30 amp / 50 amp

Coach-man wrote:

CA Traveler wrote:
Since very few RVs have 240V appliances the simple explanation is that you have 2 50A circuits for the RV which is a lot of power. Some loads on one circuit and the rest on the other circuit. And yes they are protected by a dual ganged 50A CB for safety. If you overload one 50A circuit both will trip disabling all power in the rig.

So why is it called 50A when it has 2 50A 120V capability or 100A total? The circuit description is 120/240V, 50A, 4 wire, 3 pole, 60Z. The 50A designation refers to the higher voltage (240V) and indeed 50A is the maximum a 240V appliance could draw. The plug is also a standard household plug and circuit. And some homes use this plug for their 50A ovens which use both 240V (heating element) and 120V (light, etc).

What I said, but not as elegant! The point is with a "50 amp" you have a lot more power for things in an RV, even 30 amp wired RV's should plug into 50 amp outlets with adaptors, at peak times when using AC, TV, micro wave, and hair dryer that will give them some "fudge" factor.

WHAT?

30A rig is 30A regardless of feeder circuit

50A circuit---30A circuit...both are 120V AC and are affected by same voltage droop.
If line voltage is 108V both will be at 108V regardless of AMP rating.

And yes lower voltage will result in higher amp draw but 30A rv is still limited to the 30A main breaker regardless of being plugged into 50A power pedesatal

CA Traveler wrote:
Since very few RVs have 240V appliances the simple explanation is that you have 2 50A circuits for the RV which is a lot of power. Some loads on one circuit and the rest on the other circuit. And yes they are protected by a dual ganged 50A CB for safety. If you overload one 50A circuit both will trip disabling all power in the rig.

So why is it called 50A when it has 2 50A 120V capability or 100A total? The circuit description is 120/240V, 50A, 4 wire, 3 pole, 60Z. The 50A designation refers to the higher voltage (240V) and indeed 50A is the maximum a 240V appliance could draw. The plug is also a standard household plug and circuit. And some homes use this plug for their 50A ovens which use both 240V (heating element) and 120V (light, etc).

What I said, but not as elegant! The point is with a "50 amp" you have a lot more power for things in an RV, even 30 amp wired RV's should plug into 50 amp outlets with adaptors, at peak times when using AC, TV, micro wave, and hair dryer that will give them some "fudge" factor.

Since very few RVs have 240V appliances the simple explanation is that you have 2 50A circuits for the RV which is a lot of power. Some loads on one circuit and the rest on the other circuit. And yes they are protected by a dual ganged 50A CB for safety. If you overload one 50A circuit both will trip disabling all power in the rig.

So why is it called 50A when it has 2 50A 120V capability or 100A total? The circuit description is 120/240V, 50A, 4 wire, 3 pole, 60Z. The 50A designation refers to the higher voltage (240V) and indeed 50A is the maximum a 240V appliance could draw. The plug is also a standard household plug and circuit. And some homes use this plug for their 50A ovens which use both 240V (heating element) and 120V (light, etc).

Coach-man wrote:

spud1957 wrote:

Coach-man wrote:
Not sure if covered, or covered well! 30 amp vs 50 amp? It is just 20 amps difference what is the big deal?? Well, the problem is it is a misnomer, you see 50 amp service is NOT 50 amps! 50 amp is two 120 volt 50 amp feeds or 100 amps total, where as 30 amp service is only 30 amps! Go with the 50 amp service, only downside is some state and Federal parks only offer 30 amps. You can use a dogbone adaptor to plug in to a 30 amp service, but you will only have 30 amps to use, so where are you going to camp? You mentioned an upgrade to a 15K air unit, that will draw around 14 amps while running, maybe up to 20 amps on start up which leaves 10 - 15 amps for other "stuuf" which depending on what you are doing may leave you short with only a 30 amp connection. If you camp anywhere in the south, I would also recomend the second AC unit which should provide enough COOL for your rig. Good luck

No you do not have 100A. You have 50A protecting two 110V legs. These are the breakers used for 50A 120/240V circuits.

Yes those are the two 50 Amp circuit breakers for a 50 amp RV outlet! You did not post the single 30 Amp circuit breaker for 30 amp service. Now granted they are tied together so niether leg can draw more than 50 Amp's, but each leg can draw upto 50 amps, (2 x 50 = 100)! If you are talking about 220 volts you are 100% correct you can not draw more than 50 amps across the two legs, but an RV is always 120 volts.

You can still only draw 50 amps on either leg period on either c/b. They are in fact the same and operate the same. Period.

spud1957 wrote:

rskeans wrote:
I think we are bickering on terminology. Each leg can draw up to 50A each. If either leg draws more than 50A then the whole system shuts down.

True. Doesn't really matter what our feed is, we are all limited to our AMP rating of our converter anyway.

What??? My PD9280 converter is rated to output up to 80 amps of 12 VDC. The converter rating has nothing to do with the shore power supply to the RV.

Rusty

rskeans wrote:
I think we are bickering on terminology. Each leg can draw up to 50A each. If either leg draws more than 50A then the whole system shuts down.

True. Doesn't really matter what our feed is, we are all limited to our AMP rating of our converter anyway.

I think we are bickering on terminology. Each leg can draw up to 50A each. If either leg draws more than 50A then the whole system shuts down.

Each breaker can THEORETICALLY handle 50 amps, so total ampacity on L1 + L2 legs is a THEORETICAL 100 amps. Actual trip point of the breaker will depend on a number of factors (accuracy of calibration of thermal element in breaker, ambient temperature, etc.) just as it does on a single 30 amp breaker.

THEORETICAL power available on 50 amp service is 120 VAC x 50 amps/leg x 2 legs = 12,000 watts versus 30 amp service with 120 VAC x 30 amps/leg x 1 leg = 3,600 watts.

Rusty

Coach-man wrote:

spud1957 wrote:

Coach-man wrote:
Not sure if covered, or covered well! 30 amp vs 50 amp? It is just 20 amps difference what is the big deal?? Well, the problem is it is a misnomer, you see 50 amp service is NOT 50 amps! 50 amp is two 120 volt 50 amp feeds or 100 amps total, where as 30 amp service is only 30 amps! Go with the 50 amp service, only downside is some state and Federal parks only offer 30 amps. You can use a dogbone adaptor to plug in to a 30 amp service, but you will only have 30 amps to use, so where are you going to camp? You mentioned an upgrade to a 15K air unit, that will draw around 14 amps while running, maybe up to 20 amps on start up which leaves 10 - 15 amps for other "stuuf" which depending on what you are doing may leave you short with only a 30 amp connection. If you camp anywhere in the south, I would also recomend the second AC unit which should provide enough COOL for your rig. Good luck

No you do not have 100A. You have 50A protecting two 110V legs. These are the breakers used for 50A 120/240V circuits.

Yes those are the two 50 Amp circuit breakers for a 50 amp RV outlet! You did not post the single 30 Amp circuit breaker for 30 amp service. Now granted they are tied together so niether leg can draw more than 50 Amp's, but each leg can draw upto 50 amps, (2 x 50 = 100)! If you are talking about 220 volts you are 100% correct you can not draw more than 50 amps across the two legs, but an RV is always 120 volts.

If you think you can draw 100 amps with a 50A double pole breaker I guess I'll let you believe that. My 50A RV has a 55A converter.


The moment you trip the 50A breaker on one 110V side, it trips the other 110V leg of the breaker as well. Notice that the on/off/reset switch is connected to both sides of the breaker?

Since we are talking RVs, saying you can draw 100A using 220 is rather a moot point for this discussion.

Get dual A/C's and 50 amp service. With 50 amp service you will not have to practice any energy management techniques. You can use what you want whenever you want without concern.
While the 50 amp cord will always be heavier, all 50 amp cords are not created equal. My OEM cord was heavy and stiff. I purchased an aftermarket 50 amp cord that was much more flexible. You can also by a 30 amp cord with a 50 amp connector that will connect to RV without any adapters.
Once you get used to 50 amp RV'ing you will forget all about limited 30 amp service.