2018 tab 400 is it safe to use 50 amp service with an adapter?

cowboypete

I am planning my trip and one of the sites I really want to stay at only has 50 amp service.  Can I SAFELY use A 30 amp/50 amp adapter??  My mind says no, but I would like someone more experienced than me to say Yes or No.   Thanks, Bob

N7SHG_Ham

It will be fine. I also suspect they just didn't list the 30 and 15/20 power options, it is rare to not have those in the box with the 50a plug.

Sharon_is_SAM

Yes.  The 30 amp will only use one leg of the 50 amp.  No problem.
https://www.etrailer.com/faq-30-amp-50-amp-rv-service-adapters.aspx

AnOldUR

The potential problem is that if you don’t include over current protection after the adapter your 30 amp wire leading to your RV is not properly protected by the 50 amp breaker.

Sharon_is_SAM

So, just plug in the surge protector into the adapter.

Dalehelman

Just never try to adapt to 50 amp at home or some place that is not designed for RVs.

ScottG

The problem is less about the amperage than it is about the voltage. 50A RV service is typically 240V, while 30A service is 120V. However, as Sharon noted, a proper 50A --> 30A RV adapter will take care of this.

Dutch061

A 50 Amp service could be either 120 or 240 VAC as shown below. The RV that I had that was a 50 Amp used the 2 x 120 VAC configuration. Either way it will not matter since you will only connect to one of the 2 x 120 VAC. In order to get 240 VAC you have to combine the 2 hot wires. In other words ALL Power Posts are wired in the 2 x 120 VAC configuration. 

Brad

ScottG

AnOldUR said:

The potential problem is that if you don’t include over current protection after the adapter your 30 amp wire leading to your RV is not properly protected by the 50 amp breaker.

This would only be a problem if the T@B tried to draw more than 30A of current. If this happened, the T@B's main breaker would trip.

In short, the amount of current (amps) flowing is determined by the device in use, not the maximum capacity of the service.

AnOldUR

I’m not going to argue with your logic (I agree with it) and I’m not an electrician, but I’d bet that there’s a code violation if no overload protection is used before the power cord. Good chance I’d lose that bet.  

Dutch061

The thing to remember is 50 Amp has 2 x 120 VAC that is on a Dual Pole Breaker, which means that each 120 VAC is on 50 Amps. However, the 30 Amp Single Pole Breaker in the camper will provide the proper protection for everything inside. 

Brad

AnOldUR

@Dutch061 Nope. Each leg is 50 amps.

edit: It'll take a 50 amp load on either of the legs to trip the breaker, but both legs will be tripped if one side sees the overload.

Dutch061

@AnOldUR, Ah yes I stand corrected and will adjust my previous post. Can't blame it on coffee at the time of day I made that post.

Brad

cowboypete

Thanks everybody for excellent advice.  And I always use a  high quality surge protector.  Bob

ScottG

AnOldUR said:

I’m not going to argue with your logic (I agree with it) and I’m not an electrician, but I’d bet that there’s a code violation if no overload protection is used before the power cord. Good chance I’d lose that bet.  

Consider that almost every household electric device has a power cord of 16g or smaller wire, yet you still plug these into receptacles on 15 or 20 amp circuits capable of providing current greater than the capacity of the cord. However, the power cords are sized for the current requirements of the device so the smaller wires pose no hazard when used as intended.

That said, I don't know how or if the code applies to RV installations, so I won't take your bet since codes are often based on obscure "what if" circumstances. Regardless, under normal use your RV cord should be fully protected by the T@B's main 30A breaker.

@cowboypete, a power surge is not the same as an overcurrent condition. A power surge is a transient spike in voltage that originates on the grid/pedestal side, while an overcurrent is excessive amperage demand that originates on the camper side. While RV surge protectors and EMS devices probably also incorporate overcurrent protection, I would not assume that one necessarily protects you from the other.  

AnOldUR

ScottG said: Consider that almost every household electric device has a power cord of 16g or smaller wire, yet you still plug these into receptacles on 15 or 20 amp …

This is the same logic that I would use except for that I’ve read the code violation thing in many places but haven’t found the actual code. Here’s a quote from one of the sources:

“Because the RV’s main breaker is installed in the distribution panel of the RV, the above scenario is unlikely. Most of the time, the RV’s main breaker will pop before the 50 amp pedestal breaker does.

This scenario, however, does not fully protect your wires from becoming overloaded. If there were a short on the line or a fault in the breaker, your protection would be limited. Not to mention, even with the RV’s breaker, using a 50A/30A dogbone adapter without protection is technically an electrical code violation.”

https://mortonsonthemove.com/can-you-hook-a-30-amp-rv-to-50-amp-power/

edit to add:
This is one of those grey areas where you have to decide what level of risk you’re willing to take. Even if you have an onboard EMS, using surge/over-current protection at the breaker box is cheap insurance. And speaking of insurance, in the rare instance that there is a problem, you probably will not be covered for the damages.

ScottG

Good article, @AnOldUR. See? I told you I wouldn't take that bet!  ;-)

I like that they also emphasized the difference between surge and overcurrent protection, and the need for a device that protects against both if that is your intention.