50 amp to 30 amp?

[dasams]

Originally Posted by Arnoldjeff

How does one know how many amps you’re drawing at any given time? Is there a gauge or something to connect to have a constant read on this?

If you buy an EMS surge protector, you'll get real time data on your current draw. I strongly prefer them over the less expensive surge protector. See http://www.progressiveindustries.net/ems-pt30x

[dasams]

Originally Posted by GOUSC

In the "50A Monster" post the OP says their 50 Amp cable is a monster that is too bulky. The OP asks what would happen if they used an adaptor and tried to push 50 Amps over a 30 Amp cable? The consensus solution in that post is that you are asking for trouble as the 30 Amp cable is not rated to have 50 Amps go thru it and there is fire potential.

Just to clarify, an AS with 50 amp service has the ability to pull up to 100 amps. At the pedestal, the 50 amps are at 240 volts. The phases are separated in the four prong plug and pass through the Monster in separate wires. This explains why the Monster cable is so much larger than the standard 30 amp cable. Those who doubt the potential for 100 amps of current need only look in the AS breaker panel where you will see two 50 amp breakers.

[GandW]

I find that surges are rare. Low voltage is the much more common occurrence and can drastically shorten the life of your A/C or heat pump. A good surge suppressor, not the cheap ones, will also disconnect power when voltage is too low or too high and automatically reset when it returns to normal. In just one trip around the US, I hit 3 campsites where voltage was too low. Two times it was a loose connection in the pedestal, which does not show up until under load. The other was a poorly wired campground. If I am going to run A/C I always check voltage at a receptacle before and after the A/C is running.

A cheap surge suppressor is essentially a case to contain an explosion.

[fran&frank]

GOUSC you are more or less correct. If your trailer has a 30 amp service it should be protected by a 30 amp main breaker and if it attempts to pull more than 30 amps that breaker should trip. If you run 30 amps over a 15-20 amp extension cord you are asking for trouble, but when people do use a 15-20 amp cord you are usually plugging into a circuit protected by a 15-20 amp breaker, so that protects it from drawing too much power.

[Mollysdad]

Originally Posted by GOUSC

The way I read both of these, each OP is trying to potentially run 50 Amps of power thru a 30 Amp cable. One solution says its OK the other says you are nuts to do so.

Here's the difference.
Let's say your trailer is wired for 30 amps. It's okay to plug into the 50 amp socket because the trailer only DRAWS what it needs, in this case 30 amps. But the 30 amp plug is different so you need an adaptor, thus the "Dogbone".

The converse is if your trailer is wired for 50 amps and you want to plug into the 30 amp outlet. There's a doggone for that too! But now you have to remember that you only have 30 amps available, even thought your trailer can DRAW 50 amps and potentially pop the breaker or melt the outlet.

[azflycaster]

Originally Posted by Mollysdad

Here's the difference.
Let's say your trailer is wired for 30 amps. It's okay to plug into the 50 amp socket because the trailer only DRAWS what it needs, in this case 30 amps. But the 30 amp plug is different so you need an adaptor, thus the "Dogbone".

The converse is if your trailer is wired for 50 amps and you want to plug into the 30 amp outlet. There's a doggone for that too! But now you have to remember that you only have 30 amps available, even thought your trailer can DRAW 50 amps and potentially pop the breaker or melt the outlet.

I do not agree with the last sentence. The trailer can TRY to draw, but the current will be limited by the 30 amp breaker at the trailer. Also, the outlet will not be melted because it too is protected by the 30 amp breaker at the trailer..

[switz]

A 50 amp 240Vac breaker provides only 50 amp service to the trailer not 100 amp service. Each leg of the 240 Vac cord can have a maximum of 50 amps of current (or 6,000 watts) so the tailer has the potential of 12,000 watts of load at the pedestal.

50 amps x 120Vac = 6,000 watts
30 amps x 120Vac = 3,000 watts

Thus the power cord has four runs of #6 copper wire instead of #2 copper that is rated for 100 amps. The four conductors are neutral (white), ground (green) and the two fused hot legs (red and black).

There are NO 240Vac appliances in a USA model Airstream. Every piece of equipment is 120 Vac of 12Vdc (The European wiring is setup up for 230 to 240 Vac so all their appliances (even my coffee maker in our UK flat) are wired for 240Vac).

So a 50 amp to 30 amp adapter takes power from only one fused hot leg plus the neutral and ground and the wire size is #10 copper. When an 50 to 30 amp adapter is used, there is only 50 amp protection for the #10 wire from the pedestal to the trailer which would allow the wire to fail if an excessive load appeared from the trailer. The main breaker inside the typical single air conditioner trailer is 30 amps which should not overload the #10 wire.

We are not talking about the voltage drop due to the length of the power cord.

Going from a 25' to a 50' 30 amp rated power cord could result in a voltage drop inside the trailer. The largest power draw is the in-rush current required to start the air conditioner.

The 50 amp service in an Airstreams is wired to place one air conditioner on each hot leg to balance the loads when the units start.

[StreaminGeo]

Originally Posted by azflycaster

Everyone should travel with one of these:
https://www.amazon.com/Proline-Femal...ter+plug&psc=1

From now on we will.

[Reeltimer]

Originally Posted by The Ice Man

I thought the 50 to 30 dogbone was a standard accessory and, in fact, my dealer gave us one when we picked up the rig. Surprised you don't have one. No issues whatsoever. In fact, at many full hookup parks the 30 amp receptacles are worn and loose - a disaster waiting to happen. Frequently, when 50 amp is available I'll pick that over a loose 30 amp. The 4 prongs of the 50 are much more secure than the three of the 30.

It's most likely a dealer gift.

[wulfraat]

Originally Posted by Reeltimer

It's most likely a dealer gift.

You are correct… It’s up to the dealer regarding what additional accessories they want to include in the sale to include 15 and 30 amp adapters waste hose, toiletry products, etc. etc.

I believe that the only thing that Airstream will include is the original 50 amp power cord and some tools for the awning, etc.

[Mollysdad]

They're not expensive.
I kept a 50 to 30, a 30 to 50, a 30 to 15/20.

[GOUSC]

Originally Posted by azflycaster

I do not agree with the last sentence. The trailer can TRY to draw, but the current will be limited by the 30 amp breaker at the trailer. Also, the outlet will not be melted because it too is protected by the 30 amp breaker at the trailer..

Thanks everyone for the feedback to my question. It is basically what I was thinking and the feedback explains the "why" of my question. I did want to point out one other factor to consider. In a perfect world you would think the breaker at the source of power or the breaker in the RV would trip if too much power is pushed or pulled.

If you look at post #11 in the "50A Monster" thread there is a video of what can go wrong. This guy had a Class A RV with 50 Amp service. He used a dogbone to connect from his 50 Amp receptacle to a 20 Amp power outlet. He had a 25-50' 20Amp extension cord connected with the dogbone to his 50Amp cable. He then turned on his AC in the RV along with other items so he was drawing more than 20 Amps of power.

The AC ran for about 15 minutes and then cut off. It was at that point he noticed the 20Amp extension cord was melting and on fire. So, the 20 Amp breaker did trip to cut power to the RV but not before a fire started from the melting cord. Luckily he was at his RV and was able to put out the fire.

Seems to me you still need to be aware of how much power you are drawing and use the proper cords in any situation where your RV has the ability to draw more Amps than your power source is providing. i.e. a) 50 Amp RV but at 30Amp power source or b) 30Amp RV but a 20 amp power source.

[switz]

Common sense is not so common any more....

[Protagonist]

Originally Posted by switz

Common sense is not so common any more....

Let's not be negative. The concept of "common sense" only applies to topics that virtually anyone and everyone is expected to have learned something about by the time they reach adulthood. Electricity, on the other hand, is a subject that is not taught to every child as they're growing up— beyond the "don't stick your finger in that light socket!" level.

Therefore, one cannot expect the concept of "common sense" to apply to the subject of electricity, unless one is holding a conversation at the local electricians' union hall.

[nomadleslie]

I really appreciate the OP asking this question!—and I equally appreciate all this feedback. I’ve had similar questions recently, but the OP phrased them better than I.

[Mollysdad]

Here's the problem with trying to explain 50 amp vs. 30 amp.
Everyone tries to make it a scientific explanation that covers every wiring job. Therefore, the explanation gets so convoluted that the person asking is more confused than before. "Phase? Do I have single phase?"
Or, one can stick to the simple answer, and I guarantee someone will point out the one in a million exceptions that make your explanation invalid. (like 240v. RV appliances)

I tend to go with, "Keep it simple, it ain't rocket surgery." Once you see the concept, the light bulb goes off. "Oh, I get it!"

[mefly2]

They make both external and internal surge protectors. The external is easy to connect, but open to theft. Do you have insurance on your AS? If so, then why would you not want a surge protector to insure that your sensitive electronics and electrical items do not get fried? ....just saying ...
We use ours without fail ...just wish it was internal. Yes to the "dog bone" as well ...

[Mollysdad]

Originally Posted by mefly2

They make both external and internal surge protectors. The external is easy to connect, but open to theft.
We use ours without fail ...just wish it was internal.

A determined thief will take anything, but I used this on my surge protector.
The cable fits in the anti-theft ring of the Progressive Surge protector. I do a couple wraps around the power post and snug it up.

[Arnoldjeff]

Originally Posted by switz

I use this 30 amp model for our 30 amp power rated 23D and their 50 amp model for our Classic with 50 amp service.

https://www.amazon.com/gp/product/B0...oop_bw_c_x_3_w

Thank you so much – I think this is exactly what I’m looking for. Just to be clear on a couple items:
1) it appears this is a 30 amp male and 30 amp female connection on this surge protector. I’m guessing I plug the male end of my airstream Power cord into the female end of the surge protector, and then plug the male end of the surge protector plug (which is a 30a male) into a dog bone that has a 50 amp plug on the end and then plug that 50 amp male on the end of the dog bone into the RV park power outlet. Is that right?
2) if so, then this unit sits outside on the ground, so I’m guessing it’s waterproof and weatherproof. Is that right?

[rjack]

You do not need to have the dog bone as there is a simple plug adaptor available generally at any RV store. It is a good idea to carry a dog bone which fits your trailer power socket and adapts to a common 2 prong plus ground connection since many state and national parks may have only the household type outlet. One never has too much water hose or extension cord.