50a to 30a question

[Cloughfam]

Looking towards the future about going from a TT to a FW. One of the models I like the most comes standard with 50a service. Should that be a concern as 99% my wife and I camp where only 30a is available?

Not sure if its detrimental to the lifespan of the appliances, or if we just need to treat it like we currently do and turn off the AC if we need to run the microwave.

Thanks for any help clearing this up for me.

Mike

[Dave_H_M]

CA Traveler wrote:
The rig is designed to use more power. Multiple A/Cs, HW, MW, etc and you may want to push that additional button but can't - The 30A pedestal CB will trip.

I added an additional circuit with 2 plugs mostly for ceramic heaters. For 50A pedestal it plugs into an existing basement outlet. For 30A I run an extension cord to the pedestal (most have 30A and 20A outlets). Others have modified a AC power wires so it can be run off of the extension cord. By all means use a heavy extension cord and not the typical home cord.

If you are not aware 50A is 240/120V 4 wire. In RV speak this simply means you have two 50A 120V circuits for the rig or as some like to say 100A available vs the 30A pedestal.

Same thing i did. Now have a plug on both sides inside the fifth wheel that is wired to a 20 amp plug in socket outside for and extra extension cord to the RV. i use a 12/3 cord for that hook up.

[FLY_4_FUN]

Knowing that 99% of the campgrounds we visit are 15 and 30A I opted to buy a new marinco cord that threads onto the 50A plug on the rig, and terminates with a 30A bone. No heavy adapters to haul and just the 15A end plug if ever needed. My 50A cord has never left its packaging from the dealership and I don't miss trying to lug it around. Worth considering.



Daryll

[CA_Traveler]

Fisher Bill wrote:
This explains why I have a dead set of outlets while shored up at home with a wimpy 15A to keep things running while we're remodeling the kitchen, missing that second leg from the service...

And I wouldn't even think of using the AC but we can get a bag of popcorn out of the microwave at least.

With a 20/50 adapter(s) you should have power on both 50A hot legs. You have some other problem.

[Fisher_Bill]

This explains why I have a dead set of outlets while shored up at home with a wimpy 15A to keep things running while we're remodeling the kitchen, missing that second leg from the service...

And I wouldn't even think of using the AC but we can get a bag of popcorn out of the microwave at least.

[CA_Traveler]

nayther wrote:
so if I am plugged into a 30 amp, using a dogbone adapter to connect my 50 amp RV can I still use a 50 amp surge/power protector even though only one leg of the 120 is hot?

Yes

Both legs are hot as the 30/50 adapter connects both 50A legs together - otherwise you would only have power to half the rig. And the EMS units do not fault when you don't have 240V.

[nayther]

so if I am plugged into a 30 amp, using a dogbone adapter to connect my 50 amp RV can I still use a 50 amp surge/power protector even though only one leg of the 120 is hot?

[Cloughfam]

Thank you all for the input. I sincerely appreciate it!

[BB_TX]

Going deeper. If you lost the neutral wire, then the devices connected to H1 and the devices connected to H2 would effectively be wired in series. As such, if the impedance of the devices on H1 was EXACTLY the same as the impedance of the devices on H2, there would be no damage to the devices on loss of neutral. In such a case, there would be no flow thru neutral even if the connection was intact. A basic voltage divider splitting the voltage of 120 vac to each side.

Now, if the impedance of the devices on H1 was twice the impedence of the devices on H2, then H1 would be hit with 160 vac and H2 would only get 80 vac. Of course 160 vac is enough to fry 120 vac rated devices.

You would not get the full 240 vac on any devices on loss of neutral unless the total impedence on one hot leg or the other was zero, or essentially a dead short.

:B

[CA_Traveler]

Also the secondary winding on the transformer is single phase as a single secondary center taped winding can only be one phase.

Split phase is a more descriptive and accurate term. But yes many incorrectly refer to it as out of phase.

[CA_Traveler]

BTW The center tap on the 240V utility secondary winding is the neutral and it keeps 120V on the two unbalanced hot leads. When it's open then you'll get 240 on the 120 to their now open neutral. That lets the smoke out.

[CA_Traveler]

centerline wrote:

Me Again wrote:
You still should install a 50 surge protector.

While on a 50 amp outlet, if you loose neutral you burn up all your AC items with 240V across them.

I agree strongly with using a surge protector (with combined auto transfer switch if you have a hardwired generator onboard)....
BUT.. as for burning up all the ac appliances if the neutral leg should be lost for some reason, I dont see how this is even possible unless its wired incorrectly INSIDE the RV...

the 50a shore power has the potential of supplying 240volt power to the unit, but the power panel INSIDE the rv is where the 120v would have to be combined to create the 240v power. this is not the case on most RV's... but the high end units with a washer/dryer option or household range will have the 220v option inside (or anyone who knows what to do could wire a circuit in)

bottom line is, on a 50a circuit, there are 2 separate legs of 120v power that are "out-of-phase" with one another coming in to the rv (if the 2 legs of 120v power were "in-phase" with one another, like on a generator, there would no option for 240v power), and these are NOT combined in any manner except at the 240v appliance itself... and in the USA the neutral is only acting like a ground in 240v circuit, and without it the appliance still works like normal. but ALL the 120v circuits will be lacking power (because half of its circuit has been lost).. but the appliances will be fine.

some countries of the world use only 2 wires to supply their 240v power, and not the three that we use here in the US..

but yes, one CAN absolutely fry all their 120 volt components if they dont know electricity, and yet try to do their own wiring inside the RV distribution panel or on the shore power side of it...

Sorry but just about everything you posted in incorrect.

A 50A open neutral will cause first 240 on one hot leg in the rig and then the other. Most electrical appliances turned on or in standby will or could let the smoke out. Absolutely nothing to do with incorrect RV wiring.

And BTW some generators like mine are 120/240V.

[centerline]

Me Again wrote:
You still should install a 50 surge protector.

While on a 50 amp outlet, if you loose neutral you burn up all your AC items with 240V across them.

I agree strongly with using a surge protector (with combined auto transfer switch if you have a hardwired generator onboard)....
BUT.. as for burning up all the ac appliances if the neutral leg should be lost for some reason, I dont see how this is even possible unless its wired incorrectly INSIDE the RV...

the 50a shore power has the potential of supplying 240volt power to the unit, but the power panel INSIDE the rv is where the 120v would have to be combined to create the 240v power. this is not the case on most RV's... but the high end units with a washer/dryer option or household range will have the 220v option inside (or anyone who knows what to do could wire a circuit in)

bottom line is, on a 50a circuit, there are 2 separate legs of 120v power that are "out-of-phase" with one another coming in to the rv (if the 2 legs of 120v power were "in-phase" with one another, like on a generator, there would no option for 240v power), and these are NOT combined in any manner except at the 240v appliance itself... and in the USA the neutral is only acting like a ground in 240v circuit, and without it the appliance still works like normal. but ALL the 120v circuits will be lacking power (because half of its circuit has been lost).. but the appliances will be fine.

some countries of the world use only 2 wires to supply their 240v power, and not the three that we use here in the US..

but yes, one CAN absolutely fry all their 120 volt components if they dont know electricity, and yet try to do their own wiring inside the RV distribution panel or on the shore power side of it...

[Michelle_S]

We have even survived on 20 amps when traveling in semi-remote areas such as The Yukon and Newfoundland. Just have to be aware of current draw and watch what you turn on.

[Samsonsworld]

I only run one a/c and bring a floor fan to help stay cool in the summer. Other than that, no noticeable difference.