Is it bad to convert from 50 Amp to 30 Amp for an extended period of time

[nsohenick]

Hi All,

New to the group. Glad to be here. I am a part timer. My next adventure involves my hosts installing an additional outlet for me to plug my travel trailer into. It's a 30 Amp. They asked me what I will need to plug in. I told them 30 Amp. But I was thinking if they install a 50 Amp and I convert down, then they have flexibility for the next workcamper.

My fear is I might do some damage if I am converting down for 8 straight months. Is this concern valid? Would it not be much more of an expense for them to install both plugs 30/50 like campgrounds have?

Thank you in advance!
Nicole S

 

[Mark_K5LXP]

You're not "converting" anything, by adapting 50A to 30A all you're doing is bypassing part of your loads in the RV, usually a 2nd A/C unit. As far as the expense it generally holds that once you pay an electrician the difference in materials is a small percentage of the project, so at a minimum I'd at least run the 50A conductors, then whether it's 30A or 50A comes down to the plugs and service connection.

Mark B.
Albuquerque, NM

 

[SpencerPJ]

Simple answer, no.. that's a good idea. I typically always elect to plug into a 50A when available and drop it down to my 30A requirement. I feel the 50A plug generally always is in better condition that the 30A.

 

[Kirk]

My fear is I might do some damage if I am converting down for 8 straight months. Is this concern valid? Would it not be much more of an expense for them to install both plugs 30/50 like campgrounds have?

Just so that you know, my background is a career in electrical service and moe than 40 years of RV experience.

The first part of your question is about connecting your 30a RV to a 50a RV outlet. There is no danger at all to your RV as long as you use one of the 30a to 50a adapter cords that are readily available at RV stores or from Amazon.

As the picture shows there is a plug for the standard 50a RV outlet and a socket to connect to your 30a power cord. The reason for the 4 pins in the 50a cord is that it has 2 power leads but the adapter only connects your RV to 1 of them. Inside of your RV there is a circuit breaker that power from your cord must pass through before it is distributed to the onboard circuits and that circuit breaker prevents your RV from ever drawing more than the 30A that your power cord is rated for, so there is no chance of that ever happening.

As to the difference in cost to install, the wire for a 50a outlet has 4 conductors of a larger diameter than the 3 conductor wire for a 30a outlet and the outlet also has more to it so the cost of each would be greater. The labor to install them would be little if any difference. If I were to be asked by a place seeking RV volunteers to help I would by all means suggest that they install 50a service since that greatly expands their ability to attract volunteers. If they are not on too tight a budget I would also recommend that they have a power box installed like the one in the second picture, since it would easily accommodate either type of RV plug without the use of any adapters and could be supplied by the same electrical cable.

 

[Lou Schneider]

No problem at all plugging a 30 amp RV into a 50 amp outlet, even for an extend time. The voltage (pressure) is the same in either case. What is different is the maximum amperage (quantity) of electricity you can use.

A 50 amp outlet may create issues for the host if their electrical service is already marginal. It can supply up to 12,000 watts, which has to be taken into account along with the rest of the electrical loads. 12,000 watts is 1/2 of a 100 amp primary feed's capacity or 1/4 of a 200 amp service. A 30 amp outlet delivers a maximum of 3600 watts and places much less potential load on their system.

 

[DonTom]

I think it should be noted here that the difference between 30- amp and 50-amp service is not 20 amps but is a 70-amp difference.

It's 50 amps on L1 and another 50 amps on L2. That's a large difference on what an RV can run, as long as one knows which outlets to use on the heavier loads.

I don't understand why they call it "50 amp service" for RV parks, when it is 100 amps total.

It is 50 amps total ONLY when on 240 VAC, which RVs do NOT use.

They should use watts instead, IMO.

The 30 amp service is 3,600 watts.

The so-called 50 amp service is 6,000 watts twice or 12,000 watts total. More than three times what the 30 amp service can run.

Not counting the 20% below rule for added safety:

We get a total of 12KW with the so-called "50 amp service" at 240 VAC or 120 VAC.

The 30 amp service is always 3,600 watts max.

The 50 amp service is always 12,000 watts max, regardless if 120 VAC or 240 VAC.

So why don't they call it what it really is?

-Don- Lordsburg, NM

 

[Alan_Hepburn]

The biggest issue would be the installation itself: if the installer is not absolutely clear that it is a 30A 120V RV outlet they will most likely install a common 30A 240V outlet and your RV will not play nicely with that.

 

[nsohenick]

Thank you ALL for your valuable feedback. I may have to read these a few more times before it really sinks in. It looks like I will need to discuss how much they can 'share' with me before we determine what type of 'plug' to install. Then we can decide '30' vs '50'.

I'll be there to make sure the electrician understands its for a camper. The breaker box they are adding me to will have the camper parked right next to it!

Again, many thanks!

 

[NY_Dutch]

I think it should be noted here that the difference between 30- amp and 50-amp service is not 20 amps but is a 70-amp difference.

It's 50 amps on L1 and another 50 amps on L2. That's a large difference on what an RV can run, as long as one knows which outlets to use on the heavier loads.

I don't understand why they call it "50 amp service" for RV parks, when it is 100 amps total.

It is 50 amps total ONLY when on 240 VAC, which RVs do NOT use.

They should use watts instead, IMO.

The 30 amp service is 3,600 watts.

The so-called 50 amp service is 6,000 watts twice or 12,000 watts total. More than three times what the 30 amp service can run.

Not counting the 20% below rule for added safety:

We get a total of 12KW with the so-called "50 amp service" at 240 VAC or 120 VAC.

The 30 amp service is always 3,600 watts max.

The 50 amp service is always 12,000 watts max, regardless if 120 VAC or 240 VAC.

So why don't they call it what it really is?

-Don- Lordsburg, NM

The industry standard terminology for the NEMA 14-50 outlet used for RV's, kitchen ranges, and a number of other appliances and devices, is "50 amp 240/120 VAC service". Since the RVIA uses the NEC as part of their certification requirements for the RV industry, they should use the same standard.

 

[PJ Stough]

Hi All,



"...My fear is I might do some damage if I am converting down for 8 straight months. Is this concern valid? Would it not be much more of an expense for them to install both plugs 30/50 like campgrounds have?"

Thank you in advance!
Nicole S

You are not "converting down" at all. By connecting a 50Amp RV to a 30 amp receptacle all that changes is that you have less power available to use in your camper. It wont hurt anything, but you may have to adjust how much power you can use at any one time.
As others have said, with 30 amp service you will have 3600 watts of power available, whereas with a 50 amp connection you will have 12000 watts of power available.

 

[NY_Dutch]

Some of us seem to be missing the fact that the OP has a 30 amp TT, not a 50 amp using a 30 amp outlet.

 

[DonTom]

The industry standard terminology for the NEMA 14-50 outlet used for RV's, kitchen ranges, and a number of other appliances and devices, is "50 amp 240/120 VAC service".

Yes, a lot of our "standards" are stupid, IMAO.

And to use "standard" tool sizes is even more stupid (compared to metric) but we have to make it even more stupid by reducing the fractions. IOW, a half inch socket should be labeled as 64/128 and all other tools should also be in whatever over 128th. Then it would be a lot less stupid.

-Don- Lordsburg, NM (BTW this town is a dump!)

 

[NY_Dutch]

Yes, a lot of our "standards" are stupid, IMAO.

And to use "standard" tool sizes is even more stupid (compared to metric) but we have to make it even more stupid by reducing the fractions. IOW, a half inch socket should be labeled as 64/128 and all other tools should also be in whatever over 128th. Then it would be a lot less stupid.

-Don- Lordsburg, NM (BTW this town is a dump!)

I think you should take your complaints up with the NFPA, SAE, ASME, etc.

 

[DonTom]

I think you should take your complaints up with the NFPA, SAE, ASME, etc.

Yeah, imagine if I were there as part of the decision making!

I would do my best to make things clear! Then we would have 3.6KW RVs and 12KW RVs. And there would be 3.6KW service and 12KW service at RV parks.

Don't you think that is better than the 70-amp difference between the 30- and 50-amp RVs?

-Don- Lordsburg, NM

 

[NY_Dutch]

Yeah, imagine if I were there as part of the decision making!

I would do my best to make things clear! Then we would have 3.6KW RVs and 12KW RVs. And there would be 3.6KW service and 12KW service at RV parks.

Don't you think that is better than the 70-amp difference between the 30- and 50-amp RVs?

-Don- Lordsburg, NM

No, because it would not be the common nomenclature used throughout the electrical industry. RV's are no different than any other portable device, and neither is their electrical requirements.

There is not a "70 amp difference" between 30 and 50 amp RV service. The 50 amp 240/120 VAC supply is 50 amps at 240 and two 50 amp supplies at 120, not a 100 amp supply.

 

[Alaskansnowbirds]

99.95% of RVers could care less what you call it or how many amps it has. They pull into a campsite, pull their electrical cord out and plug it into the receptacle that matches the plug on the end of the cord. Then they go have a beer.

I would bet that less than half of RVers could tell you if their RV used 30 or 50 amp service if you just walked up and asked them. They don't care as long as it works.

 

[CharlesinGA]

NY_Dutch is correct, Without industry standards we would all be in a mess. Technically, the plug and receptacle are NEMA 14-50 and that is what it is. Real simple.

As already mentioned, the OP should be extremely careful and insist that any electrical pedestal installation they do is tested and shown to the OP to have the correct voltages across the proper terminals. If a 30 amp is used, BE INSISTENT THAT A VOLT METER IS USED TO SHOW YOU THAT THERE IS ONLY 120V ACROSS THE TWO BLADE TERMINAL.

The circuit breaker should look like this one...........

If you find a 30 amp breaker that looks like this, walk away, do not plug in and make them re do it correctly.

Many a "professional" "licensed" "expert" electrician has incorrectly wired a TT-30 receptacle for 240v because it looks similar to an old dryer receptacle and they don't bother to read the markings on the face of it, with the result being a RV's electrical system (especially the microwave, TV, and other electronics) being destroyed.

Charles

 

[Tom]

NY_Dutch is correct, Without industry standards we would all be in a mess. Technically, the plug and receptacle are NEMA 14-50 and that is what it is. Real simple.

As already mentioned, the OP should be extremely careful and insist that any electrical pedestal installation they do is tested and shown to the OP to have the correct voltages across the proper terminals. If a 30 amp is used, BE INSISTENT THAT A VOLT METER IS USED TO SHOW YOU THAT THERE IS ONLY 120V ACROSS THE TWO BLADE TERMINAL.


Many a "professional" "licensed" "expert" electrician has incorrectly wired a TT-30 receptacle for 240v because it looks similar to an old dryer receptacle and they don't bother to read the markings on the face of it, with the result being a RV's electrical system (especially the microwave, TV, and other electronics) being destroyed.

Charles

This diagram from our forum Resources shows how various receptacles should be wired:

https://www.rvforum.net/resources/50-amp-shore-power.104/download

When we reconfigured the boat dock at the house, I had "50A" service added. The contractor's "electrician" (I had my doubts) was eager to plug our boat in "to confirm it worked". I let him know that, if he did that before I'd checked it out, he'd be missing fingers on one (or maybe both) hands.

 

[DutchmenSport]

I installed (actually, really) 2 different 30 amp RV outlets (2 locations at my house), a few years apart, but wanted both locations. This worked fine when we had 30 amp travel trailers.

Then we purchased a 50 amp fifth wheel. I had to go through the expense again to rewire with a heavier wire to support the 50 amp RV service, plus the cost of the RV box. I ended up getting a box that had 20-30-50 amp receptacles. Hook up was real easy as the receptacle were already pre-wired.

After the fact, if I could do everything all over again, I would have installed the 20-30-50 amp box first and ended up saving the expense going through the process twice.

Now, I have the 20-30-50 amp box and the original 30 amp box also, which never gets used now.

 

[DonTom]

two 50 amp supplies at 120, not a 100 amp supply.

You're saying 50 plus 50 doesn't make 100. But it does. Just put a 50 amp load on each line.

-Don- Lordsburg, NM