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Bobbo

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Posted: 04/23/21 07:54am Link  |  Quote  |  Print  |  Notify Moderator

No. The 14-50 is wired the same regardless of whether you are plugging in a 240v dryer or a 50 amp RV. It is what you plug in that determines how that power is used. Tell him to wire it just like it is for a 240v dryer.

The thing that fries all things in an RV is using a 3 pin 240v outlet (no NEUTRAL pin). The 14/50 is a 4 pin 240v outlet. The extra (NEUTRAL) pin makes all the difference.


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wnjj

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Posted: 04/23/21 08:39am Link  |  Quote  |  Print  |  Notify Moderator

The other thing that can fry stuff in a RV is a standard 4-pin 50A connection with an open neutral. That can cause half of the devices in your RV to see much higher than 120V and why many suggest installing some kind of protection system.

ScottG

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Posted: 04/23/21 09:17am Link  |  Quote  |  Print  |  Notify Moderator

Personally, I would tell him to wire a standard Nema 14-50 RANGE receptacle. If you tell him to do a drier receptacle you may get a 6-50 or something else.

Cummins12V98

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Posted: 04/23/21 11:11am Link  |  Quote  |  Print  |  Notify Moderator

ScottG wrote:

Personally, I would tell him to wire a standard Nema 14-50 RANGE receptacle. If you tell him to do a drier receptacle you may get a 6-50 or something else.


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Posted: 04/23/21 11:52am Link  |  Quote  |  Print  |  Notify Moderator

bucky wrote:

So the receptacle and how it's wired is the difference between RV friendly 50 amp 2 leg 110 and whatever RVers plug into that fries all the ac things in their unit?


What most commonly causes trouble for RVs are 30A RV outlets (which are pretty much unique to RVs; the official NEMA designation is even TT-30, where TT stands for travel trailer) wired incorrectly. A 30A RV connection is a 30A 120V connection, but the socket looks superficially similar to the 30A 240V 3 wire sockets that used to be standard for electric clothes dryers and are still in quite common use in exiting homes.

The 50A RV socket is the standard four wire 240V split phase 50A socket, as is used for electric ranges and other things. It is not unique or special, nor is it wired differently for different applications. Of course, any receptacle can be incorrectly wired and that can cause major problems, but doing so is not too likely with the 50A receptacle as it's something residential electricians do fairly frequently and it's not readily mistaken for some other part.





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Posted: 04/23/21 08:24pm Link  |  Quote  |  Print  |  Notify Moderator

wnjj wrote:

The other thing that can fry stuff in a RV is a standard 4-pin 50A connection with an open neutral. That can cause half of the devices in your RV to see much higher than 120V and why many suggest installing some kind of protection system.

Yes, an open neutral on a 50 amp rig will fry stuff. However, it doesn't fry just half of the stuff, it fries everything. Since there is no NEUTRAL, everything sees the full 240v. Fortunately, an open NEUTRAL is rare.

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Posted: 04/23/21 11:33pm Link  |  Quote  |  Print  |  Notify Moderator

Bobbo wrote:

wnjj wrote:

The other thing that can fry stuff in a RV is a standard 4-pin 50A connection with an open neutral. That can cause half of the devices in your RV to see much higher than 120V and why many suggest installing some kind of protection system.

Yes, an open neutral on a 50 amp rig will fry stuff. However, it doesn't fry just half of the stuff, it fries everything. Since there is no NEUTRAL, everything sees the full 240v. Fortunately, an open NEUTRAL is rare.


Everything doesn't see 240V, not at the same time. The 240V is split between the two legs; the one with the higher load and hence lower impedance sees proportionally more of the voltage, and the one with the lower load sees less voltage. In theory, if the legs were perfectly balanced, there would be no change in their voltage and no problems at all; indeed, in that situation, there is no neutral current, so it's effectively an open circuit anyhow. The legs are not perfectly balanced in normal cases, though, and how far out of balance they are can change rather rapidly and spectacularly if devices are damaged and become open circuits (or short circuits, followed by their circuit breaker tripping, making an open circuit).

A broken neutral is indeed very bad news. It does not, however, lead to 240V at all the outlets and loads.

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Posted: 04/24/21 07:33am Link  |  Quote  |  Print  |  Notify Moderator

DrewE wrote:

Bobbo wrote:

wnjj wrote:

The other thing that can fry stuff in a RV is a standard 4-pin 50A connection with an open neutral. That can cause half of the devices in your RV to see much higher than 120V and why many suggest installing some kind of protection system.

Yes, an open neutral on a 50 amp rig will fry stuff. However, it doesn't fry just half of the stuff, it fries everything. Since there is no NEUTRAL, everything sees the full 240v. Fortunately, an open NEUTRAL is rare.


Everything doesn't see 240V, not at the same time. The 240V is split between the two legs; the one with the higher load and hence lower impedance sees proportionally more of the voltage, and the one with the lower load sees less voltage. In theory, if the legs were perfectly balanced, there would be no change in their voltage and no problems at all; indeed, in that situation, there is no neutral current, so it's effectively an open circuit anyhow. The legs are not perfectly balanced in normal cases, though, and how far out of balance they are can change rather rapidly and spectacularly if devices are damaged and become open circuits (or short circuits, followed by their circuit breaker tripping, making an open circuit).

A broken neutral is indeed very bad news. It does not, however, lead to 240V at all the outlets and loads.

Agreed that all items don't see 240v AT THE SAME TIME. However, when leg 1 sees 240v and blows out its 120v items, they stop pulling power and leg 2 now sees the 240v. So, saying they don't see 240v AT THE SAME TIME is accurate. It is milliseconds between the two.

grizz272

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Posted: 04/24/21 03:39pm Link  |  Quote  |  Print  |  Notify Moderator

The plug came today. I now have everything I need to hook this puppy up. I had trouble getting wire nuts and the clamps that hod the cable in the junction box. I also could not find any romex staples to hold the cable to the wall. I did find some conduit clamps that will work. It will not be right but the cable will be secured to the wall. Four different stores were visited until I found everything I needed. Home improvement stores are lacking lot of general parts. There are no Lowes by me. I refuse to shop at Menards because of their mask rules. Home depot has rules but no one is enforcing them or commenting whether you have a mask or not.

MEXICOWANDERER

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Posted: 04/24/21 05:33pm Link  |  Quote  |  Print  |  Notify Moderator

All areas have wholesale electrical supply houses. All they ask is for customers to have an idea of what they are doing before they order parts.

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