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fansill · 05-14-2011, 11:35 AM

Good Afternoon All,

While we are camping once again at a campground that has 50 amp service, I got to wondering about...

I am a 50 amp coach with the big ungainly 50 amp cord. I know that when I am camping at a campground with 50 amp service...easy-peasy...just plug in with the standard 50 amp plug.

I have a converter plug also to plug in my 50 amp cord to my house service that transforms the large plug to a more manageable household plug.

I have a "pigtail" that steps down the 50 amp plug to a 30 amp plug.

My questions are:

1.Are there different plug heads for 50 amp, 30 amp, and 20 amp?

2.Do I always need to step down the cord even at my house? Or can I just use the converter plug?

3.When I am at a site that only has twenty amp service, do I use the pigtail (50 to 30) then another pigtail/plug to go from 30 to 20?

4. Can I use my existing portable 50 amp surge protector when I am using 30 or 20 amp service? And where do I position the surge protector?

5. Finally, I know that with 20 or 30 amp service, I am limited to what I can run...like only running one AC at a time, etc... but is there any other cautions that I should be made aware of?

Thanks,

Faith

DriVer · 05-14-2011, 12:03 PM

Quote:

Originally Posted by fansill

1.Are there different plug heads for 50 amp, 30 amp, and 20 amp?

faith, Yes - There are the 3 types of plugs which meet NEMA specifications. There are male and female plugs and sockets for all 3 amperage types you asked about.

Quote:

2.Do I always need to step down the cord even at my house? Or can I just use the converter plug?

Not sure what an inverter plug is but if it's a 20A charger type cord that's fine to keep your batteries top off.

Quote:

3.When I am at a site that only has twenty amp service, do I use the pigtail (50 to 30) then another pigtail/plug to go from 30 to 20?

Yes - Here's a new word for you, it's called a "dog bone" due to the plugs on both ends and the narrow cord in between. I use a 50A to 30A Bakelite plug adapter. Using a device like this offers you better protection from over heating a cheap dog bone on the 30A side which typically melts under routine power consumptions. I do use a dog bone from 30A to 20A and it's a robust unit with no melt down concerns.

Quote:

4. Can I use my existing portable 50 amp surge protector when I am using 30 or 20 amp service? And where do I position the surge protector?

Yes - Plug the surge protector into a 50A to 30A device and then step it down to 20A. Your 50A surge guard should work just fine. Connect your coach's power cord into the surge guard like you normally would.

Quote:

5. Finally, I know that with 20 or 30 amp service, I am limited to what I can run...like only running one AC at a time, etc... but is there any other cautions that I should be made aware of?

You may have an intelligent power management system. Select the power setting that you are flowing power from. I can set my down all the way to 20A if that's all I have. Using this type of system, the highest power draw loads will be shed and won't come on. They will show as being OFF on your panel. Air conditioning compressor 2, fan speed, refrigerator and water heater are my four hi draw circuits.

Remember circuits like a micro wave, hair dryer, washer dryer, coffee maker, toaster, etc will all draw a fair amount of power so you do have to manage those loads. There are charts that are available that will show you what the typical load draws are and they are cumulative. Ideally, you want to try to not exceed 80% of the available power available if possible especially when using dog bones.

paz · 05-14-2011, 01:00 PM

The 50 to 30-amp adapter is usually a dogbone, but a small plug-type adapter is available to go from 30 to 20/15-amps. Look in the RV section in the auto dept. at Walmart or check an RV dealer.

DriVer · 05-14-2011, 01:36 PM

The adapter that I spoke about is made of a hard plastic material that won't melt under severe draw conditions up to the rated amperage of the pedestal. It is made by Progressive Industries. (made in USA) I have lost all confidence in those typical black rubber adapters and dog bones that in the past in my experience have melted and have caused poor electrical contact and hi draw conditions increasing the amount of heat that impacts the rubber holding the blade.

This is my setup to go from 50A to 20A. The 30A to 20A dogbone is supplied by Camco RV and it's called a "Power Grip". When this equipment is in use, it does get warm however after several rallies and many hours of use there is no tell tale traces of over heating near the metal contacts. The Camco dog bone is made from a hi-temp thermo resistive material that does not melt.

I obtained the Progressive Industries adaptor from Dale Sumner the Mobile RV Medic. Dale lives and works out of Florida but travels the show circuit during the year. We expect that Dale will attend the National Rally at the Bethpage Camp & RV Resort and provide us with a seminar about RV Electricity. Not to be missed, this seminar is invaluable if you are wanting to know everything that you might want to know about your RV electrical system.

wa8yxm · 05-14-2011, 02:14 PM

I will take your questions one at a time:

1.Are there different plug heads for 50 amp, 30 amp, and 20 amp?

Yes, they are 100% different, there is no way to plug a 50 amp plug into a 30 or 20 amp outlet or any other combination without using an adapter of some kind,,, Usually a "Dogbone" (What you are calling a pigtail I think)

2.Do I always need to step down the cord even at my house? Or can I just use the converter plug?

If by Converter plug you mean one of those with a 50 amp outlet on one side and 15 amp plug on the other.. It works just fine. I have one, hve used it.. The only thing is you use it with an extension cord, since the weight of the 50 amp cord will pull it out of a wall outlet.

3.When I am at a site that only has twenty amp service, do I use the pigtail (50 to 30) then another pigtail/plug to go from 30 to 20?

See last answer, 20 amp site, or 20 amp outlet at house.. Same. I'd use a dogbone type (Pigtail) but that's because I have one.

4. Can I use my existing portable 50 amp surge protector when I am using 30 or 20 amp service? And where do I position the surge protector?

It will actually work better (At least one of its functions) on the lesser power, that function is spike supression, other functions work the same no matter the level of service.

5. Finally, I know that with 20 or 30 amp service, I am limited to what I can run...like only running one AC at a time, etc... but is there any other cautions that I should be made aware of?

Just watch your voltages, you need at least 105 for most stuff to work well..

Think of the big-ticket items in your rig..
Air Conditioners
Microwave
Electric water heat
Even the converter (12 volt converter) if the batteries are low.
(Batteries charged it becomes a much smaller item)

20 amp: ONE big item
30: Two
50 all you can eat.

NOTES:
30 amp plugs: Many people have plugged into what they THOUGHT was a 0 amp plug at someone's home (Even theirs) or garage.. These are NOT normally RV type plugs, So unless it is at a park check the voltage first.

Even if you have a 30 amp installed at home.. Check it, Many professional electricians will wire such a outlet WRONG.

DAN L · 05-15-2011, 01:36 AM

i would add to the above: use an appropriate gauge extension cord for your 20 amp circuit.
at least 12 awg, 10 awg would be better. an extension cord that is to small will induce a voltage drop and generate heat.

http://www.generalcable.com/NR/rdonl...Wire_Gauge.pdf

http://www.google.com/search?q=wire+...iw=854&bih=540