You need another electrician for sure. If he doesn't know, you are asking for trouble.
How is he supposed to know if he never has hooked one up? It's really not a popular item. I owned my business for 30 years before I wired my 1st RV outlet. He would probably know when he look at the RV he was installing a receptical for.
It's not a 'probably' situation and definitive proofs are a finger stroke away.
If he can't work the internet as proofs, he needs to go back to being a wire puller.
It doesn't matter right. It doesn't matter wrong.
It matters that he doesn't know and dint know how to prove.
Don't get caught up in all the fancy terminology. It's basically two 120V supply lines installed separately at the outlet and operate independently of each other. See photo. This should be basic 101 for any electrician. I've heard the horror stories of this type "electrician" wiring a 50A service pole but does it just as if he were wiring it for a 220/240 dryer or such. The minute you plug into it...you blow your entire electrical system out. If he can read, show him this picture. It requires a 6/3 with ground cable...4 wires total.
It's not a 'probably' situation and definitive proofs are a finger stroke away.
If he can't work the internet as proofs, he needs to go back to being a wire puller.
It doesn't matter right. It doesn't matter wrong.
It matters that he doesn't know and dint know how to prove.
Great overviewfor your electrician: it's simply a RV 50amp outlet wired to your panel at a 240v double-pole 50amp breaker....
for your RV: it's 240v incoming thru your shore cord, and your RV's Main Panel will use it as needed... especially since your own RV's Main Breaker is also the exact same 240v double-pole 50amp breaker...
Do you have any 240v appliances in your RV? Probably not, so your RV's main panel will only have individual 120v breakers...
regardless of whether your RV has a 'need' for 240 volts or not doesn't come into play when you ask your electrician to install you a 50amp outlet at your home - it's a simple 50amp 240v outlet. The industry has a standard for this type of plug, and it matches exactly the mail end of your RV's shore power cable.
(Don't confuse your 50amp RV service with more common 30amp RV service, which is only 120 volts, and uses a different plug configuration, and is only 30amps of power. This is actually the one that many electricians can easily and accidentally get wrong - they wire this 30amp service as though it is for a 240v clothes dryer, which is completely incorrect.)
"North America.....'split phase electrical service'
This three-wire single phase system is common in North America for residential and light commercial applications. Circuit breaker panels typically have two hot wires, and a neutral, connected at one point to the grounded center tap of a local transformer. Single pole circuit breakers feed 120 volt circuits from one of the 120 volt busses within the panel, or two-pole circuit breakers feed 240 volt circuits from both busses. 120 V circuits are the most common, and used to power NEMA 1 and NEMA 5 outlets, and most residential and light commercial direct-wired lighting circuits. 240 V circuits are used for high-demand applications, such as air conditioners, space heaters, electric stoves, electric clothes dryers, water heaters, [edit: many RVs and Motorhomes], and electric vehicle charge points. These use NEMA 10or NEMA 14 outlets that are deliberately incompatible with the 120 V outlets.
Wiring regulations govern the application of split-phase circuits. Since the neutral (return) conductor is not protected by a fuse or circuit breaker, a neutral wire can be shared only by two circuits fed from opposite lines of the supply system. Two circuits from opposing lines may share a neutral if both breakers are connected by a bar so that both trip simultaneously ([4]NEC 210.4), this prevents 120 V from feeding across 240 V circuits."
Um that diagram shows a 220/240 dryer or electric range plug...just saying.
The important thing is the plug: you need one like in Gritz's diagram with a ground & a neutral. Some dryer and range plugs don't have the neutral so you can only get 220/240v out of the socket. With the neutral you can make two 120V "legs" (the 220/240v is just the two "legs" 90 degrees out of phase with each other).
All this bad mouthing an electrician who we have not heard from directly because a guy who doesn’t know anything about electricity uses the word “think” in a post when maybe the actual electrician correctly told him it could not be 110V like he expected? This level of wordsmithing makes no sense to me.
The electrician may have told him it had to be 240 and the poster simply used his own wording in writing to forum for help. It was not a quote.
Unless first proven wrong, I’ll give the electrician the respect anyone deserves.
All this bad mouthing an electrician who we have not heard from directly because a guy who doesn’t know anything about electricity uses the word “think” in a post when maybe the actual electrician correctly told him it could not be 110V like he expected? This level of wordsmithing makes no sense to me.
The electrician may have told him it had to be 240 and the poster simply used his own wording in writing to forum for help. It was not a quote.
Unless first proven wrong, I’ll give the electrician the respect anyone deserves.
All this bad mouthing an electrician who we have not heard from directly because a guy who doesn’t know anything about electricity uses the word “think” in a post when maybe the actual electrician correctly told him it could not be 110V like he expected? This level of wordsmithing makes no sense to me.
The electrician may have told him it had to be 240 and the poster simply used his own wording in writing to forum for help. It was not a quote.
Unless first proven wrong, I’ll give the electrician the respect anyone deserves.