Can I plug my 50amp cord from my class A into a dryer outlet?

[Contributor]

I'm asking if this is safe.

The OP wanted to know if it is safe. I contend that it is. If the RV draws exceeds the trip point for the plug, a CB will trip. This is safe

I do not consider it correct as there will then be 60-amps total available instead of 30-amps. A clothes dryer is a 240 VAC outlet.

Explain to me why this is not safe.

 

[DonTom]

And the majority of towables sold are equipped for 30 amp 120 VAC service per the RVIA.

You mean the reason I am stuck here with 3,600 watts max right now is because of those idiots at the RVIA?

I need to straighten those RVIA people out! I would never let them get away with only one hot wire and neutral. Just the fact that a neutral exists proves 240 VAC is nearby.

But I guess I am way too late--unfortunately!

-Don- Crescent City, CA

 

[DonTom]

Explain to me why this is not safe.

How did you read that into it?

I never said it was not safe. I only said it is a total of 60 amps not 30 and that part was incorrect, has nothing to do with safety.

But I wouldn't be surprised if @Kirk said it wasn't safe! He is the one with the hang-up about making adapters and such., not me. I do that type of stuff often. See here for one adapter I made. VERY rare. So rare I cannot buy such an adapter anywhere. I had to make my own. It is FOUR connections. The center thingy is the ground connection. Also is a center-tapped 240 VAC for two 120 VAC lines. The design for boats that I charged my electric motorcycle with at 8 KW.

Tap on the photo of my motorcycle and look at the last (4th) photo.

-Don- Crescent City, CA

 

[Contributor]

my 50amp coach

The OP has a 240 VAC 50 Amp coach with a 4 prong connection. His home has a 240 VAC 30A plug. He also has a 4 prong cable that is wired one to one to connect the coach to the house outlet. Why is it that some folks here refuse to accept that that is safe?

 

[DonTom]

His home has a 240 VAC 30A plug.

Yes, 240 VAC at 30 amps.

Or

120 VAC at 30 amps times two for a total of 60 amps as RVs use.

The drier plug is a 7,200 watt outlet.

3,600 watts each of two 120 VAC lines. Still 7,200 watts total when used at 120 VAC.

30 amps each hot to neutral (120 VAC). 30 amps across both hots (240 VAC).

Six pages for a simple "yes it is safe" answer?

That can only mean one thing. It means I am active in the thread!

-Don- Crescent City, CA

 

[DonTom]

Why is it that some folks here refuse to accept that that is safe?

So far, who in this thread said it was not safe?

I don't recall anybody, but at six pages I probably forgot a post or two.

-Don- Crescent City, CA

 

[DonTom]

If you want a good laugh read this thread:

I got my biggest laugh out of message number 70.

Perhaps I should have read that before I posted anything here in this thread!

-Don- Crescent City, CA

 

[SeilerBird]

You cannot win an argument on the Internet because everyone thinks they are an expert.

 

[Boat Bum]

Again, thanks for the lively debate, ya'll been doing what my wife and I do all the time, we call it violent agreement.

I'm sold this is safe for the way and frequency I would use it. You saw how I had to park it on the other side of our fence and that is a commercial lot; it's empty on Sunday.


BTW, it ran everything, two Dometic Penguin II High Capacity Air Conditioners with Heat Pump 15k BTU, 10cu Frigidaire residential, hot water heater, Sony surround system.

 

[xrated]

And here is the "Y", clear on the left side.

Delta-wye transformer - Wikipedia

en.wikipedia.org

Seems you and Dan Ex-Calif are talking about two different things.

-Don- Crescent City, CA

Trust me, I know what a WYE connection looks like...been doing it for a few years. My point was that Ex-Calif was referring to a WYE connection that had TWO legs. A WYE connection has THREE legs....and a neutral coming from the center of the 3 phases.

 

[Lou Schneider]

The biggest reason not to use a 3 prong 240 volt plug with neutral riding on the ground lead is what will happen if the neutral/ground fails.

The purpose of the neutral is to keep the center point of the 240 volt feed anchored at 0 volts. Without it the voltage is free to rise towards one or the other of the incoming hot lines, up to the full incoming voltage if the load is entirely on the opposite conductor. In typical cases, an open neutral conductor can introduce imbalances of 40-50 volts at the neutral point.

A seperate ground line will keep the exposed metal parts of whatever's plugged into it at ground potential. If you introduce a neutral to ground bond using a 4 to 3 wire adapter those metal parts will have voltage equal to the neutral swing on them.

And the neutral/ground doesn't have to completely fail. Any voltage loss along the neutral will directly translate into a voltage rise at the load end since the source end is (hopefully) tied to earth ground. Again, an intact and separate ground line will keep this voltage from appearing on exposed metal parts.

 

[DonTom]

was that Ex-Calif was referring to a WYE

That post was for all to see. I already realized you knew before I posted.

-Don- Crescent City, CA

 

[DonTom]

The biggest reason not to use a 3 prong 240 volt plug with neutral riding on the ground lead is what will happen if the neutral/ground fails.

But with the four-prong, you have two places that can fail instead of only one. But I think you mean both are unlikely to fail at once on the four-prong.

But the ground can still fail on either and is just as likely. So is having the neutral still connected without a ground somehow still considered safer? If so, why?

-Don- Crescent City, CA

 

[Lou Schneider]

But with the four-prong, you have two places that can fail instead of only one. But I think you mean both are unlikely to fail at once on the four-prong.

But the ground can still fail on either and is just as likely. So is having the neutral still connected without a ground somehow still considered safer? If so, why?

-Don- Crescent City, CA

Wow, you sure can nitpick! Consider the relative voltages and currents via capacitive coupling vs. a hard connection.

 

[DonTom]

You cannot win an argument on the Internet because everyone thinks they are an expert.

I see it differently. We can all learn from these debates. Those who "lose" the debate learn the most and by far. I am not sure how to define "win" in such a debate as what you call the winner, learns nothing.

-Don- Crescent City, CA

 

[Mark_K5LXP]

You cannot win an argument on the Internet because everyone thinks they are an expert.

Which really annoys those of us that actually are.

Mark B.
Albuquerque, NM

 

[DonTom]

Consider the relative voltages and currents via capacitive coupling vs. a hard connection.

So then you're saying @NY_Dutch had it correct back in message 67 and having a neutral as a ground is considered safer than no connection as I questioned in message 68.

-Don- Crescent City, CA

 

[Alan_Hepburn]

The OP has a 240 VAC 50 Amp coach with a 4 prong connection. His home has a 240 VAC 30A plug. He also has a 4 prong cable that is wired one to one to connect the coach to the house outlet. Why is it that some folks here refuse to accept that that is safe?

Close - looking at the decal posted right next to the power connection on the side of the RV you'll see that it says "120V/240V 50A" and NOT "240V 50A". Similarly homes are also 120V/240V service and not 240V service. A small distinction, but an important one: a 240V service does not require a neutral, but a 120V/240V service does.

 

[DonTom]

a 240V service does not require a neutral, but a 120V/240V service does.

But AFAIK, every 240 VAC outlet in a house has a neutral at the outlet. Drier outlets always do as they usually have a lot of 120 VAC stuff inside dryers.

-Don- Crescent City, CA

 

[Contributor]

A small distinction, but an important one: a 240V service does not require a neutral

You are wrong, all 240VAC systems require a neutral. You are failing to understand the role of the neutral in the usage of 240 VAC loads. If you have a pure 240 VAC load, no current will flow through the neutral, But, the neutral bonded to earth ground provides the 240 VAC a reference to 0 volts. If you do not have a neutral wire bonded to earth ground, the 240 VAC will be floating to very high and dangerous levels and start blowing up your home appliances. This 240 VAC neutral also protects the loads that only utilize one leg.