Community Forums

Psneeld · 07-05-2021, 02:28 PM

Quote:

Originally Posted by KanzKran

Absolutely! With the old 3-wire non-grounded type, if you lose the neutral, the frame of the dryer or range becomes energized. Use an adapter to an RV and the whole coach becomes energized on loss of the neutral, and even if the neutral is still solid, it’s not at earth potential any more due to voltage drop in the neutral (see pic above).

Just not a good way to fly when you can do it right.

kb9tf · 07-06-2021, 08:29 AM

Here is a nice simple explanation of how to do it.

https://electricproblems.com/how-to-...0-amp-rv-plug/

paul65k · 07-06-2021, 09:14 AM

Quote:

Originally Posted by Oilburner53

There is a difference between two legs of 120v out of your house panel and those in an RV park, or shore power. Your house gets two separate legs of 120v that are different phases. When you install a 50 amp double or 2-pole breaker into a house panel it connects to the two separate phase legs creating 240 volts across the two legs of that breaker. This is what's needed for dryers, residential ovens and ranges and electric water heaters. If you plug into this by somehow adapting your shore power plug you will energize your RV breaker panel with 240 volts. NOT GOOD! This will fry TVs, refrigerators, microwaves, etc. An RV 50amp outlet is two sources of 120 volts from the same phase so you still only get 120 volts, not 240 volts. This may seem a little confusing but trust me and a few others on this thread when we say DON'T use a standard 240 volt dryer outlet. It will get very expensive!

This right here is why you should NEVER take electrical advice from a forum.^^^^^^^

RV parks are not wired with L1&L2 in the same phase….they just AREN’T…… please don’t give incorrect advice with such authority….it is just wrong [emoji2958]

bhale · 07-07-2021, 06:29 AM

Over the years I have had so many people want to argue with me about a 50 amp RV using 2 - 110 volt feeds. Not a 220 volt feed using each feed the same as a home. Many homes do NOT use 220 volt for anything. They have gas for water heater, cooking and drying cloths.

The original question should of been answered with a simple answer by a person with some basic knowledge of how electricity works. I hope all of these wrong and some dangerous posts have not resulted in someone having damage the their RV.

CRV2 · 07-07-2021, 08:14 AM

Regarding the correct terminology and 120/240 volts for everyone's awareness.

What is used in the US is either single phase or triple (3) phase electricity.

Single phase is either 120v or 240v in the U.S.

If you look at the attached picture, in the upper right is a transformer which represents what the power company provides commonly on a power pole nearby the house (or RV park). The voltage coming into the transformer is very high, often around 12,000 volts but could higher or lower, this high voltage allows for a lot of electricity current potential with much less line loss than lower voltage would allow for.

The transformer coil on the lower voltage side (what goes to a house or RV park and what an RV plugs into) has a center tap which is known as the "neutral" and is the "N" connection in the top right of the picture. This coil also has a "L1" and "L2". The L1, L2, and N are what come into almost every house.

If you check the voltage between L1 and L2 you will get ~240v, but between L1 (or L2) and the neutral you will get ~120v, but not because it is a different phase as remember this all is a single phase. The reason you can get 120v is by virtue of the center tap in the transformer. In any case, this is often called split-phase or two legs but is not a "2 phase" system. ~CA

CRV2 · 07-07-2021, 08:31 AM

I was called away, but to finish my point, in a 50 amp rv setup, the power cord connects to all three outputs of the transformer, L1, L2, and the N, this requires a dual breaker one side for L1 and the other for L2, and the N is bonded to the ground at the service entry panel (not in the RV). For a 30a RV, the power cord is connected to either L1 or L2 (not both) and the N which again is grounded (bonded) at the service entry panel. So, a 50a RV does have 240v in the RV circuit panel (when everything is wired correctly) but uses only L1 for certain breakers (circuits) and L2 for other circuits (breakers) which again when only using L1 "or" L2 to the N you have 120v.

So, a 50a RV has 2 120v legs with a potential voltage of 240v (that potential is rarely used in any RV I have seen), but the main takeaway is that you have 2x 50a 120v legs. A 30a RV uses only 1 leg, so you have 1x 30a 120v leg, and all from a single phase. ~CA

BTW, I am speaking here of the power side, also an RV power cord and most other uses includes and additional conductor, that being the ground conductor for safety reasons.