50 or 30 amp - R-pod Owners Forum

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offgrid

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Topic: 50 or 30 amp
Posted: 03 Feb 2019 at 7:57am

I don't think anyone is saying that you're going to hell if you use a dogbone.

I'll let lostagain speak for himself but for folks living in the far west the last couple of years electrical fires have been a really big deal. He may be thinking about the cause of the Tubbs fire in 2017 which up until the Camp fire this year was the largest in CA history (22 deaths, 5600 buildings, 37000 acres).

A report recently came out that that fire was started not by the now bankrupt utility PG&E but by privately owned and maintained power equipment connected to PG&E gear on private property, which had not been installed and maintained by a licensed electrical contractor. The details of what was and wasn't actually done haven't been made public yet and maybe never will be, but regardless, the folks involved in that must feel like they've already gone straight to hell. I will hazard a guess that they will most likely be defendants in litigation for decades if they live that long.

So I took lostagain's post as a voice of caution meant with the best of intentions.

As far as this thread is concerned if you notice my very first post was to refer the OP to the previous thread on this subject. I will however continue to post if I read statements which incorrectly conclude that there is no fire risk associated with connecting 30A rated circuits to a 50A supply and that its OK to ignore warning labels on your trailer without considering the ramifications. Its not that I foolishly think that I will change the opinions of any of the few stubborn old guys still following this thread, I'm one of those too so I know how hard that is.

Everyone is entitled to their own opinions but not to their own facts. So as a professional in this field I will continue to try to convey the facts and separate those from opinion. I don't want to wake up one morning and find that one of our new member's families burned up after making this connection and I could have at least clarified the facts for them but I didn't bother to take the minute or two required to post.

1994 Chinook Concourse
1995 RV6A Experimental Aircraft
2015 Rpod 179 - sold

mjlrpod

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Posted: 03 Feb 2019 at 7:40am

As I posted ONCE, long ago at the semi beginning of this thread, I almost always use a 30 amp to 50 amp adapter. The 3 prong 30 amp plugs into the back side, and there are 4 male prongs on the front side "converting" my 30 to 50. I watched this post go back and forth about it being perfectly ok, or being the scorn of satan. Without "opinion" being part of this, can we answer if there is any "proof" of something being wrong with this. I really woulf like to know if I am "truley" doing something dangerous or wrong.

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Tars Tarkas View Drop Down

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Posted: 02 Feb 2019 at 9:38pm

I'm probably going to regret posting this, but here goes anyway.

I'm sure everything that's been said in this thread so far is true and correct, but maybe it's stretching things a lttle too far to compare using a 50/30 dogbone to driving 100 mph through a school zone or saying that I might be responsible for burning down 14.000 homes if I use a dogbone.

I lobbied, mildly, for the continuation of this thread after it was shut down for beating dead equines, but there is a mostly small group here, who have been just about the only particpants in this thread, except maybe the OP. I gotta say, I think we all know what everyone's position is on the subject. I guess I'm just trying to say that it might be nice if we didn't try to keep hitting each other over the head with just one more point.

I just went to the effort to tally things up. If I counted correctly this is the 94th post on this subject. The OP posted twice, once with the original question and then just a few posts later to thank everyone for their replies. Seven people posted once, mostly long ago. Everyone else has posted multiple times, some more than 15 or 20 times.

I'm totally fine with this thread dying a natural death, even if it lingers another 50 years but it does seem to me that one of the dynamics going on here is that there are only a few people participating in this thread anymore. Aside from the fact that there probably really isn't much useful to add, I think it would be helpful if we realize what a small audience there really is here. I've been around the internet long enough that I have pretty tough skin, and I know this wasn't really anyone's intention, but when it gets to the point that someone basicallysays you're going straight to hell if you use a dogbone (running over kids in a school zone or killing 79 people by causing a forest fire will probably put you on a shortcut to hell, I assume), well, just my opinion, maybe it's past time to give it a rest and move on.

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lostagain

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Posted: 02 Feb 2019 at 6:38pm

When we do risk assessments and decide something is or is not worth the risk, one off the things we always need to bear in mind is that if sh#* happens and someone gets hurt, we need to step up and take full responsibility for it turning out badly. Even when we take personal risks, there are always others to consider. If I choose to go sky diving and splatter myself on the tarmac, it isn't just me who loses [and I'll never know the difference anyway]. My wife, my children, grandchildren, friends and my creditors [enemies] are all affected and it isn't likely to be in a favorable way.

If I choose to take the risk of using a 30/50 A dogbone and start a fire like the Camp Fire in Paradise, CA, well, I better be ready to step up and pay the consequences. Sadly, in some instances we choose to take risks that turn out to hurt someone else and are unwilling or unable to compensate those whom we hurt. Then it's time to blame those dirty ambulance chasing lawyers.

And yes, I realize we take risks every day as mundane as going to the bathroom at night to deciding to drive 100 mph in a school zone or worse. It is impossible to avoid taking risks in life, but by the same token it is impossible to avoid the moral imperative that we should accept responsibility for the consequences of our actions, including the risks we choose to take.

Never leave footprints behind.
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offgrid

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Posted: 02 Feb 2019 at 5:10pm

Yes furpod,

I fully understand that you have not found a case in the RVIA data where a dogbone has been found to be the direct cause of an RV fire. Again, there is a good reason why the NEC requires and the manufacturers apply a warning label not to apply 50A to a 30A trailer connector. And, again, because there has not been a case documented doesn't mean that there hasn't actually been one, and it also doesn't mean that it is a non issue. Obviously, the code authorities and FR think that it is.

I'm totally fine though if you say that in your view it is worth the risk. In my view it is not, and there is an easy way to address the problem and truly make it a non issue if someone wants to. 'Nuff said.

Re 12Vdc electrical system safety, I do agree that is an important subject and merits the creation of a separate thread. I'll be happy to start one unless someone else wants to.

1994 Chinook Concourse
1995 RV6A Experimental Aircraft
2015 Rpod 179 - sold

StephenH

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Posted: 02 Feb 2019 at 11:00am

That's for sure! I accidentally crossed the terminals on a 12V battery once with a wrench. There was a sizeable spark and a chunk taken out of the wrench where it instantly became hot enough to melt the metal.There is a reason DC arc welding is the most common. https://sciencing.com/difference-between-ac-dc-welding-6021349.html

StephenH
Happy is the man that findeth wisdom,...

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GlueGuy

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Posted: 02 Feb 2019 at 10:54am

Originally posted by furpod

Again, yes electrical fires happen.. your statistical average is for all electrical fires. 12v.. yes 12v, is the number one cause of RV fires. By a large margin actually.

Might be related to the fact that for a given wattage, the current on 12V is 10X what is required at 120V. Amperage is what heats up wires.

bp
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furpod

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Posted: 02 Feb 2019 at 8:03am

Again, yes electrical fires happen.. your statistical average is for all electrical fires. 12v.. yes 12v, is the number one cause of RV fires. By a large margin actually.

Again, looking through the RVIA data, I can find NO report of a fire caused by a dogbone. That data only goes back 14 years, and of course only covers what gets reported to them by dealer members, but.. well.. as much as some seem to worry, for most people, it's a nonissue.

Not using hookups at all, ever, still doesn't insulate you from the possibility. In fact it leaves you open to the number one cause of RV fires.

offgrid

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Posted: 01 Feb 2019 at 8:35pm

"There is absolutely nothing that says the fire would be in the Pod, unless it had to do with your cord storage. The fire would be in the power cord, if and only if the scenario was met. There is much more risk to fire when using extension cords to power your Pod. Not denying risk, but miniscule compared to other causes of fire in RVs."

mcarter, perhaps we are not in agreement after all. There is certainly a scenario that could cause a fire in the pod. I explained it. The 30A rated conductors between the trailer connector and the trailer circuit breaker inside the pod are not protected from seeing currents up to 50A and could overheat and cause a fire if a fault occurred somewhere along that cable run, as could the 30A rated power cord and the connectors themselves. If that happened the internal cable overheating is of course much more likely to cause the trailer to catch fire than the cord is.

Re the statistics, clearly this is a low probability event. I don't think anyone disputes that. Since the details of electrical fire causes are not well reported, there may or may not have ever been an actual case, but that doesn't mean it can't happen, it only means its unlikely.

I found an article which reported that there are about 6000 RV fires annually in the US, about 35% of which are caused by electrical problems. RV's are used on average about 20 days a year, and there are about 10 million RV's in the US so that gives an overall probability of having an electrical fire of any type of around 0.001% per day of RV use.

Pretty small number. But for comparison the equivalent number for sticks and bricks home electrical fires is about 8% of that, so sticks and bricks houses are much safer from electrical fires than RV's. Makes sense because RV's have batteries, generators, tighter clearances, 12 and 120V circuits, are subject to wire and connector vibration and chafing, etc.

The important point here is that the reason both numbers are low is because we have a rigorous set of standards that home electricians and RV manufacturers have to follow. The code making panels (I've been on one) are not doing risk/reward calculations using actuarial statistics for the value of human life because their job is to prevent injury and death. When there is a reasonable solution to improve safety they adopt it. In this case, they do this by providing a warning against connecting a 30A trailer to a supply rated higher than 30A.

I choose to acknowledge this warning and not do it, but I've experienced personally and professionally the kind of faults that could cause fires here, and I so rarely use hookups that that doesn't produce any hardship for me. If I did use hookups frequently and started running into problems finding 30A connections I would buy an inline 30A circuit breaker and cable assembly which would keep me in compliance when connecting to 50A.

That's me, we're all grownups here and can make our own decisions.

1994 Chinook Concourse
1995 RV6A Experimental Aircraft
2015 Rpod 179 - sold

StephenH

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Posted: 01 Feb 2019 at 9:42am

Originally posted by lostagain

StephenH, you have a very important need for power and for you, using the 50A dogbone makes sense. I count my blessings that so far, I don't have health issues that necessitate a consistent supply of electric power.

Thank you. My point exactly. One must do a risk/benefit calculation. For us, the benefit far outweighs the risk. For others, the risk/benefit ratio is completely different. That is also why I opted for dual-6V batteries (and learned our first night out on our first long trip that I can't run the refrigerator on 12V even with those dual 6V batteries). So, I also run the refrigerator on propane while traveling and only switch to 110V when it is available.

StephenH
Happy is the man that findeth wisdom,...

ouR escaPOD mods
Former RPod 179
Current Cherokee Grey Wolf 24 JS