What type of adapter do I need for this plug at a motorhome campground?

[johnnyS]

We took a little overnight trip and stayed at a campground. I reserved a "motor home electric plug in space." All the spaces with electricity had this type of receptacle. What type of adapter do I need for this? Is this a NEMA 10-30? Fortunately we had a enough range to make it to the supercharger without charging at the campsite.

 

[webbbcam]

From Wikipedia

NEMA TT–30[edit]

NEMA TT–30 plug and receptacle. (The center hole on the receptacle is not a contact.)​

NEMA TT–30 (TT stands for Travel Trailer) is a 30 A, 125 V recreational vehicle standard (hot-neutral-ground), also known as RV 30. It is frequently (and sometimes disastrously) confused for a NEMA 10–30. The RV receptacle is common in nearly all RV parks in the United States and Canada, and all but the largest RVs manufactured since the 1970s use this plug. The hot and neutral blades are angled at 45° from vertical and 90 degrees to each other, similar to NEMA 10 devices. The plug is slightly smaller than a NEMA 10 but larger than ordinary 5–15 plugs. The ground pin, however, is round, like those on straight-blade NEMA grounding devices. Referring to the diagram, the orientation is the same as the NEMA 5 plug and socket, with the receptacle neutral on the lower right. The appearance of this plug makes many people assume it is for 240 V, but this is a 120 V device. Adapters exist with the TT–30 plug on one side and a 5–15 or 5–20 socket on the other side. When the cord is detachable from the RV an L5–30 is usually used on the RV end of the cord.



Only 120 V. I don't know of any available adapter for this receptacle.

Sorry,

John

 

[TurboFroggy]

The maximum you could get out of this would be 16 amps @ 120V using the NEMA 5-20 adapter for your UMC:
Tesla Gear Shop NEMA 5-20

And a TT-30 to 5-20 adapter like this one:
Amazon.com : Conntek 14340 RV Pigtail Adapter RV 30 Amp Male Plug To 15/20 Amp U.S Female Connector : Rv Power Cord : Patio, Lawn Garden

 

[Cosmacelf]

Tesla's made from 2014 onwards can charge at 24A, 120v from such a receptacle. All you need is an adapter from evseadapters.com. The adapter converts it into a NEMA 14-50 which you can then plug your regular tesla 14-50 adapter into.

When using such an adapter, all you have to do is manually dial down the car charging current to 24A.

 

[ggr]

I think the big misunderstanding here is that pretty much all RV parks also support NEMA 14-50, but you have to specify that you want it. They probably looked at the car and assumed you didn't need the full power outlets.

 

[ChadS]

As ggr says, what you want is a camping site with a NEMA 14-50 outlet. Not all campgrounds have it, but it is really worth staying at those that do.

Note that most campground hosts will look at you funny if you say NEMA 14-50. A good many of them will also be confused if you ask for a 240V outlet (the 14-50 is the only type of 240V outlet you'll find at a campground, at least any I've ever seen). The RV lingo is "50 amp service".

 

[TurboFroggy]

I think the big misunderstanding here is that pretty much all RV parks also support NEMA 14-50, but you have to specify that you want it. They probably looked at the car and assumed you didn't need the full power outlets.

Good point. Also most RV parks have no idea what a TT-30 or 14-50 is, you have to ask for "50 AMP SERVICE", they understand that.

 

[FlasherZ]

I think the big misunderstanding here is that pretty much all RV parks also support NEMA 14-50, but you have to specify that you want it. They probably looked at the car and assumed you didn't need the full power outlets.

You'd be surprised - there are a lot of older campgrounds that still don't have a lot of "50 amp" service. That's what you want to tell them.

But even then, as several (including myself) have found - even 50A service may not be set up properly. I arrived with a few other owners, late at night, while raining, at a campground that told us where their 50 amp service was located. It turns out, however, that they only offered 50A / 120V service - tying the single ungrounded conductor to both line terminals of a NEMA 14-50 receptacle. This works for many RV's, who need only 120V but balance it across the two line terminals. It doesn't work for any RV or EV that requires 240V service, however, and we spent the next 2 hours in the rain trying to find a 240V receptacle - even troubleshooting the campground's electrical system. We finally found one 14-50 receptacle - near a permanent home on the site - that offered 240V, and spent the night swapping cars to get enough charge.

Bottom line: it helps to call ahead, and ask the campgrounds if they offer 50A, 240V service.

 

[Cosmacelf]

Flasher - I am getting this image of you going from one screwed up electrical situation to another, all the while bemoaning why, oh why, can't people build their electrical systems correctly? Kinda of like a wandering electrical Cassandra

 

[FlasherZ]

Flasher - I am getting this image of you going from one screwed up electrical situation to another, all the while bemoaning why, oh why, can't people build their electrical systems correctly? Kinda of like a wandering electrical Cassandra

Every time I think I've seen it all, I haven't seen it all. And it's not like I'm just a magnet for this stuff - talk to any electrician (especially residential electricians) and you'll hear much of the same.

A lot of it has to do with shortcuts and not thinking about the failure scenarios, like this next one: what happens if a neutral fails to an outbuilding? The amateur thinks "well, current won't flow and stuff just won't work". Well, not really - there are several return paths, one usually via earth through the the bonded neutral-ground and grounding electrodes (if the building has them properly installed), or another via appliances that are balanced on the other leg (creating over/under voltages that will destroy appliances). However, here's another case I've seen: imagine for a minute that there's a coax cable that runs between the buildings (common where people want TV in their workshops); each building has a cable box or TV connected to that coax, and the appliances have 3-prong plugs that ground the shield of the coax to the chassis. Boom, another instant return path for 120V loads through the braid of the RG6 or RG59 cable, which will be shared with the return current via the earth.

 

[Rocky_H]

Tesla's made from 2014 onwards can charge at 24A, 120v from such a receptacle. All you need is an adapter from evseadapters.com. The adapter converts it into a NEMA 14-50 which you can then plug your regular tesla 14-50 adapter into.

When using such an adapter, all you have to do is manually dial down the car charging current to 24A.

I'm seconding this recommendation and posting the link to it.
NEMA 14-50R to TT-30P RV Plug Adapter
Notice that they do point out how this adapter is wired a certain way so that the Tesla can accept it. If you try to buy from a camping store an adapter like this, it's not wired the same way and will not work for the Tesla to use.

 

[johnnyS]

Thank you for the replies. To explain our situation further, we live in southern California, supercharger mecca. In any direction we go there is a supercharger now. We like to go to national parks and other places where there are not a lot of people. On this trip, we used the new Mojave supercharger, then the one in Lone Pine. We camped/stayed at a campground just south of Bishop. I think this might be the nicest campground in Owens Valley. Owens Valley in the eastern side of the Sierras has lots of camps public and private. When I called in advance, they knew they had spaces with electricity, but they could not tell me anything about the service (since I could not confirm they had 50 amp 240V I was careful). When we checked in the gals in the office did not know anything their type of outlets. After checking out the situation I went back to the office. They showed me a box of used adapters and shrugged their shoulders. Most likely this is the type of situation we will encounter since we like to go fairly remote places.

Cosmacelf, we have a "vintage", or "classic" 2012 Model S. So can we use that adapter you mention, or is it only for 2014 on models? or is the 2014 just for the amperage. The adapter looks like a great solution to this situation.

 

[Cosmacelf]

Based on what I've been able to glean from the forums, it seems that older Model S can only charge at a maximum of 20A from 120v sources, instead of the 24A that you would like to charge at. Given the poor electrical infrastructure of most RV camps, that's probably just as well

So, yes, I'd recommend getting that adapter and you will be able to use it. If you do use it, please let us know if you managed to get more than 20A from it.

 

[Rocky_H]

@johnnyS, I would say there are enough campgrounds that you shouldn't even have to get into this situation again. Check with a site like Allstays | Campgrounds | RV Parks, which lists campgrounds and RV parks. They have maps of them for every state. When you bring up a map, on the right, you can filter by various amenities. One of them says "50 Amp". If you click that, it will only show the campground places that have those NEMA 14-50 outlets. It will also have a link to the website for that place, so you can check what they offer, how many spaces they have, or make a reservation for a space with a 50 amp outlet.

That's the preventative side of trying to get a place with 14-50 outlets, but it's not a bad idea to get that adapter for the TT-30 as a fallback plan anyway.

 

[TEG]

Related other thread:

NEMA TT-30

Also I think this video can be useful in understanding camp ground sockets:

 

[johnnyS]

Thanks for the advice on locating RV parks with 50 amp plugs. I checked this area and the only two that show 50 amp plugs do not allow tents. Since we stayed overnight in the tent I probably would have been at this park anyway. I will purchase one of these adapters and add it to our charging bag. I wish Tesla would include this type of information in a manual.

 

[Cosmacelf]

Well, this isn't a Tesla manual, but it has lots of useful charging info in it:

http://cosmacelf.net/Home%20Made%20Adapters.pdf

 

[NigelM]

Helpful tip when charging at RV parks:

RV owners/parks use the breakers as on/off switches; this means they often get used weekly (and even sometimes daily) as a manual switch. NEC permits this but in my experience the lever itself often becomes loose, through wear and tear, and it's not unusual for the breakers to trip for no apparent reason. When this happens it's generally soon after plug in so if you do charge at an RV outlet then hang around for 10 minutes and just watch that the breaker doesn't trip before you go to bed/dinner/whatever.

 

[FlasherZ]

RV owners/parks use the breakers as on/off switches; this means they often get used weekly (and even sometimes daily) as a manual switch. NEC permits this but in my experience the lever itself often becomes loose, through wear and tear, and it's not unusual for the breakers to trip for no apparent reason. When this happens it's generally soon after plug in so if you do charge at an RV outlet then hang around for 10 minutes and just watch that the breaker doesn't trip before you go to bed/dinner/whatever.

Yes, I've found my share of 50A breakers that have effectively become 30A breakers over time in campgrounds.

Certain breakers are listed for "switch duty" which is why you'll see "SWD" imprinted on some of them. These are intended to take daily switching, but are only rated up to 20A, so you'll only find them protecting the general purpose outlets. The big breakers (30A/50A) are not intended to be used for daily switching use, but I think the code writing panel let that ship sail long ago - adding proper 30A/50A disconnects would probably add at least 25% to the infrastructure costs of a campground, and the open-air nature of most campgrounds and low people density alleviate some of the concerns.

 

[Rocky_H]

Related other thread:

NEMA TT-30

Also I think this video can be useful in understanding camp ground sockets:

Thanks for the link to the other TT-30 thread. As to the video, interesting related to RV use, but I do want to make sure people here know that the dogbone adapter they mention that you can buy at camping stores, Wal-Mart, etc. will not work with the Model S. It is wired differently than the Model S charging cable is looking for. The 14-50 to TT-30 adapter at Evseadapters.com is specifically made to work with the Model S charging cable. I do know of an RV place near me, only one in a small town, that only has TT-30 outlets--no 14-50--so these adapters certainly do have some use. Also, it never hurts to throw in this reminder again. If you're using an adapter like that, make sure you set the amps in the car to 80% of the breaker rating you are plugging into.