50 to 30 amp

[Outback 325BH]

Originally Posted by Hyseas

For the purpose of clarification, I am retired and was a state-licensed electrical contractor. For those wanting additional information, look up "subpanel" in the NEC (National Electric Code). In the case of a camper, I consider the camper's breaker panel (say 30 amp) a subpanel of the campground pedestal panel. The camper's breaker panel is a subpanel because the wiring to it includes concealed (in-wall) wiring within the camper structure that is inaccessible by the occupant. Therefore, the NEC requires that the wiring between a main panel (campground pedestal) and a subpanel (camper breaker panel) be rated to carry the amperage of the main panel's breaker. So if your camper is built for 30 amps, its internal wiring to its panel is only rated for 30 amps (not 50 amps). So the issue at hand are not the circuits protected by the 30 amp camper panel, it is a short or other wiring issue (loose connections being a common one) in the internal concealed wiring prior to the camper's panel.

It doesn't matter that you have a 30 amp cord plugged into a 50 pedestal (via the proper cord adapter) going into a 30 amp coach... because the main breaker in the coach will prevent a draw of more than 30 amps.

If you are concerned about a short in the cordset between the 50 amp pedestal breaker and the coach's 30 amp breaker, that is somewhat valid... but a non-issue in real-life. The only load that would occur there would be from a dead-short in a damaged cord. In that case, the 50 amp breaker in the pedestal would still trip.

You do realize that 30-50 cord adapters have been around for a LONG time and in use by a ton of campers. This is such a non-issue.


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[Hyseas]

"This is such a non-issue." Right, tell that to the camper I repaired where the wiring burned up at the cord-to-NM junction. Thankfully it was in a metal enclosure, so the fire was limited to all the wiring within the box. I suggest you read specifically Article 551 of the NEC that addresses RVs and prohibits the use of 30 amp RV services on anything greater than 30 amp pedestal receptacles. Furthermore, that article specifies the type plug to be used so that it cannot be plugged directly into a higher amperage supply. So readers beware - I'm speaking of facts, not observations or opinions.

[SummitPond]

Originally Posted by Hyseas

I suggest you read specifically Article 551 of the NEC that addresses RVs and prohibits the use of 30 amp RV services on anything greater than 30 amp pedestal receptacles.

Here's a link to the referenced NEC (I could only find a draft 2014, not an approved one):
https://www.nfpa.org/Assets/files/Ab...3-ROPDraft.pdf

Article 551 starts on page 519.

I find it interesting to note that 551.71 (dealing with the types of receptacles available at RV parks) bears no resemblance to what I've observed at many places I have stayed in my travels.

[Outback 325BH]

Originally Posted by ShacterShack

Here's a link to the referenced NEC (I could only find a draft 2014, not an approved one):

https://www.nfpa.org/Assets/files/Ab...3-ROPDraft.pdf



Article 551 starts on page 519.



I find it interesting to note that 551.71 (dealing with the types of receptacles available at RV parks) bears no resemblance to what I've observed at many places I have stayed in my travels.

<sigh>

Nobody cares about your NEC references.

Conversion cords are safe and are WIDELY used by most everyone some time or another.

The "fire" you cite was not caused by a properly functioning conversion cord. Something else was amiss and would have happened without the conversion cord. If there was a short or arc that caused a fire, the same thing would have occurred with a 50 amp cordset. If a breaker didn't trip to protect everything, there was some loose connection or broken conductors arcing. Again, nothing a bigger wire would have prevented.


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[JRTJH]

Originally Posted by Hyseas

"This is such a non-issue." Right, tell that to the camper I repaired where the wiring burned up at the cord-to-NM junction. Thankfully it was in a metal enclosure, so the fire was limited to all the wiring within the box. I suggest you read specifically Article 551 of the NEC that addresses RVs and prohibits the use of 30 amp RV services on anything greater than 30 amp pedestal receptacles. Furthermore, that article specifies the type plug to be used so that it cannot be plugged directly into a higher amperage supply. So readers beware - I'm speaking of facts, not observations or opinions.

In the past couple of years I've been to a large number of RV parks that only have 50 amp service at the site pedestal. Most of them have "loaner adapters" so people with a 30 amp trailer service can connect to the campground service. This past summer, we stayed in several campgrounds that simply don't have any 30 amp sites at all. Are you saying that these campgrounds don't meet NEC requirements for safe camping?

[CWSWine]

I have seen several of those lately and they are usually the newer parks. I have seen some of the older smaller parks only have 30 amp connects and no 50 amp.

Originally Posted by JRTJH

In the past couple of years I've been to a large number of RV parks that only have 50 amp service at the site pedestal. Most of them have "loaner adapters" so people with a 30 amp trailer service can connect to the campground service. This past summer, we stayed in several campgrounds that simply don't have any 30 amp sites at all. Are you saying that these campgrounds don't meet NEC requirements for safe camping?

[plutz3]

https://www.youtube.com/watch?v=7DpIzugALqc

this series really helped me

[ctbruce]

Originally Posted by plutz3

this series really helped me

That's pretty clear and easy to follow. Great help! Are there more from this guy?

Chip Bruce, RPh
Kansas City, MO
2016 Fuzion Impact 312
2015 Chevrolet Silverado LTZ
WELL....THAT WAS FUN!

[hankaye]

Howdy All;

I get the weekly RV Newsletter and within it there are a series of articles by
a guy named Mike Sokol. He's written a series of 12 articles about the "No
Shock Zone" and he also covers a lot of other useful info. Here's a link;
http://rvtravel.com/category/rv-livi...-power/page/2/

On pg.1 there is an article from Gary Bunzer about just this same topic ...

hankaye

[Sherwood]

Originally Posted by Hyseas

"This is such a non-issue." Right, tell that to the camper I repaired where the wiring burned up at the cord-to-NM junction. Thankfully it was in a metal enclosure, so the fire was limited to all the wiring within the box. I suggest you read specifically Article 551 of the NEC that addresses RVs and prohibits the use of 30 amp RV services on anything greater than 30 amp pedestal receptacles. Furthermore, that article specifies the type plug to be used so that it cannot be plugged directly into a higher amperage supply. So readers beware - I'm speaking of facts, not observations or opinions.

I am also an electrician and have read article 551 several times and nowhere does it prohibit plugging a 30 amp camper into a 50 amp service at the pedestal. Can you please copy and paste what you read? As previous posters have stated, the RV main breaker will limit the rated cord set to its 30 amp capacity. Nothing else can cause more than 30 amps on that cord unless tampered with as the cords for our campers are meant to only serve the camper and nothing else. Can you explain how the manufacturers were able to market these adapters if they cause fires like you claim?
As far as the wires burning up in the metal junction box, I would say its because of bad connections causing arcing and then carbon buildup on conductors which causes more resistance thus causes conductors to get excessively hot and then burning of insulation at the joints and in junction box. If it was an over-current condition on the wires, you would see degradation or evidence of melting of the insulation on the wires outside of the junction box. Since it was only within the junction box, it tells me the problem was with the connections. Without seeing the whole thing, one cant be for sure. But one thing I am sure of is that the use of "dog bones" are legal and safe if used as directed and not tampered with.

[notanlines]

Mark my word, the legal department of Camco and Voltec would insure that the company didn't produce and sell these if they weren't safe. They are very common all across the country, virtually at all major RV parks.

[Outback 325BH]

Originally Posted by Sherwood

I am also an electrician and have read article 551 several times and nowhere does it prohibit plugging a 30 amp camper into a 50 amp service at the pedestal. Can you please copy and paste what you read? As previous posters have stated, the RV main breaker will limit the rated cord set to its 30 amp capacity. Nothing else can cause more than 30 amps on that cord unless tampered with as the cords for our campers are meant to only serve the camper and nothing else. Can you explain how the manufacturers were able to market these adapters if they cause fires like you claim?

As far as the wires burning up in the metal junction box, I would say its because of bad connections causing arcing and then carbon buildup on conductors which causes more resistance thus causes conductors to get excessively hot and then burning of insulation at the joints and in junction box. If it was an over-current condition on the wires, you would see degradation or evidence of melting of the insulation on the wires outside of the junction box. Since it was only within the junction box, it tells me the problem was with the connections. Without seeing the whole thing, one cant be for sure. But one thing I am sure of is that the use of "dog bones" are legal and safe if used as directed and not tampered with.

^^ This.

The 30 amp camper can't draw more than 30 amps. It's main breaker will not allow it.

In the case of a short in the cord, the 50 amp breaker in the pedestal will trip... even with a 10 gauge "30 amp" cord.

If loose connections arc and cause a fire??? The 6 gauge "50 amp" cord would not prevent it.


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[Sherwood]

Originally Posted by Outback 325BH

^^ This.

The 30 amp camper can't draw more than 30 amps. It's main breaker will not allow it.

In the case of a short in the cord, the 50 amp breaker in the pedestal will trip... even with a 10 gauge "30 amp" cord.

If loose connections arc and cause a fire??? The 6 gauge "50 amp" cord would not prevent it.


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That is what I was trying to say but shorter. Only thing that can help prevent fires from arcing is arc-fault circuit breakers. And from what I read, they are not required in RV's or at the pedestal as of the latest code update. Bottom line, the use of the 50 to 30 or 30 to 50 adapters are perfectly fine and safe to use.