Total 50 AMPS or Across both lines?

[ivopivo]

Yes, 50A on each of the two legs. However, you only have a total capacity of 50A whether on one leg or between the two bus bar legs. If the coach draws a total of more than 50A, the pedestal breaker protecting the 50A pedestal service should trip if it's working properly.

[TurnerFam]

not correct, unless you are ONLY referring to 240v service where EVERY appliance and device is 240v

RVs typically do NOT have 240v appliances or devices, so the two 'hot legs' are simply used as two different 120v lines, to two SEPARATE power buses - therefore 100amps of usable power is CERTAINLY and COMMONLY possible - many of us certainly do especially during the hot summer 'two air conditioners at the same time' months!

[16ACE27]

Originally Posted by ivopivo

Yes, 50A on each of the two legs. However, you only have a total capacity of 50A at 240 VAC whether on one leg or between the two bus bar legs. If the coach draws a total of more than 50A at 240 VAC, the pedestal breaker protecting the 50A 240 VAC pedestal service should trip if it's working properly.

Originally Posted by TurnerFam

not correct, unless you are ONLY referring to 240v service where EVERY appliance and device is 240v

RVs typically do NOT have 240v appliances or devices, so the two 'hot legs' are simply used as two different 120v lines, to two SEPARATE power buses - therefore 100 amps at 120 VAC of usable power is CERTAINLY and COMMONLY possible - many of us certainly do especially during the hot summer 'two air conditioners at the same time' months!

My corrections - You can't talk amps and power without including voltage.

Doesn't make any sense - there is no "between the two bus bars" in a 240 VAC system with neutral. If you were to fully load one leg to 50 amps to the neutral, so 120 VAC, with nothing on the other leg, and then exceeded it, the ganged 50 amp breaker would trip. If instead, you started adding load to the other "hot" leg to neutral at 120 VAC, you could add up to 50 amps on that leg as well (since we're talking 120 VAC). At that point the neutral would be carrying 0 amps.

[Ford1]

Originally Posted by Trkyte@msn.com

I have to question the 62 cycles per sec.
how many times must you set your clocks back?

First of all, I should probably assume that you are joking about the 62 cycles having any affect on the clock, but just in case someone else is confused by the comment, rest assured that unless you have an older 120 volt clock with an electric timer gearmotor, your clock will not be affected. Most clocks today convert the 120VAC to a low voltage DC which powers the timers ( usually IC's ) that create their own counters. Their counter rates are completely independent of the 120 Hertz A.C. source.

[cavie]

Originally Posted by Chance

The reason 30 Amp 120/240 Volt with ground could be a relatively easy future standard, which is NEMA 14-30R receptacle, is that with a simple and cheap adapter (already in production), existing 30A motorhomes could plug in — and 30A pedestal breaker would protect motorhome properly (limits to 30 Amps). Any new standard would require compatibility with existing motorhomes so campgrounds/industry could implement changes over time, and 14-30R would support that. New campground sections and motorhome manufacturers could supply 30A 240V for equivalent of 60 Amps, plenty for dual air conditioners without needing power management systems.

Unfortunately, 30A 120/240 Volt would not save enough capital investment over existing 50A standard to make it worth the trouble so I don’t see it happening; not unless it’s done for other reasons.

On the plus side, a 30A 120/240 Volt 14-30R connection could not only power existing 30A motorhomes, but with a different adapter supply up to 60 Amps to larger 50A motorhomes which could easily power their 2 air conditioners.

I can’t recall what was proposed years ago, but now that 50A is so common, it’s very doubtful there will be changes to RV electrical system unless it’s to increase power beyond 50A.

A combined 60 Amps would make a great middle ground between present 30A and 50A RV services, but probably not cost effective.




Sorry for thread thrift, but I assumed LDRider had already gotten his answer.

Existing 30 amp camper could not plug into a 120/240 outlet! 120 volts is 3 wire. 240 volt is 4 wire. There is only 1 hot wire in 120 volts.

You could not make an adapter that would separate the neutrals and grounds as required by code.

[OldWEB]

Originally Posted by Ford1

First of all, I should probably assume that you are joking about the 62 cycles having any affect on the clock, but just in case someone else is confused by the comment, rest assured that unless you have an older 120 volt clock with an electric timer gearmotor, your clock will not be affected. Most clocks today convert the 120VAC to a low voltage DC which powers the timers ( usually IC's ) that create their own counters. Their counter rates are completely independent of the 120 Hertz A.C. source.

Now I am confused that someone would post before checking the facts. IF a clock (most likely made in China) is connected to the power grid, it will use the frequency to time the ICs. With less parts, it is cheaper and easier to construct, remember I mentioned China. They can and may add the counter, also if it is battery operated, it HAS to have its own counter. I maintained the diesel generators on many isolated sites and it almost did not matter what digital clock there was, it needed to be reset. We would have a battery operated clock beside the plug in AC style to monitor the frequency over the long term, always.

[cavie]

Way to techie for this old boy

[Chance]

Originally Posted by cavie

Existing 30 amp camper could not plug into a 120/240 outlet! 120 volts is 3 wire. 240 volt is 4 wire. There is only 1 hot wire in 120 volts.

You could not make an adapter that would separate the neutrals and grounds as required by code.

Please explain what you mean by “separating” the grounds and neutrals? I’m talking about the same type of connection as a present 30A but with an extra 30A hot leg (L1, L2, neutral, and ground). The adapter would not use the extra leg for existing 30A RVs. I’m not following your objection.

When people connect their existing 30A to a 50A (240V typical 50A 4 wire), they just don’t use one of the two hot legs. Those adapters are used all the time already, although as I’ve said in other threads, the 50A breaker does not protect wiring from 50A pedestal to 30A main breaker at motorhome panel. That’s why I wouldn’t use one myself

However, if you had 30A version of the 50A 4-wire at campgrounds, the adapter would use L1 or L2, plus the neutral and ground for existing 120V 30A RVs.

For what it’s worth, these adapters are also already manufactured (about $20), and since pedestal breaker would be limited to 30A on both L1 and L2, wiring from pedestal to RV would be protected at 30 Amps.

[cavie]

Originally Posted by Chance

Please explain what you mean by “separating” the grounds and neutrals? I’m talking about the same type of connection as a present 30A but with an extra 30A hot leg (L1, L2, neutral, and ground). The adapter would not use the extra leg for existing 30A RVs. I’m not following your objection.

When people connect their existing 30A to a 50A (240V typical 50A 4 wire), they just don’t use one of the two hot legs. Those adapters are used all the time already, although as I’ve said in other threads, the 50A breaker does not protect wiring from 50A pedestal to 30A main breaker at motorhome panel. That’s why I wouldn’t use one myself

However, if you had 30A version of the 50A 4-wire at campgrounds, the adapter would use L1 or L2, plus the neutral and ground for existing 120V 30A RVs.

For what it’s worth, these adapters are also already manufactured (about $20), and since pedestal breaker would be limited to 30A on both L1 and L2, wiring from pedestal to RV would be protected at 30 Amps.

For what it is worth as an electrician I know exactly how the adapters work. An existing 30 amp service has 3 wires. A 240 volt service would require 4 wires. You tell me how you would plug in your 4 wire cord into a 3 wire cord and have 4 separate wires into the existing 30 amp RV. Neutrals and grounds are and must be separate. It is very obvious the 2 hots have to be separate. You would have to remodel the 30 amp RV service with a new panel with a double pole main breaker and service cord.

[Chance]

Originally Posted by cavie

For what it is worth as an electrician I know exactly how the adapters work. An existing 30 amp service has 3 wires. A 240 volt service would require 4 wires. You tell me how you would plug in your 4 wire cord into a 3 wire cord and have 4 separate wires into the existing 30 amp RV. Neutrals and grounds are and must be separate. It is very obvious the 2 hots have to be separate. You would have to remodel the 30 amp RV service with a new panel with a double pole main breaker and service cord.

Yeah, I know how adapters work too, but you’re not reading what I’m writing, but picturing the very opposite.

I’ve been referring to a 30A 120V/240V “new” standard that would bridge the capacity gap between 30A 120V and 50A 120/240V present RV electrical standards. And I’m saying it would be possible for existing 30A 120V RVs to plug into a future 30A 120/240V pedestal using an adapter (which already exist).

See picture below which may clear this up. It really doesn’t matter because it is unfortunately not going to happen anyway because economics don’t favor it enough.

Picture below from below:

http://www.myrv.us/electric/Pg/30amp_Service.htm

[cavie]

I'm gonna say this one more time and then I'm done. The new service is 30 amp 120/240 volts 4 wire. Your camper is old with the existing 30 amp 120 volt wire plug. Yes you could plug into it with an adapter but you would not get any benefit from it. You would have to use and adapter and get just 120 volts. You made it sound like the old 30 amp 120 could make use of the 240 volts. The only ones able to make use of the 240 30 amps would be new trailers. Then we would have 3 systems to explain the newbies and a bunch more adapters. Like you said. Ain't gonna happen.

[Chance]

Originally Posted by cavie

I'm gonna say this one more time and then I'm done. The new service is 30 amp 120/240 volts 4 wire. Your camper is old with the existing 30 amp 120 volt wire plug. Yes you could plug into it with an adapter but you would not get any benefit from it. You would have to use and adapter and get just 120 volts. You made it sound like the old 30 amp 120 could make use of the 240 volts. The only ones able to make use of the 240 30 amps would be new trailers. Then we would have 3 systems to explain the newbies and a bunch more adapters. Like you said. Ain't gonna happen.

What the hell? So now instead of admitting you either can’t read or were flat out wrong, you change your statement completely and “now” claim that that was what you were saying all along? Give me a break.

There is nothing wrong with making mistakes if you accept responsibility, we all make mistakes, but this kind of misleading communication to save face at expense of other person will ensure people will not want to communicate with you at all.

The point that was made was that during transition period if campgrounds updated pedestals to provide up to 60A of total capacity on a new standard, that older motorhomes could still plug in and get their 30 Amps. So the “benefit” an existing 30A RV would get is that it would get 30 Amps instead of zero.

Let’s just drop it since it’s not going to happen anyway, and I have better things to do than arguing.

[philhnj]

Have a newbie question for you - thank you in advance. Have a 2019 Hurricane 27b - 30 amp. When it’s at our home, would like to keep batteries charged and be able to use the RV (fridge, AC). Can I use regular household outlets / extension cord to bring power to the RV?

[cavie]

Originally Posted by philhnj

Have a newbie for you - thank you in advance. Have a 2019 Hurricane 27b - 30 amp. Can I use regular household outlets / extension cord to bring power to the RV?

Yes you can using a 30/20 dog bone and a 12 ga extention cord and some "Energy Management"

[philhnj]

Originally Posted by cavie

Yes you can using a 30/20 dog bone and a 12 ga extention cord and some "Energy Management"

Thank you very much.

[lwmcguire]

Originally Posted by philhnj

Have a newbie question for you - thank you in advance. Have a 2019 Hurricane 27b - 30 amp. When it’s at our home, would like to keep batteries charged and be able to use the RV (fridge, AC). Can I use regular household outlets / extension cord to bring power to the RV?

You would be wise to purchase the shortest possible 10 gauge extension cord rather than a 12 gague

Done the same for many years and got plenty of 12 gauge cord hot before purchasing the 10

[TurnerFam]

long but well drawn-out conversation about 'lectricity! Love it...

yes, master electricians and those in the trade will side with the 'what the breaker says is what you have' philosophy, but those of us in the 'real world' of RVs eventually learn to understand that '50amps' ain't the same as what electricians would explain it as. No matter how you 'say' it, an RV with a 50amp Main Panel, with only 120v single pole breakers for all it's circuits, plugging into a 50amp RV outlet, is going to have a range of up to 100amps of 'usable' 120v power, not just 20 more than a more typical 30amp RV outlet, though by the terminology we use, you would think so, at least initially.

The reason there is so much discussion on this and other RV forums is that the electrical trade doesn't differentiate between 120v and 240v power, when it comes to what the circuit is 'called'. A 30amp 120v circuit is called 30amps. A 30amp 240v circuit is called 30amps. But, they are far from the same. One is TWICE as much as the other, when it comes to the amount of 'amps' that can be drawn, over the hot leg, or legs, of power.

Now, while a very few large motorhomes and fifth-wheels may make use of 240v power, which is allowed by the design of their Main Panels, the vast, vast majority of 50amp RVs, whether travel trailers, fifth-wheels, or motorhomes, DON'T have any appliance or need for any usage of 240v power, so their Main Panel design does NOT allow for placement of any double-pole 240v breakers, other than the 50amp Main Breaker itself. You can't 'add' a 240v breaker, even if you wanted to. You would have to replace the Main Panel itself.
As this is the case with most 50amp RVs, it's therefore safe to say that they can use up to 50amps of power on both 'sides', or 100amps all together. Since neither side can use more than 50amps at 120v before it's side of the Main Breaker would trip, the factories try to 'even out' the circuits on each 'side' - a front a/c unit on the left, the rear a/c unit on the right, etc. It's not a PERFECT science, but they try to do this the best they can in order for the owner to be able to make use of almost ALL of that 100amps before one side exceeds the 50amps for it, and trips both sides of the Main Breaker - but, usually a single breaker actually trips before the Main breakers do.
Single breakers are the same - the factories try to squeeze in as many separate breakers as feasible, and economical for the situation, but inevitably a breaker can only do so much, even if 6 outlets are the only items on it's circuit, but are all in use by devices drawing more than the 15amps it is designed for.

Enjoy ! Fun!

[cavie]

What you all tell the newbies is 100 amps of power. But when one leg goes over 50 amps and trips the breaker they stand back and say What the hell. IF you want to use the terms 100 amps of power( witch an electrician will never say) at least have the decency to explain that it will trip with over 50 amps on one leg. If a newbie decides to move wires around in the panel and puts too much load on one leg that is exactly what will happen. You need to tell them how to balance a panel! They also need to know that there is 240 volts present in that panel. Not just 2 120 volt legs.

[Hooligan2]

Might help- A 50 amp service uses 2 50 amp breakers but they are mechanically connected together so that if one circuit exceeds 50 amps it will trip it's breaker and also the other breaker it is paired with

[cavie]