Shore Power Fun....

[markpj23]

Originally Posted by alank

...Bubba being such a good guy may have added a 50A breaker in place of the original 30A breaker, so it would match the 50A socket. Then we may start to have a problem with the overload. We don't know all the details of what happened.

This is my belief. I was unable to verify before we pulled out but will do so when we get back in Feb.
Many thanks for all the replies to this thread.

[alank]

To add to my post above, I looked up the NyoGel 760G and they do market it as a dielectric grease, about $20 for 1 1/2oz.

Their test was with 1A of current, voltage was not disclosed, but from the plug-in, it was a low voltage, est. 6-12V.

What I would like to see as a test is a 50A plug drawing about 45A on each leg, one prong clean and dry, the other prong coated with dielectric grease, and see if there is any voltage drop across either prong.

Have a good trip Mark, this was a fun thread.

[Bigceasar]

Originally Posted by markpj23

This is my belief. I was unable to verify before we pulled out but will do so when we get back in Feb.
Many thanks for all the replies to this thread.

You said you used a 30 amp extension cord. Those would not connect to a 50 amp receptacle without an adapter. If you plugged the cord into the 30 amp receptacle the entire circuit would be limited to 120 volt 30 amps no matter what you ultimately adapted and connected to. If you connected to the 50 amp receptacle at the pedestal there should never be a 30 amp extension cord in the line to your 50 amp RV. .Something isn’t clear.

[edge68474]

Great read and thread. Thank you. I love reading this type of information.
Ans, I will contimue to use dielectric grease as I have been. At one point in the read, I said " OH SH_T " I have since recovered, LOL.
Thanks gang.

[bigb56]

Originally Posted by alank

So much good discussion here, and the devil may be in the details. I never claimed that dielectric grease prevented an electrical current, just that the best connection was a clean dry connection, then add dielectric grease for corrosion prevention and leakage. This is much like everyone is saying as bigd56 said above, in bolting the battery clamps on tight, then put on the spray paint, not putting the spray paint on everything, then bolt the battery clamp on tight. .

The reason I apply dielectric grease to the battery terminals and clamps before I install them is if you do it after, there is no way to get it to the underside or the tiny voids at the edges of the connection. I have complete faith that the tightening squeezes out any that is on the contact points and leaves it in the voids, thus eliminating a chance for oxygen infiltration. I also do it this way when I make a frame ground, I drill and tap my hole then I put a light coating of dielectric grease on the terminal and on the star washer before I bolt it all down with a machine screw.
Another point for thought, new plug on style circuit breakers come pre greased and the general consensus from some fellow electricians is that it is dielectric. The color matches a dielectric grease which comes clear or light brown, while the conductive greases are generally metallic in color. Additionally most conductive greases for electrical are impregnated with zinc particles which would cause a problem on a copper or copper plated bus.

[alank]

Won't argue with anything you said, and I like the frame ground comment. I like the star washer on the steel frame too, and then cover it all up with grease to prevent corrosion on the steel frame. This might be a good place for a glob of the thicker bearing grease.

I have a small tube of dielectric grease, mine is black and I never have liked the looks of it, and it definitely wasn't in the price range of the NyoGel product. Maybee mine isn't very good stuff.

[twinboat]

Originally Posted by bigb56

I have complete faith that the tightening squeezes out any that is on the contact points and leaves it in the voids,

.

If pressure between the post and clamp squeezed out all the grease, then how does oil or grease protect bearings in engines and gear box's ?

Proper procudure is to put parts together clean and then apply a protective grease.

Sent from my SM-A025V using iRV2 - RV Forum mobile app

[NXR]

Originally Posted by oldenavy

The attachment YC1 provided is very helpful, but it has a glaring error. Their diagrams show the voltage values on the sine waves as peak values but the values we are tossing around are RMS (root mean square), not peak. For example, a typical 120 volt outlet is 120v RMS which is actually about 170v peak (120*sqrt(2)). The diagrams show the peak values to be 120 & 240v.

Sorry to be picky but I teach electric power systems. That company gets 7 points off their homework for not knowing the difference between peak and RMS.

Took the words right out of my keyboard. I wonder how many people will begin quoting that diagram with that massive error.

I get that they did it for simplicity, hopefully, but that is no excuse for presenting bad information.

My question to the OP is whether that place the shore power cable plugged into the extension cord was protected from moisture. I often see those connection points just lying on the ground where they can get rained on or where running water can get in the connection.

Ray

[Ray,IN]

Originally Posted by alank

I have a bit of a different take on all the Bubba connections made here.
The picture of the plug appears to be a 50A plug that has the neutral burned. Normally if the coach 50A plug was put in a properly wired socket, the neutral spade would only carry the current difference between L1 and L2.
Adding a 30/50 adapter takes power only from one slot of the 50A plug and conducts that current through the 30A extension cord. Using a 30A source of power requires you to be very careful about the number of things you try to run in a 100A coach.
The original plug was a 30A plug, which Bubba switched out to a 50A socket, so the original 30A wire was connected to both sides of the 50A socket and in phase. Also in Bubba fashion, he may have switched the original 30A circuit breaker to a 50A circuit to better match the 50A socket. Now you would have 50A of current available to draw through the 30A extension cord that was used. Could be a bit of an overload there.
Since the failure was the neutral prong in the 35/50 adapter, I would suspect the female part of the neutral connection was in very poor condition and provided a very poor electrical connection for the current path resulting in the heat that burned the connection.

I agree, quite possible.

[markpj23]

Originally Posted by Bigceasar

You said you used a 30 amp extension cord. Those would not connect to a 50 amp receptacle without an adapter. If you plugged the cord into the 30 amp receptacle the entire circuit would be limited to 120 volt 30 amps no matter what you ultimately adapted and connected to. If you connected to the 50 amp receptacle at the pedestal there should never be a 30 amp extension cord in the line to your 50 amp RV. .Something isn’t clear.

So a 50 to 30 adapter gives you 120v on one leg. What is the difference between that and just using the 30a extension cord plugged into the 30a receptacle on the pedestal? Not much that I can think of. The RV will still get same-phase 120v (aka bubba 50) on its 50a connection since you must use a 30 to 50 adapter at the end nearest the RV.
Not an optimum connection - as I have learned - but one that will function if I limit loads to just one AC.

[Old Scout]

Mark your final comment worries me a bit--there is a difference. The 50 to 30 adaptor only passes one leg so phasing is no longer the issue. As stated, if "Bubba" was kind enough to replace the existing 30 amp with a 50-amp breaker, then the pedestal is "fused" to 50 amps [one leg] and your coach remains fused at 100 amps total [50 on two legs], so the 30-amp cord becomes your limiting "fuse."

[bigb56]

Originally Posted by twinboat

If pressure between the post and clamp squeezed out all the grease, then how does oil or grease protect bearings in engines and gear box's ?

Proper procudure is to put parts together clean and then apply a protective grease.

Sent from my SM-A025V using iRV2 - RV Forum mobile app

To be clear I only use dielectric grease on automotive stuff although I posted the picture of the new circuit breaker to show it is also used for AC voltage.
As far as using it on the battery terminals it has been a success for me and it's the way the professionals do it as well. There are both opinions freely floating around out there but the proof for me is that it works, and has worked for me for the past 30 years. Here is a professional Ford tech showing the method, and explaining how it works much better than the spray on stuff. (go to 11:56 in the first video).

https://www.youtube.com/watch?v=J74vEOdkq0A

The next video shows the same thing by another mechanic.

https://www.youtube.com/watch?v=fiffUu3G5II

Also the video from Nyojel that I posted in my earlier post shows that dielectric grease does not interfere with conductivity.
I base my conclusions on my own successes and proof from professionals in the industry, not internet hearsay or what some backyard mechanic thinks, and I am still confident I made the correct decision. Some here disagree and that is fine, I have no issue with that, I'm still confident of my methods and will continue to use them while others may do as they believe is correct. It's the American way

[bigb56]

Also in a bearing there is a clearance provided for the lubricant, the lubricant does not create the clearance, it maintains it. In a bolted electrical connection that clearance does not exist, if it did the connection would fail, grease or not.
A dielectric grease does not have the same properties as an automotive lubricating grease either.

[YC1]

Twinboat, to your point. I would guess that a bearing is designed with some thousands of an inch to allow the penetration of lubrication. An improper size crank bearing for example will lock it up.

I'm no mechanic for sure but did take an engine apart once. Slept in a Holiday Inn that night. Just kidding of course but from 50 years of experience and even having some Engineers come up with a fix on some connections that recommended the use of a grease. I don't recall if they used the term dielectric.

It is impossible to get two technicians to agree on how to change a fuse. Soldering a PL259 connector always gets a lot of 'I do it this way".

I bet that is true in the mechanic world as well.