Question about 125/250V AC power cord adapter

My Nissan Leaf Forum

Help Support My Nissan Leaf Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

dsinned

Well-known member
Joined
Jun 27, 2014
Messages
152
In order to have a way to power up my portable, universal input, EVSE from a 30A 125V receptacle in most RV Parks, (especially when a 50A 250V receptacle is unavailable), I purchased a male, 3 prong, TT-30 to female, 4 socket, TT-50, converter/adapter.

How should this be wired internally? It looks like one angled blade line side on the 125Vac source (TT-30) male end is connected to neutral and the other male angled blade side is connected to BOTH sides of the line on the load (TT-50) side. I know that the neutral wire to my EVSE is NOT connected.

Is this correct? Will this provide single phase, 125Vac power to my EVSE just like a standard household 115Vac receptacle? The only difference is the amperage rating?
 
TT-30, is a 120V circuit. It should be straightforward to wire it - what plug is on your 'universal input' EVSE? TT-30 to NEMA 5-15 (maybe NEMA 5-20) adapters should be commonplace, and fairly inexpensive. Most 'modern' EVs max out at 16A on 120V, except Tesls which can use 20A.
 
dsinned said:
I would be using this adapter with my JuiceBox. It has a NEMA 14-50P plug-in cord on the AC input. The TT-30 to TT-50 Adapter I bought on AMAZON for about $13. It's a nice quality unit, yellow in color, almost identical to this one (except for the color).

http://www.ebay.com/itm/ROUND-ADAPT...Parts_Accessories&hash=item258ece70e7&vxp=mtr

I had no idea what a "TT-50" was, but in the link above, that's a NEMA 14-50. Really an a easy way to overload a circuit, and frankly shouldn't be available, since you have the ability to pull up to 50 amps on a 30 amp circuit.
 
There should be a fuse or breaker to protect the wire. Some RV parks have the breaker right there.

This adapter should be feeding "one side" on the 240V circuit on the NEMA 14-50. You'd have to ask the JB folks how to run their NEMA 14-50 plug w a 120 V supply. Which hot do you use?
 
srl99 said:
There should be a fuse or breaker to protect the wire. Some RV parks have the breaker right there.

This adapter should be feeding "one side" on the 240V circuit on the NEMA 14-50. You'd have to ask the JB folks how to run their NEMA 14-50 plug w a 120 V supply. Which hot do you use?

Well, there is only one "Line / Phase 1" HOT, the other is Line / Phase 2.

Honestly, I can't imagine it matters for MOST cars, and MOST EVSE's (I have no idea about Juicebox), but for a Tesla powered car (Model S, Toyota Rav4 EV, and Mercedes B-Class ED), it does matter.

You must have the polarity correct, meaning 120 volts must come from Line 1 to Neutral.

The blades of a NEMA connector are identified with:

Blade Function...Letter...Color...Notes
Ground.............G.........Green
Neutral.............W.........White
Phase 1 hot.......X.........Black....X only is single phase 120 V
Phase 2 hot.......Y..........Red......X Y is single phase (centre-tap neutral) 240 V or 480 V
Phase 3 hot.......Z.........Blue......X Y Z is wye three phase 120/208 V



http://img189.imageshack.us/img189/1879/nemavariants.png" onclick="window.open(this.href);return false;
 
I found the follow post which must have originally been posted on the TESLA forum. This seems like it came from a knowledgeable source. It helps to answer my question, and it looks like with no connection to the 14-50's "neutral" at the EVSE, the adapter I have should work to provide an AC power source of 125Vac, up to 30A from a TT-30 outlet found at most RV Parks.

In this adapter, the hot at L2 on the 30-TT side is connected to the neutral on the 50-TT side, which has N/C at the JuiceBox. What I am concerned about is that the hot at L1 on the 30-TT is connected to BOTH hots on the 50-TT side. This results in the same hot side of the line being connected to both input terminals of the JB's AC relay via two parallel paths in common to the source.

This parallel connection continues on out thru the J1772 cable to the car's onboard charger. The potential from either of those wires to ground is only 120Vac, so what happens when they are connected to the input of the OBC? Would it be the same as two 120Vac sources on the same single phase being paralleled together, or only one side put under load but not the other side, or would the OBC see no potential difference across its AC input and fail to energize?

The Unofficial, Use At Your Own Risk, Blah, Blah Blah,
Model S Home Made Adapter Document

V2.3 – September 10, 2014

.
.
.
RV RECEPTACLES
If you find yourself at an RV park in the US, you’ll typically find that RVers use one of two different electrical hookups. The “50 AMP” connection is our NEMA 14-50 receptacle, so if your site has one of those, just use the Tesla 14-50 adapter and you’re good to go.

The “30 AMP” connection is a unique to the RV world, TT-30. This provides 120V at 30 amps, for a de-rated power of 2.8KW. It will take a while to charge using this (like 6 miles/hour), but if you’re stuck at the RV park for a while, it is better than nothing and twice as better as a household plug.

TT-30
Many RV suppliers sell an RV “50 AMP to 30 AMP” adapter cable. THESE WILL NOT WORK WITH THE TESLA as they are wired incorrectly for the TESLA. However we can use one of these adapter cables, cut off the NEMA 14-50 end (and throw it out) and make our own Tesla adapter.

So, as usual, buy a Camco® PowerGrip™ Replacement Receptacle Female:

http://www.amazon.com/gp/product/B00192QB9M/ref=oh_details_o04_s02_i00?ie=UTF8&psc=1

And then a RV 30 AMP to 50 AMP adapter: Camco 55185 RV Powergrip 30M/50F Amp 18" Dogbone Electrical Adapter with Handles 125Volts/3750Watts:

http://www.amazon.com/gp/product/B000BUQOGI/ref=oh_details_o04_s00_i00?ie=UTF8&psc=1

Cut off the NEMA 14-50 part of the adapter. Carefully strip away the outer insulation trying to not also cut through the inner insulation of one of the wires, to expose the three wires.

Here’s where it gets a bit tricky. If you look at the FACE of a NEMA 14-50 RECEPTACLE, the bottom round prong should be connected to ground. For a 120V supply, Tesla wants the leftmost blade to be connected to the 120V hot, and the rightmost blade to be connected the 120V neutral (note this is opposite to what a typical household receptacle does).

The TT-30 PLUG has a round shaped ground prong. If you place that round ground prong on top, and have the PLUG facing you, the bottom left angled blade is the neutral (sometimes labeled W on the plug), and the bottom right angled blade is the 120V hot.

Connect the TT-30 round ground prong to the NEMA 14-50 round ground prong. Connect the TT-30 hot to the leftmost NEMA 14-50 blade when looking at the front of the NEMA 14-50 receptacle, assuming ground is at the bottom. Connect the TT-30 neutral to the rightmost NEMA 14-50 blade when looking at the front of the NEMA 14-50 receptacle, assuming ground is at the bottom. Leave the NEMA 14-50 neutral UNCONNECTED. Label it with a reminder to set the Tesla car’s charging app to maximum 24 amps.

If you have an RV you might also want to label the adapters as TESLA CHARGING ONLY, NO RV USE. Actually, this adapter should especially be labeled with that warning as both of these plugs/receptacles ARE used in RV parks and adapters that look just like this (but are wired differently) are used all the time in RV parks.

For Earlier Model S: 20A Maximum for 120V supplies:
By the way, I’ve used this adapter a couple of times for charging my Tesla, and the maximum current the Tesla would pull from it is 20A, even though I had set it for 24A.

***Update April 17, 2014: According to the discussion forums, it appears that if you have a recently built Model S (maybe 2014 onwards), there is no amperage draw limit with 120V, so you can use this at the full 24A.
 
dsinned said:
and it looks like with no connection to the 14-50's "neutral" at the EVSE, the adapter I have should work to provide an AC power source of 125Vac, up to 30A from a TT-30 outlet found at most RV Parks.
No, the adapter is not going to work for you. If I understand correctly, the JuiceBox has a 14-50 plug on it, and it gets power from the L1 and L2 of that plug, with no connection to the neutral of that plug. That would be the normal way to wire an EVSE.

The adapter you mention connects TT-30 neutral to the 14-50 neutral and connects TT-30 line to the 14-50 L1 and L2. As such, there is no potential between L1 and L2, i.e. no power. So your JuiceBox will get no power. [The point of the adapter is that it will power the 120V circuits on both legs of an RV with a 240V/120V panel, although any 240V loads won't work.]

You could rewire your adapter to connect TT-30 neutral to 14-50 L1 and TT-30 line to 14-50 L2, then your JuiceBox would get 120V. I don't know anything about the JuiceBox, but I think you said it will work on 120V or 240V.

Cheers, Wayne
 
You need to build a combiner box that converts two OPPOSITE tt-30s to a 14-50. This box needs 2 relays for safety. I built one, and it cost me about 200 bucks. The design is simple, and is posted elsewhere on this forum. But if anyone want's to know, let me know and I'll draw it up scan a copy and post it on here.
 
Thanks to all for your feedback.

Wayne, your understanding is correct and remarks agree with the article I copied from the Tesla forum above. I need to get a shorty cord adapter, TT-30 male to TT-50 female, cut off the latter and rewire the remainder of the cord to a 14-50R female replacement such as this . . .

http://www.amazon.com/gp/product/B0...=UTF8&psc=1&smid=ATVPDKIKX0DER#productDetails

When rewired, the internal wiring would be like this, correct?

TT-30 male end . . . . TT-50 female end
Line (hot) terminal . . L1 terminal
Neutral terminal . . . . L2 terminal
Ground terminal . . . . Ground terminal
No Connection . . . . . Neutral terminal

The result would be a shorty cord adapter that passes thru 125V (30A max) single phase AC from the TT-30 power source (RV Park) to TT-50 125V single phase AC plug-in load (universal input EVSE). Then, all I have to do is make sure my JuiceBox is current limited to 24A.
 
Hello, I'm looking for someone to help me in the "idiots guide" fashion. Can anyone tell me with certainty if I wired my dogbone correctly and if not, can you help me get it wired correctly? One end is a Camco power grip NEMA 14-50P and the other is a Leviton 6-20R. I followed a guide that I found on the internet for wiring a 14-50R to a NEMA 6-50P. It seems to me that I should reverse the black and white wires on the Camco, but what do I know :D

My goal is to use a dryer outlet with a dual-voltage turbocord which uses a NEMA 6-20R outlet. I removed the neutral prong on the Camco adapter.

Thank you

Key
Black = Black wire
Red = White wire
Green = Green wire


My cord
LEAF%2014-50_6-20.png


The guide that I followed
http://visforvoltage.org/sites/default/files/u30/NEMA%206-50%20to%2014-50.jpg
 
Yes you wired it correctly, note you really should have used red/black/green wiring or if you only had black/white/green you could wrap red tape over the white jacket(or paint) where it's exposed on both ends. How your photo shows is exactly how I wired my dogbone and it works fine :)
I tried to find a definitive link showing the red wire should go to the combo pin(horizontal/vertical) and the black should go to the single horizontal pin but couldn't find one, which leads me to believe it doesn't really matter but again when I made mine I remember researching it and ended up doing exactly what your photo shows.
If you didn't wrap your white wire with red don't sweat it, or at least I wouldn't at this point.
 
Thank you JJeff! I'll take you advice and put some red nail polish on the white lead. I appreciate your help.
 
Back
Top