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Arcing in 30A Shoreplug Hotwire Terminal


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That's my theory anyway. This was done by me a couple of years ago but found today as I wanted to make a custom connection without spending another $40. But noooooh. This was a genuine Hubbell plug, proving once again your equipment is only as good as your installer. 

"Well, anyone can wire up a plug ffs." 

Maybe not. This kind of thing can ruin yer night. Along about 0 dark 30. In the rain.

 

USER_SCOPED_TEMP_DATA_MSGR_PHOTO_FOR_UPLOAD_1611959274878.thumb.jpeg.3edd0eca979b390c0c14163c97da32ce.jpeg

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I've had similar things happen on my boat on a couple of occasions:

  1. Bad connection inside plug or between plug and socket caused plug to melt; and
  2. Fatigued cord melted adjacent to the plug, presumably from frequent bending and twisting motion that weakened the wires

So it pays to keep your cord and plug in good condition! I also put dielectric grease on the contacts which seems to help.

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1 hour ago, hard aground said:

Yep. I'm with you. The connection on the boat side of cord is a SmartPlug. The receptacle was under water when previous boat sunk. I didn't bother to salvage it but I'll put that system back in new boat. Love the really solid connection on the end that moves around at the dock. Boat needs elec upgrades from '81 and I'm now on full alert on crappy connections. I shop with MaineSail. His observations, etc are golden. THX

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2 hours ago, See Level said:

Doesn't look like an arc, looks like heat build up in a sketchy connection.

I recall the black wire really didn't want to go in the hole. I crammed it in. This was the result: too much heat as you say and being in a hurry caused it. Probably should have also cut cord back for cleaner wire. I can live with $40 dollar fixes for dumb moves. Maybe a cheapy Asian plug would have caused a  fire. Thx

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14 hours ago, Blue Crab said:

That's my theory anyway. This was done by me a couple of years ago but found today as I wanted to make a custom connection without spending another $40. But noooooh. This was a genuine Hubbell plug, proving once again your equipment is only as good as your installer. 

"Well, anyone can wire up a plug ffs." 

Maybe not. This kind of thing can ruin yer night. Along about 0 dark 30. In the rain.

 

USER_SCOPED_TEMP_DATA_MSGR_PHOTO_FOR_UPLOAD_1611959274878.thumb.jpeg.3edd0eca979b390c0c14163c97da32ce.jpeg

Don’t stick naked wire into a clamp socket

use a wire  Ferrule 

 

 

 

1E691A2A-10CD-4FA6-90D8-DC9973FB7426.jpeg

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 Was this covered in the 12v Bible? I'm embarrassed that I didn't know this. Plus now I can buy more tools! Thank you, Captain. I see You Tube is all over this. Guess those plug holes aren't too small after all. Gracias.

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3 hours ago, Blue Crab said:

 Was this covered in the 12v Bible? I'm embarrassed that I didn't know this. Plus now I can buy more tools! Thank you, Captain. I see You Tube is all over this. Guess those plug holes aren't too small after all. Gracias.

Octagon ferrule crimps are the most versatile 

components like plug and terminals naturally get hot . This  hot cold cycle causes mechanical connections to become loose ...a  high resistance connection 

frequently re torque these fasteners 

 

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1 hour ago, slug zitski said:

Octagon ferrule crimps are the most versatile 

components like plug and terminals naturally get hot . This  hot cold cycle causes mechanical connections to become loose ...a  high resistance connection 

frequently re torque these fasteners 

 

I am no longer proud of my google-fu. Octagonal? Turned up nada. What's yer source Slug? Plus my application is for 10 ga 3 wire plug the hole the ferrule has to go in is ~.125 round hole. Maybe. Am I being a dunce here or what?

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17 minutes ago, Blue Crab said:

I am no longer proud of my google-fu. Octagonal? Turned up nada. What's yer source Slug? Plus my application is for 10 ga 3 wire plug the hole the ferrule has to go in is ~.125 round hole. Maybe. Am I being a dunce here or what?

I should have written hex 

Oct was on mind because i was  ordering octagon junction box 

 

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The ferrules are a fine thing but shouldn't be necessary.  You do have to insert the wire all the way and torque the screw properly.  I've installed dozens if not hundreds and haven't had one fail.

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3 hours ago, 2airishuman said:

The ferrules are a fine thing but shouldn't be necessary.  You do have to insert the wire all the way and torque the screw properly.  I've installed dozens if not hundreds and haven't had one fail.

I heard BITD, they would strip the wire, hit it with solder and stick it in the hole. I started thinking someone had made a better mousetrap. And perhaps so.

10 ga we're talking into a dock plug.

However, the crimped ferrule would have to reduce the wires fresh out of the girdle of sheathing to less than an 1/8" [max] in dia to fit in the (plastic) female side and that would all but compress it into a solid bar. It's soft. Sounds like best conductivity you could have.

Per contra, I looked inside the hubble and there is a metal strip inside of the cylinder wall that each of 3 wires are terminated to. ... opposite the torqueing screw so the un-ferruled wire has maybe 50% conductivity of the ferruled connection. Maybe that's plenty?

 

Please say more about:  "torque the screw properly."

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11 hours ago, slug zitski said:

Don’t stick naked wire into a clamp socket

use a wire  Ferrule 

 

 

 

1E691A2A-10CD-4FA6-90D8-DC9973FB7426.jpeg

Try fitting that in the plug case.....usually no room for that.  You barely have enough space to strip the wire back.

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36 minutes ago, SEC16518 said:

Try fitting that in the plug case.....usually no room for that.  You barely have enough space to strip the wire back.

That's my experience so far. It does look clean though. It's always great to see nice workmanship. 

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5 hours ago, 2airishuman said:

The ferrules are a fine thing but shouldn't be necessary.  You do have to insert the wire all the way and torque the screw properly.  I've installed dozens if not hundreds and haven't had one fail.

I missed this clue :"You do have to insert the wire all the way ..." [ to the bottom of the wire chamber]

Counting the torque screw and the strip opposite, there has to be a third metal strip across the bottom.  

The all around metal ferrule has to be superior to multistrand copper wire touched, at least? at best? at 3 points.

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2 hours ago, Blue Crab said:

Please say more about:  "torque the screw properly."

https://hubbellcdn.com/installationmanuals/WIRING_PD1651_INSTALLINST.pdf

18 inch-pounds just like it says in the instructions.  That's pretty tight.  The usual mistake people make, is that they don't get them tight enough.

I like to let them sit for a minute then retorque them because that is enough time for the metal to flow a little and loosen up the assembly.

 

1 hour ago, Blue Crab said:

Counting the torque screw and the strip opposite, there has to be a third metal strip across the bottom.  

Maybe, maybe not.  Doesn't matter because the wire isn't held against it with enough pressure to get a low-resistance connection.

Quote

The all around metal ferrule has to be superior to multistrand copper wire touched, at least? at best? at 3 points.

The usefulness of the ferrule is that it holds the strands together so that inserting all of them into the clamp at once is easy and reliable.  They are especially useful in environments where the wiring is changed around frequently since it becomes harder and harder to get the strands to behave every time they are clamped in place.  They are also useful for use of particularly fine, small wire at or near the bottom of the size range for the clamp as they help the wire hold a roundish shape.  These things make them useful in industrial applications for both power and control wiring.

They do not necessarily provide a lower resistance or more reliable connection overall.  The area of the ferrule in contact with the clamp isn't any greater than the area of the wire that would be in contact with the clamp, not reliably and consistently so anyway.

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2 hours ago, Blue Crab said:

I heard BITD, they would strip the wire, hit it with solder and stick it in the hole.

 

For what it's worth, Hubbell specifically says not to do that.

One problem is that tinned wires aren't always an optimal shape and so the contact area can end up being too small.  The other is that the flux poses a problem unless it is removed, and outside of a manufacturing/production environment it is unusual for electricians to deflux things they have soldered.

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On 1/29/2021 at 4:59 PM, Blue Crab said:

This was a genuine Hubbell plug, proving once again your equipment is only as good as your installer. 

"Well, anyone can wire up a plug ffs."

 

Sometimes I work as a stage electrician.  Venues vary in the kind of connectors they use for lighting equipment but twist-locks are one of the common types (along with Edison and stage pin).  Every time I install a connector on a cord, I do it with the knowledge that doing it in a sloppy or unprofessional matter could cause a fire.  My two biggest fears, as a stage electrician, are burning down the theater and having things fall on people (either the talent or the audience).  And so I am careful and particular about connectors and cords.  I will not reinstall connectors that show signs of deterioration.  I strip back wires until they are clean and bright and if a strand breaks off I start over.  If I have unqualified people help me install them I inspect them closely for proper seating of the conductor and sufficient torque before final assembly. 

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10 hours ago, SEC16518 said:

Try fitting that in the plug case.....usually no room for that.  You barely have enough space to strip the wire back.

Ferrules come in a variety of configurations suitable to different applications

the original picture was an insulated ferrule 

uninsulated ferrule are also available 

They both accomplish the same task , compressing the stranded conductor and preventing the destruction of individual wire stands 

 

 

F86857D0-260C-41E3-BD11-AAB23BB622AF.jpeg

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You could get a bad crimp in the ferrule and have the same thing happen.  Using the bare strands is fine as long as it is done properly, like everything else.  I have made up a countless amount of 30A plug ends (Electrician by trade) for generators and such, never had an issue.

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Later yesterday I checked at Ace and lo! They only had one size ferrule but it was in fact for 10 ga. No crimper for sale but my guess is the crimper would have to reduce the ferrule/wire by about half to fit in the Hubble plug chambers. 

I found that "industrial" 30A plugs don't fit in the marine receptacles. The blades look alike but are slightly larger. However, the price difference isn't enough to bother getting out a file.  And, obviously, weather proofing is a factor. 

Good read guys. Thanks!

 

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3 minutes ago, Blue Crab said:

Later yesterday I checked at Ace and lo! They only had one size ferrule but it was in fact for 10 ga. No crimper for sale but my guess is the crimper would have to reduce the ferrule/wire by about half to fit in the Hubble plug chambers. 

I found that "industrial" 30A plugs don't fit in the marine receptacles. The blades look alike but are slightly larger. However, the price difference isn't enough to bother getting out a file.  And, obviously, weather proofing is a factor. 

Good read guys. Thanks!

 

I avoid those goofy American  plugs and use these 

 

31E18D6C-CCA5-4B2C-BB32-919DB5BA1E14.jpeg

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I expect we'll see Hubbell do a nice copy of the SmartPlug now available. Talk around beer cans yesterday was how the Hubble product is heavier duty than Marinco. If I were installing 50/100A stuff, I'd think the Hubble prices were just the price of admission. My goal is to use much less juice from the dock in the future anyway. Too easy to get too comfortable. 

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The hot line side is not always the plug, over length cords, two together or bad protection boat side or pier.  Just ends up cooking it.

Ferrules are also called stake ons if you actually want to use greenlee is a good company for tools etc. I think mcmaster sells.  They are pretty much standard on everything on ships up to a lugged connection.  European boats much longer US ones are slowly getting there.  I wouldn't use them for something like this no reason. If it's a screw terminal connection like the hubbel one Z posted they are nicer as it is much more solid but for the normal 30amp with the clamp flat there is not much to gain.  The collar less ferrul like Slug showed would be a maybe.  If I had them I would probably use as the wire is not tinned etc.

 

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