Plugging into the electric dryer outlet

[bisgaard]

It's been a while since I last asked a question on this forum & I did try to see if the topic had been covered through lots of searches, but nothing turned up.

As electric cars gain in popularity, I've noticed that Tesla & others use the traditional NEMA 14-50R socket (we usual see as our 50A service) for their charge stations. With that, there's also been a lots of 10-30P to 14-50R adapters showing up on the market (a 30A 240V pre-1996 clothes dryer to 50A RV adapter).

I'm looking to see if anyone has experience with these adapters & what lessons learned are?

... TJ

[tropical36]

bisgaard wrote:
It's been a while since I last asked a question on this forum & I did try to see if the topic had been covered through lots of searches, but nothing turned up.

As electric cars gain in popularity, I've noticed that Tesla & others use the traditional NEMA 14-50R socket (we usual see as our 50A service) for their charge stations. With that, there's also been a lots of 10-30P to 14-50R adapters showing up on the market (a 30A 240V pre-1996 clothes dryer to 50A RV adapter).

I'm looking to see if anyone has experience with these adapters & what lessons learned are?

... TJ

May be good for Tesla and others but you wouldn't be able to derive a neutral return from this conversion and one that is mandatory for an RV.

[tropical36]

Effy wrote:
Isn't a dryer outlet wired on both legs? If so you do not want to plug in your rv. You'll fry stuff fast.

You can wire the thing, any which way, you'd like.
Where the problem came in, was with people hiring professional residential electricians who wired the similar looking 30amp/120vac RV outlets for 240vac.
As for an old style genuine dryer outlet install, that would have been a blessing in disguise, cuz then the unsuspecting consumer wouldn't have been able to plug in to it. There's a slight difference in the ground pin that shouldn't allow it to fit.

[bisgaard]

Thanks all, some are good suggestions, others could get someone hurt.

Bottom line, I was looking to see if others had successfully adapted their 30A dryer plug for use with a motor home’s 50A connector, particularly since the electric car folk seem to have some success doing it.

I’m an old Navy tech, so yes, I understand they’d be a potential to draw 50A through a 30A circuit, plus the ground/neutral issues are also evident, and sure, there’s some the potential of getting some bum info from this site (no, I don’t want to start an electrical food fight, I don’t think folk are any less sensitive than they used to be on this site!).

I have little doubt I could assume the risk and make this combination work, but it’s not worth it. So I’ve bitten the proverbial bullet & I’m having a pro tie me in to the house panel with a dedicated 50A circuit.

Again, thanks for your input.

[time2roll]

bisgaard wrote:
It's been a while since I last asked a question on this forum & I did try to see if the topic had been covered through lots of searches, but nothing turned up.

As electric cars gain in popularity, I've noticed that Tesla & others use the traditional NEMA 14-50R socket (we usual see as our 50A service) for their charge stations. With that, there's also been a lots of 10-30P to 14-50R adapters showing up on the market (a 30A 240V pre-1996 clothes dryer to 50A RV adapter).

I'm looking to see if anyone has experience with these adapters & what lessons learned are?

... TJ

what exactly are you trying to do?

BTW 10-30 to 14-50 cannot meet code. Works for an EV with no neutral but not to be used on a 50 amp RV.

[hohenwald48]

This thread, as with most electrical threads on RV forums, is fraught with danger and mis-information. If you're able to differentiate between the valid information and the invalid information then you wouldn't need to ask the question in the first place. Call an electrician and do it right. Get somebody who knows about neutral sizing and ground/neutral bonding. At least somebody with a little knowledge and respect for the NEC.

I love the "ground and neutral are bonded at the panel so you can bond them anywhere else you want" comments. And remember, just because something works doesn't mean you should do it. I mean running a separate ground wire and sticking into the ground hole of a different 15A outlet is just down right wrong. :h

[Ivylog]

I made an adapter to use my brother's 10-30 outlet but I added a fourth long ground wire that I plugged into the normal 15A outlet near by to get the ground missing in the 10-30 outlet.

[DrewE]

theoldwizard1 wrote:

RoyB wrote:
Here is a neat photo marked up to shows the comparison...

No~Shock~Zone

Learn something new every day ! Well, in this case, something OLD ! I never knew there were 2 different versions ! Both of those plugs/outlets are "deprecated" and have not been used in new construction in several years.

Those are not both dryer outlets. The one on the left is a standard 30A RV outlet (NEMA TT-30), used exclusively for RVs. The one on the right is the old standard dryer outlet (NEMA 10-30) where the neutral serves as the chassis ground. The neutral wire for it should be full-sized, the same as the two hot wires. The 10-50 connection is an old standard for electric ranges that similarly has a neutral but no separate safety ground. Both of these are not permitted in new construction, but are not at all uncommon in existing houses...including DrewE's house.

The adapter for an RV (or whatever) would simply bridge the neutral connection to both the neutral and ground positions on the 50A connection (a NEMA 14-50). It would function fine, though of course the current on either leg would be limited to 30A by the 30A circuit feeding the dryer outlet. Should the neutral line fail, the chassis of the RV (or dryer) would not grounded and would float to potentially dangerous voltages depending on the relative loading of the two legs. You'd also have the usual wild voltages due to imbalances that you typically get with a broken neutral on a 120/240V circuit, so it would be a bad day all around.

The dryer outlet should also not be confused with a NEMA 6-30 (which looks quite different, with two horizontal blades lined up with each other and a U-shaped ground pin) which is a "pure" 240V plus safety ground connection that has no neutral. It is used for things like large air conditioners and 240V power tools. I think there under some circumstances the safety ground is permitted to be undersized as it is not normally a current carrying conductor.

[theoldwizard1]

RoyB wrote:
Here is a neat photo marked up to shows the comparison...

No~Shock~Zone

Learn something new every day ! Well, in this case, something OLD ! I never knew there were 2 different versions ! Both of those plugs/outlets are "deprecated" and have not been used in new construction in several years.

[John___Angela]

We have used dryer plugs, stove plugs, 20 amp 240, 15 and 20 amp 120 on our juice box EVSE for both our electric vehicles. We have a kit in our car with every imaginable adapter so we can charge in a variety of situations. This will be less necessary in the future as the buildout of charging infrastructure continues but it's handy for the time beeing.

I wouldn't use any of them on the RV though.

The picture below shows two EVSE's hanging in our garage. The one on the left is a 15 amp 120 volt. The one on the right is a 40 amp 240 volt. You can actually see it plugged into a 50 amp RV extension cord. We take this one with us on road trips along with our bag of adaptors. Works good.

[Chris_Bryant]

Trouble is, the ground is not meant or rated to be current carrying, and on a 30 amp circuit.

[rgatijnet1]

On a 30 amp RV outlet on your stick house, you will find that back at your main electrical panel, the neutral and ground are bonded together so even tho they have two separate prongs on the outlet, they are both tied together and electrically are the same.
On the 30 amp dryer outlet, the neutral is bonded to the ground back at the main electrical panel so even tho there is not a separate ground slot, the neutral acts as the ground.

[RoyB]

Here is a neat photo marked up to shows the comparison...


NOSHOCKZONE image

Your 30A RV Unit must comform to these 30A Socket readings... Note they are the same as for a standard 15A-20A 120VAc Receptacle with the exception they are controlled by a 30A 120VAc Breaker...


NOSHOCKZONE image

There doesn't seem to be good way to use an adapter cord and come up with these required readings from the 240VAC DRYER connection shown here...

In my opinion of course...

Roy Ken

[rgatijnet1]

bisgaard wrote:
It's been a while since I last asked a question on this forum & I did try to see if the topic had been covered through lots of searches, but nothing turned up.

As electric cars gain in popularity, I've noticed that Tesla & others use the traditional NEMA 14-50R socket (we usual see as our 50A service) for their charge stations. With that, there's also been a lots of 10-30P to 14-50R adapters showing up on the market (a 30A 240V pre-1996 clothes dryer to 50A RV adapter).

I'm looking to see if anyone has experience with these adapters & what lessons learned are?

... TJ

It should work just fine using the Tesla adapter altho you will not have a full 50 amp capacity on each leg. You will only have 30 amps available.
On the stick house side of the dryer outlet, both the ground and the neutral are bonded together so when the Tesla adapter is plugged in you will still have a ground and a neutral that are connected together. The 30 amp hot leads will be split to the two hot sides of the 50 amp plug and this will be fed to your main electrical panel. In your main electrical panel in your coach, at the top of your 50 amp main circuit breaker, you will have 120 volts on each input that will be out of phase with each other. IN other words 240 volts across the two inputs. All items in your coach will work fine altho you will only have 30 amps available on each side instead of 50 amps.

[Captain_Happy]

There's two types of electric dryer receptacles. One (older version)3 wire. 2 hots, and a ground wire. The newer version is 4 wire. 2 hots, 1 neutral, and 1 ground. Do not use the 3 wire receptacle. The NEC changed the requirements for wiring of new dryer outlets probably over 10 years ago.