Problems understanding 50 amp vs. 30 amp. vs. 20 amp.

[Luciano]

Maxine, my rig is rated at 30 amps. I have a converter plug that converts the 30 amps into 20 so I can plug it into the plug at my house (which I believe are 20 amp) so I can keep the batteries charged at full capacity. This I understand.

I plan on going to Baja for a few months next year. Because of possible issues with electrical surges, I bought two surge protectors. One 30 amp and one 50 amp. The most I can pull is 30 amps because that is all my rig's system can handle. Even if the campground box is 50 amps. If this is the case, was it a mistake to have purchased the 50 amp surge protector? Do I even need it?

My main electrical cable that runs from my rig to the electrical box is 30 amp rated (I'm assuming) Both ends are rated at 30 amps. (I'm assuming) The female side that I plug into the van and the male side I plug into the electrical box. If the electrical box is 50 amp and my rig is 30 amp, do I need to get a 30 amp to 50 amp convertor, or can I just safely plug in my 30 amp cable into the 50 amp box without any problems?

Are there any other converter plugs I should have or any other surge connections I should have besides what I mentioned? I want to make sure I have everything I need, in the event I run into any problems.

Thanks for the help!

P.S. I wasn't sure where to put this post. If it would be better somewhere else, please feel free to move it, or duplicate it.

[Yarome]

 

was it a mistake to have purchased the 50 amp surge protector? Do I even need it?

do I need to get a 30 amp to 50 amp convertor

Are there any other converter plugs I should have or any other surge connections I should have

 

 

Yes. You won't need it.

 

Yes. You will need an adapter (50amp to 30amp). I prefer a dogbone type, but they also sell just the plug adapters (male50/female30amp) at places like Walmart. Generally in a kit of several adapters.

 

If you have a 50/30amp and a 20/30amp adapter then you should be covered.

 

Typically, you're generally better of with a full EMS (Electrical Management System) as opposed to just a surge protector. Either a portable unit or a hardwired unit. In your van I would assume space is premium so I might recommend a portable. You can read the additional benefits of an EMS on this last link.

 

They aren't cheap, but they have a lifetime warranty and an excellent customer service record. It's a "one off" purchase that can potentially save you countless $1000's.

[GR "Scott" Cundiff]

Think in these terms: "amps" describes how much power is available for the camper to use. A 50 amp hookup doesn't "push" 50 amps into the camper, it just has UP TO 50 amps available. If you use an adapter (commonly called a "dog bone") to adapt your 30 amp plug so it can be plugged into a 50 amp outlet, your camper will still pull the same amount of power that it pulled before.

 

Some people mix up "voltage" with "amperage." Just to say it simply, "voltage" is the "push" side - and both 30 and 50 amps in a campground are the same 110 voltage. Amperage is how much power the camper can "pull."

 

Having said that, I know there's lots to be said and learned about electricity and I'm sure others will fill all that in. This information though (plus the response on the surgeguard that Yarmone entered while I was typing), is what I think you are looking for.

[Al F]

You only need the 30 surge protector and a TWO pigtails. One pigtail to plug into the 50 amp connector, the other end is a 30amp female. You also want a 20amp to 30amp pigtail. The male end is the 20amp which plugs into the shore power post and the 30 amp end is the female end where you plug your RV's power cord into.

 

Keep in mind that with the 20amp to 30amp pig tail you only have 15 or 20 amps available and you can't run your air conditioner, if you have one.

 

For surge protection I like the Progressive Surge Protector, the built in one, if you can access the electric wiring inside the van. It can't be stolen like the portable ones. Other people like Surge Guard available at Camping World and other places.

[Luciano]

 

Yes. You won't need it.

 

Yes. You will need an adapter (50amp to 30amp). I prefer a dogbone type, but they also sell just the plug adapters (male50/female30amp) at places like Walmart. Generally in a kit of several adapters.

 

If you have a 50/30amp and a 20/30amp adapter then you should be covered.

 

Typically, you're generally better of with a full EMS (Electrical Management System) as opposed to just a surge protector. Either a portable unit or a hardwired unit. In your van I would assume space is premium so I might recommend a portable. You can read the additional benefits of an EMS on this last link.

 

They aren't cheap, but they have a lifetime warranty and an excellent customer service record. It's a "one off" purchase that can potentially save you countless $1000's.

 

Thank you, Yarome and the other gentleman that answered me. I went ahead and bought the "dog bone" that was suggested. I wish I had checked the EMS system before I bought the surge protectors. It seems like a perfect companion to the adapters. I like the fact that one unit does everything. I also bought a surge protector for the 20 amp adapter because It's never crossed my mind that I could have a surge in my home, which could cause problems in Maxine. I think I'm completely covered now. Unless, we have an earthquake and Maxine gets swallowed up by a sinkhole. lol.

[oscarvan]

Keep in mind that with the 20amp to 30amp pig tail you only have 15 or 20 amps available and you can't run your air conditioner, if you have one.

 

 

Why not? Don't run any other high demand items but 15-20 amp will push an AC all day.

[Kirk W]

Why not? Don't run any other high demand items but 15-20 amp will push an AC all day.

It will if you have a good, solid voltage on that 15/20A line. Very often such lines have problems with voltage sag, where the voltage sags to low levels with increasing loads. Since an ac motor draws more current the lower the voltage falls, such conditions can cause the circuit breaker to trip in this situation. In addition, if you have any larger loads in addition to the 13a or so for the a/c unit, you can very quickly overload things. An example would be if the coach batteries were depleted and require significant recharging.

[skp51443]

In top condition a 15 amp outlet will run an air conditioner, one in not such good shape will have problems.

 

Checking the condition of both the park's socket and your plug is a good first step. Clean and tight make for good power flow and less heat issues. You can't really check the breaker or heaven forbid fuse but they are also potential failure points. Having a large conductor cable from your plug to the RV will help reduce voltage drop and heat issues so don't skimp there.

 

What I like to do is use an IR thermometer to keep an eye on things, if the breaker, socket or plug are much warmer that surrounding objects you may be heading for trouble. A setup that might be happy with high intermittent loads may well show stress under constant load.

 

We have done this and it is an aggravation to keep most everything but the AC and the charger/converter turned off AC power. Then turning of the AC unit when we do need power for some other task. Many many trips out to the park's pole when someone forgot and microwaved something or did something else that was over the breaker's limit. Still it beats sitting and sweating so it is worth getting a handle on if you anticipate the situation in your future camping plans.

[Kirk W]

Adding to what Stanley posted, you also need to keep a close eye on the voltage inside of your RV if you do this, unless you are using a line monitor device like the Surge Guard or Progressive devices. Using one of them will shut off the power if the voltage should sag too far, but if you don't have one and choose to run an air conditioner on poor voltage, the motor will overheat and over a period of time it does harm to that motor and also to some other devices. While it may not fail during the first time that you do this, operationg equipment at voltages below 108v-ac will cause damage that is cumulative and shorten the life of that equipment. The effect is rather like smoking tobacco is for lungs. It may not fail immediately, but it reduces expected life span.

[Al F]

Keep in mind that with the 20amp to 30amp pig tail you only have 15 or 20 amps available and you can't run your air conditioner, if you have one.

I made this original posting for exactly the reasons stated in the replies just made about "yes you can run the AC IF have a good connection, IF you monitor your voltage, etc, etc.

 

And I have run my air conditioner on a 20amp connection.

 

I also assume and believe that a knowledgeable individual, familiar with electricity and electrical wiring, would disregard my advice and run their AC being fully aware of the cautions given in the last few replies.

 

However far to many RV'ers, just like many homeowners, are not knowledgeable about electricity and will just use the pig tail to plug into a worn out 15amp plug and wonder why things don't work and/or why their AC compressor is damaged.

 

One more thing to keep in mind is the length of wire and the wire size coming to the 15 or 20 amp campground power post. Did the campground use large enough wire size to carry a continuous 15amp load when the wire run is 150-200 feet or possibly more to the campground power post? Many times they did not run extra heavy wire for the very long distance. Much to expensive.

 

I believe the specifications are that a 20amp outlet should have 10 gauge wire, but with a 150-200 foot wire run it probably should be 8 gauge wire if you don't want an excessive voltage drop at a continuous 15 amps. Then you have to consider that maybe the power posts are daisy chained and you have multiple power posts on the same 10 gauge wire with 2, 3 or 4 RV's all wanting to use their AC on the 20amp outlet.

[Kirk W]

However far to many RV'ers, just like many homeowners, are not knowledgeable about electricity and will just use the pig tail to plug into a worn out 15amp plug and wonder why things don't work and/or why their AC compressor is damaged.

A very good point. And just because you do this and see no harm from it, that doesn't mean that no harm was done, only that the damage is hidden and will show up at some later time. When I was still a working service tech there was an article in a trade magazine which reported on a study of emergency service calls that concluded that nearly 60% of the electrical equipment failures are caused by the cumulative effects of operating on poor quality power, usually under voltage.

[kayakbob]

The way that I think of volts vs amps is as if I had 110 pounds of water pressure , that is the volts but what size hose is it in , that is the amps .

Just because I have 110 , it is equally important to know how large the flow { hose } is !

[Yarome]

Here's how I picture it...

[Jack Mayer]

I believe the specifications are that a 20amp outlet should have 10 gauge wire, but with a 150-200 foot wire run it probably should be 8 gauge wire if you don't want an excessive voltage drop at a continuous 15 amps. Then you have to consider that maybe the power posts are daisy chained and you have multiple power posts on the same 10 gauge wire with 2, 3 or 4 RV's all wanting to use their AC on the 20amp outlet.

A 20 amp outlet is normally wired with #12. You might increase this based on voltage drop. The nominal load on that would be 16 amps continuous of a non-motor load. You always derate.

[Ray,IN]

I apologize to Luciano, this is not what you asked. I just thought it might matter to some.

 

I've never seen a 20A receptacle in a CG, they all appear to be 15A.

A 15A plug will fit a 20A receptacle, a 20A plug will NOT fit a 15A receptacle.

Breaker size determines maximum amps available, not the receptacle.

 

20A plug:

 

Yarome, your cartoon graphic is better than a thousand words! Thanks for posting the visual aid.

[Yarome]

your cartoon graphic is better than a thousand words!

 

What can I say? I'm easily entertained.

[Kirk W]

I apologize to Luciano, this is not what you asked. I just thought it might matter to some.

 

I've never seen a 20A receptacle in a CG, they all appear to be 15A.

A 15A plug will fit a 20A receptacle, a 20A plug will NOT fit a 15A receptacle.

Breaker size determines maximum amps available, not the receptacle.

 

20A plug:

 

Yarome, your cartoon graphic is better than a thousand words! Thanks for posting the visual aid.

20A

15A

[Al F]

I have seen a lot of CG's with the 20amp outlet with a 20amp CB along side the 30amp & 50amp CB

[Pat & Pete]

I have seen a lot of CG's with the 20amp outlet with a 20amp CB along side the 30amp & 50amp CB

 

Same here . And , not just a couple , either .

[Ray,IN]

I have seen a lot of CG's with the 20amp outlet with a 20amp CB along side the 30amp & 50amp CB

Apparently I stay at cheap/older CG's that only have 15A circuits.

[RangeMaggotBob]

Think in these terms: "amps" describes how much power is available for the camper to use. A 50 amp hookup doesn't "push" 50 amps into the camper, it just has UP TO 50 amps available. If you use an adapter (commonly called a "dog bone") to adapt your 30 amp plug so it can be plugged into a 50 amp outlet, your camper will still pull the same amount of power that it pulled before.

 

Some people mix up "voltage" with "amperage." Just to say it simply, "voltage" is the "push" side - and both 30 and 50 amps in a campground are the same 110 voltage. Amperage is how much power the camper can "pull."

 

Having said that, I know there's lots to be said and learned about electricity and I'm sure others will fill all that in. This information though (plus the response on the surgeguard that Yarmone entered while I was typing), is what I think you are looking for.

That's 50 amps x 2.

[Kirk W]

 

 

Some people mix up "voltage" with "amperage." Just to say it simply, "voltage" is the "push" side - and both 30 and 50 amps in a campground are the same 110 voltage. Amperage is how much power the camper can "pull."

To clarify................ Each RV has an electrical distribution box which includes a "main" circuit breaker that will limit the maximum current drawn by that RV to whatever current limitation the RV's power cord has. A 30a RV has a cord with one supply lead, one neutral lead(or return) and one ground for safety. The 50a cord has 2 hot leads called L1 & L2, each of which by design can carry up to 50a of power and is limited by the main breaker in the RV's box which then has a main that is really two circuit breakers that are mechanically tied together and each one is rated for 50a, but if either one exceeds that 50a limit it will open both legs, no matter what the second is supplying. It is also important to note that the stated voltage today is not 110 but 120V for each of the hot suppliy connections. Measuring at the power plug you should measure 120V between one hot leg and either neutral or ground and if a 50a plug it should measure 240v between the two hot pins, or close to that.

 

Amperage is not a measure of power but a volume of electricity much like gallons is with water. Electrical power is measured in watts or kilowatts(1000 watts) and is the measure of work done determined by amps times volts and that is what the power bill you pay at home is based upon. If you look at the data plate on an appliance to see what it requires, some will have a rating in volts and one in amps while others will have only one rating of watts. If you want to know what circuit can carry the current that appliance listing watts will need, just divide the listed watts by the voltage(120).

 

That's 50 amps x 2.

In theory this is true, but real world it isn't quite since in order to get that much you would have to balance all of the RV loads exactly on each leg (L1 & L2). In practical application you actually get more like 80a total available power but it would be a very rare RV that ever has overloading problems with a 50a power cord unless something is wrong in that RV. While I have tripped an individual circuit breaker in my 50a RV's power distribution panel, never have I tripped the main or the pedestal breaker, due to overloading. I did trip the pedestal breaker once due to a failing plug on our power cord.

[Jack Mayer]

All modern RV pedestals have 50/30 20 amp breakers and outlets. The 15 amp outlets in these pedestals have not been around for many years. The 20 amp will be a GFCI in almost every location. And in MANY locations, now, the 30 will be a GFCI, and sometimes even the 50. But the 50 is rare.

[Lafitte]

Hughes Autoformer

[Al F]

Hughes Autoformer

While I know what a Hughes Autoformer is and does, I don't understand what specific info you wanted to provide about the Hughes Autoformer as it relates to which reply in this topic, or to the original posting.