Can 20 amp and 30 amp be used simultaneously?

[Solo_RV_Guy]

Originally Posted by cavie

My campground is wired with a 50 amp main breakers feeding 30 amp peds.
The 50 amps are 240 volt feeds to the box. They are 60 amp 240 volt 6 circuit sub panels with no main breaker in them. In the box is a 30 amp single pole breaker and a 20 amp single breaker. 30 feeds a 30 amp RV outlet and the 20 feeds a 20 amp GFI outlet. So yes, there are indeed 240 volts L1 and L2 feeding the power box. The 30/20 adapter mentioned above does cause problems because as mentioned some RV's do not work when using the GFI circuit. I have tested this theory on my two trailers and neither wold work when plug into a GFI circuit.

That means neutral and ground were bonded somewhere after the Point of Service (in Code-speak). The GFCI is not at fault - there is a wiring discrepancy somewhere... but I think you know that already.

[Persistent]

Originally Posted by EdInArk

Thanks for all the input. Nothing's ever easy is it

We are a 30 amp rig and during cold weather we use a couple of 1500 watt heaters on low -- 700 watts I think. I have two 15 amp breakers for 120 volt outlets, so i plug one into a jack on each one. Problem is that one of us will sometimes start the microwave without remembering to turn off that heater and trip a breaker. I know some folks run an extension cord out the window to that 20 amp jack.

Thanks

The 20 amp extension cord out the window will work unless the campground branch breaker is limited to 30 amps. It is best to ask before using both 30 amp and 20 amp outlets in the same pedestal.

A heavy gage extension cord is the best practice for running a heater. Heavy looking cords may or may not be 10 gage and cheap ones have been know to fry plugs and sockets. Keep an eye on the cord when you first use it. Use your hand to test for heat at the connectors and run your hand along the cord looking for hot spots while the heater is on and heating.

[twinboat]

Originally Posted by cavie

My campground is wired with a 50 amp main breakers feeding 30 amp peds.
The 50 amps are 240 volt feeds to the box. They are 60 amp 240 volt 6 circuit sub panels with no main breaker in them. In the box is a 30 amp single pole breaker and a 20 amp single breaker. 30 feeds a 30 amp RV outlet and the 20 feeds a 20 amp GFI outlet. So yes, there are indeed 240 volts L1 and L2 feeding the power box. The 30/20 adapter mentioned above does cause problems because as mentioned some RV's do not work when using the GFI circuit. I have tested this theory on my two trailers and neither wold work when plug into a GFI circuit.

The 30 and 20 amp splitter adaptor will NEVER work with the 20 amp outlet being GFCI protected.

It even says that on the adaptor packaging.

The reason is that the neutral of both the 30 amp and 20 amp pigtails are tied to the single neutral of the 50 amp cord, inside the adaptor. In doing that, not all of the current flowing out the 20 amp outlet will flow back thru it.

THAT is a current imbalance and what trips GFCI devices.

[twinboat]

Originally Posted by Persistent

Heavy looking cords may or may not be 10 gage and cheap ones have been know to fry plugs and sockets. Keep an eye on the cord when you first use it. Use your hand to test for heat at the connectors and run your hand along the cord looking for hot spots while the heater is on and heating.

You don't need a 10 gauge cord for a 1500 watt heater.

The wiring in the RV is 14 gauge to outlets.
A 14 gauge cord out the window will be fine. A 1500 heater draws 12.5 amps on high. Less on medium or low.

[Gary RVRoamer]

I've worked in a bunch of campgrounds doing general maintenance and nearly all of the 30A pedestals I've encountered were wired for a grand total of 30A to the post. That single 30A wire served both the 20A breaker and the 30A breaker on the post, so trying to draw the full rated power from each will overload the wiring from the post back to its source. Whether that source has a big enough breaker to handle it is shear guesswork. Typically the source handles multiple sites, so might have a 50A or 100A breaker.


This question is no different than at home, where you have multiple 15A outlets on a single 15A or 20A circuit & breaker. You can plug stuff in each and every outlet, but the total capacity is still just the 15A (or 20A) of the feeder circuit. Having 4 x 15A outlets daisy chained together doesn't make the circuit any bigger.

[Dutch Star Don]

Originally Posted by Ljwt330

If the post is wired according to the "standard," with a 240vac feed, the 30 amp CB should be powered by one line and the 20 amp CB, by the other. Using two adapters, you would be able to "combine" the feed into your 50amp RV but the amperage available to your RV would be limited to 30amps for anything on that line, and 20amps for anything on the other. You would not have full 50 amp service on each line as you would if connected to a 50 amp post connection.

This question always gets into an argument of in phase and out of phase and goes on for days. The above answer is correct and has been done and is being done by many of us.

The only caveat.....if the 20 amp circuit is a GFCI protected, it won't work. The ability to do this is diminishing, as campgrounds improve their grid and meet code, a GFCI gets added and ends the ability to combine circuits.

I used my cheater box just last weekend at a campground that hasn't upgraded their power in 40 years. It had a 30 amp and 20 amp outlet. Having that extra 20 amp on a 50 amp coach, helps, you're still short 50 amps, but better than nothing.

[MtCamper]

To answer the OP, yes you can use both at the same time. It may do what you want though because of the way the park was wired to begin with. Odds are if you have a 50/30/20 outlet in the pedestal it will work just dandy. From what I've seen, a pedestal with 30/20 is unusual. Usually I it's either/or, not both.

As for the using an adapter to get 50 amps from a 30/20 pedestal, If you have followed and understood the discussion to this point, go ahead and do it. If you don't really understand the discussion, don't do it. As for those using the adaptors, IMHO just because you can doesn't mean you should. If by chance you screw something up in your coach or in the park, step up and take responsibility. Don't blame the park. Don't play the victim card.

[EdInArk]

I appreciate all the input above. It seems the definite answer is -- maybe.

One more. If it's a 50/30/20 post would one be better off possibly to use the 50 amp with a 50 to 30 adapter if also using the 20? We use a 50 to 30 adapter often anyway when I feel the 30 amp plug is too loose to trust.

[cavie]

Originally Posted by Dutch Star Don

This question always gets into an argument of in phase and out of phase and goes on for days. The above answer is correct and has been done and is being done by many of us.

The only caveat.....if the 20 amp circuit is a GFCI protected, it won't work. The ability to do this is diminishing, as campgrounds improve their grid and meet code, a GFCI gets added and ends the ability to combine circuits.

I used my cheater box just last weekend at a campground that hasn't upgraded their power in 40 years. It had a 30 amp and 20 amp outlet. Having that extra 20 amp on a 50 amp coach, helps, you're still short 50 amps, but better than nothing.

Damn! Somebody else get's it.! BUT there is another caveat. Sometimes it does. Seams to involve the quality of the GFI's.

[cavie]

Originally Posted by EdInArk

I appreciate all the input above. It seems the definite answer is -- maybe.

One more. If it's a 50/30/20 post would one be better off possibly to use the 50 amp with a 50 to 30 adapter if also using the 20? We use a 50 to 30 adapter often anyway when I feel the 30 amp plug is too loose to trust.

yep that will also SOMETIMES work

[cavie]

Originally Posted by MtCamper

To answer the OP, yes you can use both at the same time. It may do what you want though because of the way the park was wired to begin with. Odds are if you have a 50/30/20 outlet in the pedestal it will work just dandy. From what I've seen, a pedestal with 30/20 is unusual. Usually I it's either/or, not both.

As for the using an adapter to get 50 amps from a 30/20 pedestal, If you have followed and understood the discussion to this point, go ahead and do it. If you don't really understand the discussion, don't do it. As for those using the adaptors, IMHO just because you can doesn't mean you should. If by chance you screw something up in your coach or in the park, step up and take responsibility. Don't blame the park. Don't play the victim card.

Many, Many parks have 50/30/20 peds as mine does. 30/20 is very common in newer parks. It is NEC code for new campgrounds to have at least 20% of sites to be 50 amps. 70% to be 30 amps. All 15/20 outlets must be GFI protected. It is very easy to supply 50/30/20 peds.

[Busskipper]

Originally Posted by cavie

Many, Many parks have 50/30/20 as mine does. It is NEC code for new campgrounds. I do not know what year it became code.

Always nice to have an Electrician Chime in as on the Forum there is a lot of BS - or Just Wrong info.

[Gary RVRoamer]

One more. If it's a 50/30/20 post would one be better off possibly to use the 50 amp with a 50 to 30 adapter if also using the 20?

Again, no simple answer. It depends on which "leg" of the 50A was used to source the 20A power and which "leg" is used by the adapter to source the 30A power. Using the 50A outlet with an adapter increases your chances of avoiding an overload, but doesn't guarantee anything.

From what I've seen, a pedestal with 30/20 is unusual. Usually I it's either/or, not both.

Not in the eastern US, where many campgrounds are older (thus had only 30A/20A to begin with) and many RVs are 30A only. Smaller campgrounds that cater to pop-ups are another example - pop-ups may have 20A shore power only and most sites offer a 20A outlet.