Overheating shore power cable, surge protector

[Rich W.]

My recommendation is reduce the power demand in high temperatures!

SO Cable Selection Guide

temcoindustrial.com

or cable length.

 

[Kevin D Pem]

or cable length.

Yes thhn, conduit, and pedestal! Is the right way to do this job.

 

[Rich W.]

It may not work for the OP’s situation, but I installed this:

 

[Wemustrv]

OK, the mfgr choose that gauge for the cord, but........... Have you ever reached down and unplugged your vacuum cleaner right after turning it off? Notice how the plug AND cord feels a bit warm? That's because manufacturers engineer things right to the safety margin. Can 6 gauge carry 50 amps?.....yes, but it's right at the margin. They save money over the manufacturing run that way, and the problems-in-the-making are yours to deal with and correct, if you're so inclined.
If that 6 gauge cord were only 100 feet, I'd feel better about it, but 150' is pushing things. That being said, I suspect the mfgr. calculated in (or out) a certain percentage on the assumption you would hardly ever be pulling 50 amps through the cord for 3 hours. (Nat'l Electrical code says anything over 3 hours is not "temporary".) To my brain, that's fudging things a bit, but I'm kinda opinionated.

Oh, and for the record, that 150 foot cord has to be considered 300', as the current has to travel out, and back, in order for it to do the work of operating your electrical system. That's where Rich W's voltage drop figures come in.

And Wemustrv is right to be cautious, but maybe a touch over-reactive. I think I would have ALL FOUR cord ends inspected at the very least. (Meaning the cord ends and receptacles, male and female.) That way, potential problems can be corrected or replaced right then, not when it starts showing heat damage the next time. (Tighten all the terminal screws, look for signs of heating, etc.)

Just me talking.....Roger

I have 47 years of experience with circuit breakers and electrical systems as well as sitting on NEC/ NFPA and UL code panels. This is not really overreactive. This is serious problem. See photos to see what bad connections and the heat caused by it can do. These are from my coach which due to a short to ground came close to burning my RV to the ground. The second photo it appears the cable is close to the turbo pipe it is just the angle. While this was not caused by a faulty plug it does show the heating effect.

 

[bpaikman]

For those that actually know what they are talking about!!
The electrician talked about temperature for a reason. Generalization can get an electrician in trouble, the reason for my first sentence!

When you suggest replacing wire maybe you should look at prices. Below is a chart, if you can understand it! Please remember these wire size charts are for 86 degree temperature, not the over 100 recorded by the poster.

Just because the wire is sized right at 86 degrees, it is not a one size fits all. At temperatures in the hundreds your cable is undersized so you should plan to either calculate max power for the temperature, and use less power, or increase cable size...(not a popular option).

It may be interesting for sake of argument to check the prices and weight of the cable, before suggesting the latter.

My recommendation is reduce the power demand in high temperatures!

SO Cable Selection Guide

temcoindustrial.com

we decided to reduce power and covered the cable that was not in the shade with whatever we could find it lying around to shade it

 

[bpaikman]

I have 47 years of experience with circuit breakers and electrical systems as well as sitting on NEC/ NFPA and UL code panels. This is not really overreactive. This is serious problem. See photos to see what bad connections and the heat caused by it can do. These are from my coach which due to a short to ground came close to burning my RV to the ground. The second photo it appears the cable is close to the turbo pipe it is just the angle. While this was not caused by a faulty plug it does show the heating effect.

Wow … yeah we don’t like seeing heat issues with electrical. We bought a temperature sensor device and will be keeping a close eye on it.

 

[bpaikman]

Ok this is the wife passing on the info. I didn't remember that the 120' is comprised of 3 separate cords, all built for us locally by the 'top' electrical contractor in our area. They assure us that the cords are adequate for our needs. Dunno if that means anything.
The reason that there are three cords because they are so heavy - each one is plenty of weight to manage. He bought a heavy duty wagon to tote them back-and-forth from the garage.
We ran only one AC, shaded the cord. we're considering burying it.
We only use the cord for loading, so we can have AC and start cooling the fridge, without bothering the neighbors with the generator noise.
we are three days down the road now, and looking back on it ...we were in extreme conditions.

 

[Rich W.]

On adequacy I’d say they guestimated and didn’t do any calcs - they are off by almost 40’ for 6awg. That size cable would be fine for 30 amps to 140’. Also those extra connections (plugs) are a potential source of additional resistance so that may be part of the problem. An electrical engineer might enter those into the calculations further limiting the use of 6awg.

For outside, non-permanent use where you can watch it, its ok for the fridge, other small 120v stuff, and one AC unit (think 30 amp service), but still monitor it closely to avoid melt-down (or worse). And as a word of caution, never bury anything but direct burial cable.

Re-reading your original post reminded me to ask about your home 50amp circuit. How far is it from your panel, and what gauge wire was used to install it? The reason there was no evidence of excessive heat at the house end is because heat is generated at the load end and resistance which increases with the length of the run.

Edits:

So, re: “4.…Do you think that prong caused all that melting? ”. Answer is no, the prong was overheated by the resisitance caused by carrying an excessive load for that size wire. So the heat build-up damaged the plug - the plug didn’t cause the heat build-up.

I’m guessing you don’t have an energy management system in the coach since its not listed on the brochure even as an option, and was an option on the 2014 Ventana. If you did it would most likely start load shedding and you’d be able to see the voltage at the end of your 120’ run while operating your ACs - btw 13.5 or 15k btu?

As a test, when you get home check the voltage at a 120v outlet in the coach with both ACs running - that will really answer the question. In the mean time, happy travels!

 

[bpaikman]

On adequacy I’d say they guestimated and didn’t do any calcs - they are off by almost 40’ for 6awg. That size cable would be fine for 30 amps to 140’. Also those extra connections (plugs) are a potential source of additional resistance so that may be part of the problem. An electrical engineer might enter those into the calculations further limiting the use of 6awg.

For outside, non-permanent use where you can watch it, its ok for the fridge, other small 120v stuff, and one AC unit (think 30 amp service), but still monitor it closely to avoid melt-down (or worse). And as a word of caution, never bury anything but direct burial cable.

Re-reading your original post reminded me to ask about your home 50amp circuit. How far is it from your panel, and what gauge wire was used to install it? The reason there was no evidence of excessive heat at the house end is because heat is generated at the load end and resistance which increases with the length of the run.

Edits:

So, re: “4.…Do you think that prong caused all that melting? ”. Answer is no, the prong was overheated by the resisitance caused by carrying an excessive load for that size wire. So the heat build-up damaged the plug - the plug didn’t cause the heat build-up.

I’m guessing you don’t have an energy management system in the coach since its not listed on the brochure even as an option, and was an option on the 2014 Ventana. If you did it would most likely start load shedding and you’d be able to see the voltage at the end of your 120’ run while operating your ACs - btw 13.5 or 15k btu?

As a test, when you get home check the voltage at a 120v outlet in the coach with both ACs running - that will really answer the question. In the mean time, happy travels!

Agree. All we need, even on the hottest days, is 1 AC, frdge, and a few interior lights.
House 50amp - about 6 inches from panel. Don't know how it's connected.

 

[bpaikman]

Agree. All we need, even on the hottest days, is 1 AC, frdge, and a few interior lights.
House 50amp - about 6 inches from panel. Don't know how it's connected. (not sure ac btu, probably the smaller?) Not sure about load management - we do know that it cuts off at a 30amp campground if you run both Acs. Probably has nothing extra.

 

[Kevin D Pem]

On adequacy I’d say they guestimated and didn’t do any calcs - they are off by almost 40’ for 6awg. That size cable would be fine for 30 amps to 140’. Also those extra connections (plugs) are a potential source of additional resistance so that may be part of the problem. An electrical engineer might enter those into the calculations further limiting the use of 6awg.

For outside, non-permanent use where you can watch it, its ok for the fridge, other small 120v stuff, and one AC unit (think 30 amp service), but still monitor it closely to avoid melt-down (or worse). And as a word of caution, never bury anything but direct burial cable.

Re-reading your original post reminded me to ask about your home 50amp circuit. How far is it from your panel, and what gauge wire was used to install it? The reason there was no evidence of excessive heat at the house end is because heat is generated at the load end and resistance which increases with the length of the run.

Edits:

So, re: “4.…Do you think that prong caused all that melting? ”. Answer is no, the prong was overheated by the resisitance caused by carrying an excessive load for that size wire. So the heat build-up damaged the plug - the plug didn’t cause the heat build-up.

I’m guessing you don’t have an energy management system in the coach since its not listed on the brochure even as an option, and was an option on the 2014 Ventana. If you did it would most likely start load shedding and you’d be able to see the voltage at the end of your 120’ run while operating your ACs - btw 13.5 or 15k btu?

As a test, when you get home check the voltage at a 120v outlet in the coach with both ACs running - that will really answer the question. In the mean time, happy travels!

I disagree with this thesis!

My argument is that heat is produced at the point of resistance. Said heat will only be carried as far as it takes to dissipate. Thus the wire will suffer only as far as the heat will be carried.

The rating of the wire is based on the brake down of the insulation, and it's ability to dissipate the heat produced.

If the cord cap is getting hot enough to melt the structure of the cap, then that is the resistance needing to be addressed.

Let me give an example! Most of us have used a space heater. Do you see a brake down of the supply cord because the element is cherry red! No you don't, and the reason is obvious, the cord has nothing to do with the desired resistance. In fact without the resistance in my example we would have a short circuit.

The laws governing our circuit are not a mystery, they have been well understood for many years. Our run is sized based on voltage drop, because resistance creates heat, and that reduces the power at the end of the run(the resistance becomes part of the circuit and heat increases resistance in a wire)!!!

Folks, it really is that simple!!! Add this knowledge to your assessment and you will realize. The wire is as good as it was when new,it has not been stressed! Only the cord caps and the wire back to the point of insulation damage, no further!!!

It might serve you to know if the cord caps were not exposed to anything flammable, the most damage that would occur would be a flipped breaker when it shorted out!!!

I took the time to make my opinion known because I am frustrated by fear mongering that serves no common good!!!

 

[Rich W.]

I disagree with this thesis!

My argument is that heat is produced at the point of resistance. Said heat will only be carried as far as it takes to dissipate. Thus the wire will suffer only as far as the heat will be carried.

The rating of the wire is based on the brake down of the insulation, and it's ability to dissipate the heat produced.

If the cord cap is getting hot enough to melt the structure of the cap, then that is the resistance needing to be addressed.

Let me give an example! Most of us have used a space heater. Do you see a brake down of the supply cord because the element is cherry red! No you don't, and the reason is obvious, the cord has nothing to do with the desired resistance. In fact without the resistance in my example we would have a short circuit.

The laws governing our circuit are not a mystery, they have been well understood for many years. Our run is sized based on voltage drop, because resistance creates heat, and that reduces the power at the end of the run(the resistance becomes part of the circuit and heat increases resistance in a wire)!!!

Folks, it really is that simple!!! Add this knowledge to your assessment and you will realize. The wire is as good as it was when new,it has not been stressed! Only the cord caps and the wire back to the point of insulation damage, no further!!!

It might serve you to know if the cord caps were not exposed to anything flammable, the most damage that would occur would be a flipped breaker when it shorted out!!!

I took the time to make my opinion known because I am frustrated by fear mongering that serves no common good!!!

No fear mongering in any of that Kevin - just the difference between trial and error while stressing equipment and melting things vs building a trouble free system based on established standards that you know will carry the load safely and efficiently.

 

[Kevin D Pem]

No fear mongering in any of that Kevin - just the difference between trial and error while stressing equipment and melting things vs building a trouble free system based on established standards that you know will carry the load safely and efficiently.

Yah but when we experiment with most cords, when sized for amps, the cord cap connections are the ones that let the smoke out