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RV / EV in one?

bobmane

Member
Nov 5, 2017
20
6
CA
I already have Tesla Wall Charger but wanted to add ability for visitors to plug in an RV. Wondering what outlet if any could charge an RV and also charge various EVs?
 

TEG

Teslafanatic
Aug 20, 2006
21,892
8,928
Most campgrounds use NEMA 14-50 for RVs, and TT-30 for trailers.

Instead of hard wired Tesla Wall Charger, some people just install a NEMA-14-50 and use a Tesla mobile charge connector for their car... So then you could switch uses easily. But then you are limited to 40A (or in some cases 32A) max charging rate for the Tesla.

camp-sockets.png
 

Saghost

Well-Known Member
Oct 9, 2013
8,218
7,012
Delaware
I already have Tesla Wall Charger but wanted to add ability for visitors to plug in an RV. Wondering what outlet if any could charge an RV and also charge various EVs?

NEMA 14-50 is the universal standard for big power, used by most RVs (what RV parks call "50 amp service") - and the only big power adapter included in the standard UMC kit is a 14-50. (Others are available, of course.)
 

Lasttoy

Active Member
Mar 24, 2017
1,616
852
St Augustine, Fl
No. A 50 amp rv recpticle is 2 110v circuits technically. Class A RV have the systems split in half. Front ac is on one circuit, rear ac is on other half. There are 2 different 110v breakers inside. A friend of mine plugged their RV in a regular 14.50 and burnt up the entire electrical on RV. Be very careful how you wire them. I have a 50 amp classA and 30 amp class C plugs on one side of house. A 50 amp 14.50 on other side for Tesla.
Download the diagrams before you wire them.
 
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Saghost

Well-Known Member
Oct 9, 2013
8,218
7,012
Delaware
"TT-30 for trailers"
What do you mean "trailers" and what is TT-30?

TT-30 is an unusual older standard. 30A at 120V, the odd three pronged angled plug in the second post. The TT stood for travel trailer I believe - it was mostly used for camping trailers AFAIK. You can charge a Tesla with one at up to about 20A, but it's still pretty slow.
 
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Saghost

Well-Known Member
Oct 9, 2013
8,218
7,012
Delaware
No. A 50 amp rv recpticle is 2 110v circuits technically. Class A RV have the systems split in half. Front ac is on one circuit, rear ac is on other half. There are 2 different 110v breakers inside. A friend of mine plugged their RV in a regular 14.50 and burnt up the entire electrical on RV. Be very careful how you wire them. I have a 50 amp classA and 30 amp class C plugs on one side of house. A 50 amp 14.50 on other side for Tesla.
Download the diagrams before you wire them.

Either the RV wasn't complying with the standard or the outlet he plugged into wasn't. 14-50 is 14-50, and all RVs and EVs should be able to use the same outlets.

The "2 110V circuits" you're talking about are by taking the Line 1 and Line 2 sides of the 14-50 and running things between each of them and ground. An EV gets the full power by running from L1 to L2.

You do have to be careful about adapters going to 14-50, though - there are TT-30 to 14-50 adapters for RVs that won't work for an EV, because they connect both the L1 and the L2 legs of the 14-50 side to the single Line input of the TT-30. That's fine for those RVs that don't have 240V devices, but means the EV will get no power from it.
 

bobmane

Member
Nov 5, 2017
20
6
CA
Just looked and on this pedistal all I have is 4 breaker slots on a 200 AMP meter. So I have 200 AMPS but only 4 slots. 2 slots are being used by Tesla (100 AMP) and a GFCI is using a 20 AMP. So only one slot open. I guess not possible to use a single pole 50 AMP for the RV 14-50?
Screenshot 2018-04-14 15.04.19.jpg
 

Saghost

Well-Known Member
Oct 9, 2013
8,218
7,012
Delaware
Just looked and on this pedistal all I have is 4 breaker slots on a 200 AMP meter. So I have 200 AMPS but only 4 slots. 2 slots are being used by Tesla (100 AMP) and a GFCI is using a 20 AMP. So only one slot open. I guess not possible to use a single pole 50 AMP for the RV 14-50? View attachment 294296

Can't to 240V with a single breaker, because you have two hot lines involved. Need a new box...
 

bobmane

Member
Nov 5, 2017
20
6
CA
Would it be possible to run
50a breaker to Tesla
20a breaker to GFCI outlet
50a breaker to NEMA 14-50 for RV / EV
30a breaker to TT-30 for older travel trailers
on a 100A feed to a 100A panel?
(i have a 100 amp panel with tons of slots)
 

Blup85

Member
Oct 26, 2016
801
674
Chico
Just looked and on this pedistal all I have is 4 breaker slots on a 200 AMP meter. So I have 200 AMPS but only 4 slots. 2 slots are being used by Tesla (100 AMP) and a GFCI is using a 20 AMP. So only one slot open. I guess not possible to use a single pole 50 AMP for the RV 14-50? View attachment 294296
You should be able to change out to a quad breaker. 50 amp 240 and 2 20 amp (
Basically, it would require you to change out all your existing breakers except the 100
 

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TEG

Teslafanatic
Aug 20, 2006
21,892
8,928
NEMA5-15 household outlet = 120V @ 15A... One ~20A breaker...
TT-30 "Travel Trailer" campground outlet = 120V @ 30A... One ~30A breaker...
NEMA14-50 RV campground outlet = 240V @ 50A... TWO ~50A breakers...

The breaker sizing and wiring size behind the outlet can vary a bit from place to place...
Best to be conservative with your continuous (EV charging) power draw to avoid overheating the outlet or breaker.

For NEMA5-15 maybe only pull 12A max safelty ( [email protected]=1.44kW )
For TT-30 maybe only pull 20A max safely ( [email protected]=2.4kW )
For NEMA14-50 maybe only pull 40A max safely. ( [email protected]=9.6kW )
Some NEMA14-50 are wired with only wiring rated for 40A and/or installed with 40A breakers. In that case, don't plan to EV charge at more than 32A ( 7.68kW )

Tesla will charge using 240V from NEMA14-50 so needs it wired with "two hots" to get proper 240V.
Some campgrounds wire the same 120V circuit to both sides of a NEMA14-50 socket, and most RVs are only 2 sets of 120V appliances, so do OK with that.
But in those cases, you may find that Tesla charging and campgrounds doesn't provide full power capability.

"Normal" NEMA14-50 wiring:
14-50r.png

In the above, the 2 120V circuits are each half of "split phase" power, and so sum to 240V across.
If a campground runs the same non-split phase 120V to one or both sides of a 14-50 socket then you get 0 volts when trying to get current from X+Y

I think some people have concluded that their UMC was bad, a breaker must be blown or some such when it was really just a case of incompatible wiring. Campgrounds may "bend the rules" of the typical way to use that kind of socket.
 
Last edited:

TEG

Teslafanatic
Aug 20, 2006
21,892
8,928
I don't want to recommend anything. You should consult a professional electrician if you have any doubts.

I am saying that I have heard of some places that installed lower gauge wiring and/or smaller than usual circuit breakers, so you shouldn't just assume that every NEMA14-50 is good for 50 amps everywhere you go.

I think it is better if you draw the minimum current you need to get the state of charge you need in time. ( Like overnight charging can be slower. )

Trying to pull 50amps, or even 40 at campgrounds with worn old NEMA14-50s can be problematic. Better to do 32 to be safe.

There are different options on how you can do things at your own house.
 
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Webeevdrivers

Active Member
Jan 2, 2017
2,352
4,107
Canada
@TEG are you saying I can use smaller breakers or just be mindful during use and draw less?

TT30 is not an old standard. It is used by the vast majority of New RV’s of any type including trailers, fifth wheels and Motorhomes with one AC. Most dual or triple AC rv’s use 50 amp 240 service.
 

dgpcolorado

high altitude member
Apr 25, 2015
2,653
3,926
The Western Slope, Colorado
TT-30 is an unusual older standard. 30A at 120V, the odd three pronged angled plug in the second post. The TT stood for travel trailer I believe - it was mostly used for camping trailers AFAIK. You can charge a Tesla with one at up to about 20A, but it's still pretty slow.
I set my car at 24 amps when using TT-30 and it worked fine. If the outlet can't handle that current it isn't wired correctly — always a possibility, I suppose. Still rather slow charging at 2.9 kW, however.

I do use a lower current — 30 amps — when using 14-50 outlets but that's to lower the heat and wear on my UMC and speed usually isn't a concern when charging overnight at 240 V. That's what I use at home, as well as at campgrounds with "50 amp" service.

Charging on TT-30 at Zion National Park:

Model S at campsite Zion NP1680sf 6-9-16.jpg
Model S at campsite Zion NP1683sf 6-10-16.jpg
 
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Saghost

Well-Known Member
Oct 9, 2013
8,218
7,012
Delaware
I set my car at 24 amps when using TT-30 and it worked fine. If the outlet can't handle that current it isn't wired correctly — always a possibility, I suppose. Still rather slow charging at 2.9 kW, however.

I do use a lower current — 30 amps — when using 14-50 outlets but that's to lower the heat and wear on my UMC and speed usually isn't a concern when charging overnight at 240 V. That's what I use at home, as well as at campgrounds with "50 amp" service.

Charging on TT-30 at Zion National Park:

View attachment 294418
View attachment 294419

Agreed. There was a time when the cars limited 120V charging to less than the 24A a TT-30 should be capable of, but that's apparently no longer the case.
 

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