the plug body is filled with water when you insert it.

In theory, if you have the receptacle pointed down and the operators simply make a habit of pointing the plugs downward at the last second before turning it upward to mate with the receptacle, they will be draining any collected water in the plug body before inserting it. If they can’t even handle that much responsibility, maybe they need better training?


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