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Last seen: 3 weeks 4 days ago
Joined: Wednesday, July 15, 2009 - 15:49
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I don't know what to put this under except maybe Chargers and EV forum. I like to do things safely if I could possibly do things. Under the National fire protection there is a set of books called the NEC for one and under the national electric code getting electricity ends at the receptacle. I called Quincy Massachusetts and it is there. What you do after the welder outlet or toaster outlet in up to end user. Me? There is a chapter of all the common receptacles like Leviton's NEMA 5-15 outlet and how to hook it up. There is articles on grounding too 250.

Then there is Underwriters laboratory standard like for fork lifts and battery compartments and fusing, and cord safety for some mentions. Also there is IEC which made a new category of receptacle for world wide use. The old TV's use to use a safety power plug so when one took off the back cover it was no longer energized. A lot of good that did for the dag was hot like on the order of kilo-volts on the dag. So back to IEC C-13 the common computer receptacle and most "bricks" are 90 to 250 volts AC and some might just have a switch for a split voltage like 90 to 130 volts in and the other side 180 - 250 volts AC. I use the C-13 like other people on the list and don't convert it, cut the plug off and use a NEMA 6-20 or NEMA 6-15 when I use it where there is only 240 volts. The higher power battery chargers from China whether it be Alibaba or Hong Kong distributors sell them with IEC C-13 and I request both voltages or just 240 volt AC. In my years of doing EV, I noticed that the first real component in a switch mode charger is a Full Wave rectifier. So that means it is good for solar panels too. They tend to make DC usually. Most panel have 312 to 500 volts or more. So if you have like me a 350 volt panel then you can plug in a switched mode charger directly.

Now my quandary is what is the best and safest way of a standard plug /outlet / receptacle for "all" voltages? The reason I ask is because of new charging standard of Level 2 called J-1772 208 / 240 volt input to EV. I now charge exclusively by 240 volts whether it be slow charge on my XM-3000 or fast charge on my KIA at 50 amperes all at 240 volt AC and usually an appropriate plug. But I have to convert J-1772 to a Made in China 15 amp battery charger or Progressive Dynamics 240 volt switched mode battery charger or Iota too. All 240 and most use a NEMA 6-15 or 6-20 plug and some use a NEMA 5-15 plug which is a standard 120 VAC 15 amp plug.
So are there J-1772 police or NEC police to monitor proper usage? Even seasonal lighting is mentions in NEC and I see Christmas lights up all year too and no one says anything about them being used or just staying up all year. Supposed to be 90 limit? So getting J-1772 to a double outlet with both NEMA 5-20 and 6-20 in a box could be unsafe? But all my bricks say 100-250 volt so I ain't exactly worried but if I accidentally plugged in a table lamp it will go poof in short order.
Now I do know on this Visforvoltage forum there are a lot of wicked smart people / engineers / technicians out here. So feel free to voice your comments. Also the new European standard outlets seem to accept a round pin with NEMA 5-15 in same outlet? Wow!!! Do I use that scenario too? reason is in Europe they use 240 volts and I can plug in my laptop brick. Or use my tower and move switch to 240 with stock IEC C-13 and NEMA 5-15 plug. So many choices. Safety is main concern but functionality is more useful.

reikiman's picture
Last seen: 11 months 23 hours ago
Joined: Sunday, November 19, 2006 - 17:52
Points: 8447


I'm sure I'm violating some code or other but that's exactly what I'm doing.

To start with here's the warning label on my J1772 adapter. It's a little box w/ J1772 on one side, and a NEMA 14-50 on the other. I believe you already have one?


I have built a cord that goes from NEMA 14-50 to NEMA 6-20R, which is shown here next to my AVCON adapter


I settled on NEMA 6-20R for the bulk of the charger wiring inside the car, because the ELCON PFC3000 charger came with a NEMA 6-20 plug. However, powering up the BMS requires a 12 volt power adapter that can run on either 120 volts or 240 volts. The car won't charge unless the BMS is powered up.

To do this, I got one of the plastic junction boxes at Home Depot, one sized for four power outlets. On one side of the junction box I wired a normal NEMA 5-20 power outlet (has two outlets) and on the other side of the box I wired a NEMA 6-20 power outlet. Both these outlets are wired together. As an input to the box I wired two pigtails, one with a 120 volt socket, the other with a 240 volt socket. Everything is wired together such that if the 120 volt pigtail is plugged in, the power outlets have 120 volts, and if the 240 volt pigtail is plugged in, everything gets 240 volts. Because everything can take 120-240 volts, it all works.

There's an additional junction box in which I installed a pair of AC meters showing voltage and amperage.


A little safety item I've done is to use matching sockets so the pins are safely hidden. That is, you won't connect both the NEMA 5-20 and 6-20 at the same time, one of them will be disconnected but have live voltage on its pins. By putting a non-connected socket over the unused plug, it'll keep the pins from accidentally connecting to anything.

This probably violates the codes - e.g. the way it's set up, 240 volts will appear on a socket meant for 120 volts, and vice versa, depending on what power source this is connected to.

But it works for me, and so long as I operate this in the correct way it'll be safe. This is because the gizmos I plug into this run at either 120 volts or 240 volts.

But for example if someone saw that empty 120 outlet, and plugged in a 120 volt only gizmo while the car was charging off a 240 volt service, that 120 volt gizmo would blow up.

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