Do It Yourself: 240v from two 120v sources

+1!!

Edit: BTW, for the buzzer, wouldn't it be simpler to add a switch & buzzer in series and just turn it off when you've got it set up? Although the perfect circuit would auto-shut off the buzzer after a few seconds, then activate it again if one of the plugs gets pulled out and/or one circuit trips.

Luft said:

I'm interested in a kit with the buzzer. It just makes sense to me to have the device give me an audible signal that everything is a go.

garygid said:

OK, we appear to have enough interest in a Kit, so we need to price and source a specific Parts List for this particular Kit.

I just started a "120-to-240 Adapter Kit (Rev 1)" thread for further details on this specific Kit-Project.

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Luft said:

I'm interested in a kit with the buzzer. It just makes sense to me to have the device give me an audible signal that everything is a go.

garygid said:

OK, we appear to have enough interest in a Kit, so we need to price and source a specific Parts List for this particular Kit.

I just started a "120-to-240 Adapter Kit (Rev 1)" thread for further details on this specific Kit-Project.

Click to expand...

Click to expand...

Haven't gotten around to building mine yet, so definite interest in a kit--with our without buzzer. To those on the effort, many thanks.

Will follow the other thread then..

That box is a Carlon weatherproof junction box that I got at OSH.

I used a 1.5" hole saw to make the hole, and then the L6-20 receptacle needs it's tabs bent just a hair, and it fits perfectly.

-Phil

The tabs on my receptacle proved hard to bend so I used a bolt cutter to trim them.

Ingineer said:

That box is a Carlon weatherproof junction box that I got at OSH.

I used a 1.5" hole saw to make the hole, and then the L6-20 receptacle needs it's tabs bent just a hair, and it fits perfectly.

-Phil

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I must not be looking in the right place.. didn't see anything like that @ my local OSH. Thanks! I'll look for it again.

lincomatic said:

I must not be looking in the right place.. didn't see anything like that @ my local OSH. Thanks! I'll look for it again.

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I picked up that exact same box in Home Depot's electrical section.

Here's the parts list for the components I used. Total cost was about $50 + tax + shipping.

(2 pcs) MAGNECRAFT - W9AS5A52-120 - POWER RELAY @ $4.46
(1 pc) NEON LAMP T-1 1/4 WIRE LEAD 1.8mA 240V @ $0.30
(1 pc) RESISTOR, CARBON FILM, 100KOHM, 250mW, 5% @ $0.02
(1 pc) NEMA L6-20 Grounding Outlet @ $9.99
(1 pc) Weather-tight plastic enclosure, IP-65 rated, 4.92 x 3.35 x 2.17 inch @ $6.66
(2 pcs) Conduit Cord Grip Connector 11.4mm @ $2.59
(2 pcs) 10 Ft. 14 Gauge Outdoor Extension Cord @ $7.49
(4 pcs) 0.187 inch quick-connect terminal connector (from local hardware store)
(4 pcs) 0.25 inch quick-connect terminal connector (from local hardware store)

First I drill a large hole in the box lid for the outlet to fit in. The outlet fits inside at an angle and two small holes are drilled to attach it with two small bolts. The cord grip connectors are mounted in the side of the box itself, placed appropriately to not get in the way of any interior components. Cut the female receptacles off the two extension cords and insert them through the cord grip connectors.

Attach short lengths of wire to the L6-20 outlet before mounting the relays, as the relays will block access to the screws on the outlet. I mounted the two relays onto the lid on either side of the outlet using double-sided padded sticky tape. It seems to hold well, and of course was very easy. Use Ingineer's wiring diagram. The relays I chose are identical to the ones he recommended, except these have both NO and NC pins and oddly they cost a little less. Simply use the NO pins and ignore the NC ones.

The resistor is to protect the neon lamp. Solder it in series to one lead of the lamp and then attach it across the L6-20 outlet so when the outlet is energized the lamp will glow. Drill a very small hole in the lid for the tip of the lamp to poke through. Then double-check all the connections and carefully close the box. That's about it.

Of course it shouldn't need to be said, but, only attempt this project if you are well aware of what you are doing every step of the way. You're assembling something that will handle high voltage and current, and you don't want to start a fire or get someone shocked.

For my (still in progress) easy240 I mostly went with johnr's parts list, except I went with the relays Ingineer originally recommended, but I'm kicking myself for that decision now. I also got a switch like Ingineer showed in one of his later schematics, because I like the idea of being able to use the unit as a 5-15 to L6-20 adapter / extension cord when there aren't two out-of-phase circuits available. (I'm doing the one long cord and one short cord method.)

However, after I got my parts and was laying everything out, it occurred to me that had I gotten johnr's SPDT relays I think I could've skipped the switch, which would be nice as the box johnr used is rather compact, and it's one less hole to drill and 2 less lugs to crimp. If I were to connect the neutral from my long cord to the NC terminal on the relay whose coil is connected to my short cord, that would achieve the same function as Ingineer's switch, automatically, no? I.e. if the short cord is unplugged, it serves as a long 5-15 to L6-20 adapter, whereas if the short cord is plugged in, it does 240v. I've convinced myself enough to go ahead and order an SPDT relay and skip drilling a hole for the switch, but if anyone sees a problem with this please let me know.

Also, I got this lamp to avoid soldering the led and resistor, and because it's nice and big. This is a better choice than the lamp linked to earlier in the thread as Newark tacks on a $20 handling charge if you get that one. And I skipped the L6-20 receptacle because I'm going to use an L6-20 pigtail that I ordered with my EVSEupgrade, which means I also got 3 of the cord grips instead of 2. If you're going to order from Newark you should note shipping for me was over $8 (there's no way to see what your shipping charge will be until after your order is processed) and they charge almost 10% sales tax even if you're out of state. Also the cord grips don't come with locknuts, and the only ones Newark sells are $24 for a 50 pack. What did you do for locknuts johnr? Hopefully that's something that's easily remedied when I go to the hardware store, as I still need to pick up some terminal connectors too.

Oh, and I'm using 2 of these extension cords because I don't like the idea of using 14awg wire (although it's probably fine, I'm just playing it safe.)

I've got a stupid question if anybody is still following this thread. I'm thinking about making a 5-15r to l6-20p adapter so my 12 awg 120v extension cord can double as a 240v extension cord in the rare case that I might need some extra long reach. Also, as I mentioned in my previous post I want to use an SPDT relay so my easy240 can double as another 120v extension cord by bridging the long cord neutral to the l6-20r when the short cord is unplugged.

So, if I want to use the easy240 in 120v extension cord mode, but using an adapter to carry 240v, would passing 240v through a relay coil fry it?

fooljoe said:

I've got a stupid question if anybody is still following this thread. I'm thinking about making a 5-15r to l6-20p adapter so my 12 awg 120v extension cord can double as a 240v extension cord in the rare case that I might need some extra long reach. Also, as I mentioned in my previous post I want to use an SPDT relay so my easy240 can double as another 120v extension cord by bridging the long cord neutral to the l6-20r when the short cord is unplugged.

So, if I want to use the easy240 in 120v extension cord mode, but using an adapter to carry 240v, would passing 240v through a relay coil fry it?

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The 120V adapter is so small and easy to use, why bother having a large box to use for this and risking someone taking it, etc.? Keep it simple.

EVDRIVER said:

The 120V adapter is so small and easy to use, why bother having a large box to use for this and risking someone taking it, etc.? Keep it simple.

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This is just a hypothetical question in the case that I need an exceptionally long run to get to a 240v outlet at someone's house (a dryer outlet upstairs, e.g.) Since I already carry around the easy240 with a long cord, and it can double as a 12 awg 120v extension cord if I don't plug in the short cord, the question is could it also work as a 240v extension cord, provided I have an adapter for the male end? Of course the wire is suitable, but would passing 240v through the relay coil fry it?

I already have a 25' L6-20 extension cord, but I'm talking about the rare case where I'd need that plus another 25' or more.

fooljoe said:

EVDRIVER said:

The 120V adapter is so small and easy to use, why bother having a large box to use for this and risking someone taking it, etc.? Keep it simple.

Click to expand...

This is just a hypothetical question in the case that I need an exceptionally long run to get to a 240v outlet at someone's house (a dryer outlet upstairs, e.g.) Since I already carry around the easy240 with a long cord, and it can double as a 12 awg 120v extension cord if I don't plug in the short cord, the question is could it also work as a 240v extension cord, provided I have an adapter for the male end? Of course the wire is suitable, but would passing 240v through the relay coil fry it?

I already have a 25' L6-20 extension cord, but I'm talking about the rare case where I'd need that plus another 25' or more.

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I thought about using extension cords with 120V plugs for 240V and decided against it. Even though the chance is small, someone might play with the plugs and connect a 120V device to 240V and "let the smoke out". You'd likely "let the smoke out" if you connected 240V to a 120V relay coil, especially for any length of time. I have much less problem with the 120V to 240V adapter, which allows 120V on 240V extension cords for the modified EVSE for 2 reasons: (1) 120V is less likely to fry a 240V device, if someone inadvertantly uses the extension with another device. (2) Devices with L6-20P are not so common around most homes. Other than the modified EVSE and the cords you use with it, how many devices do you have at your house which use this plug?

My recommendation: get another L6-20 extension if you think you'll need more length. I made 2 40ft 10AWG L6-20 extensions; I've only needed 1 so far, but I've got another just in case.

tps said:

My recommendation: get another L6-20 extension if you think you'll need more length. I made 2 40ft 10AWG L6-20 extensions; I've only needed 1 so far, but I've got another just in case.

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I agree with this. By the time you're done making an adapter to turn your Easy240 wiring into a 240V extension cord, you'll probably end up spending enough money that maybe with just a little bit more would have bought you another straight and simple 240V extension cord; instead of having to risk frying out your Easy240 relays just to save a few bucks, let alone risk safety and equipment hazard in case somebody (or yourself) do something dumb without thinking or remembering and plug in the other end of the Easy240.

I bought two 15ft and one 25ft 240 L6-20 extension cords so I have various length combinations at my disposal: 15, 25, 30, 40, or 55 ft so I can minimize unnecessary voltage drop by being able to run the shortest length combination that will reach the outlet.

Here's my finished product:

Sorry about the iphone pics. The voltmeter shows 236, I promise.

Here are its innards:


The relay on the left (relay 1) is the SPST, on the right SPDT (relay 2). The black cord on top is the L6-20 pigtail, the yellow on the left is the long cord that can double as a 120v extension cord. The indicator lamp is poking out of the lid.

The wiring:
Relay 1:
c1: small gauge (I used black 16 awg from an old extension cord) wire connected to long cord black
c2: 16awg white connected to long cord white (c1 and c2 are red QCs on top)
NO: long cord black with other end of 16awg black from c1 crimped in (yellow QC on left)
COM: L6-20 black with indicator black lead crimped in (yellow QC barely visible under red QCs)

Relay 2:
c1: 16awg black from short cord black (red QC)
c2: short cord white (blue QC)
NO: short cord black and 16awg black crimped together (clearly visible yellow QC on left)
NC: long cord white crimped with 16awg white going to relay 1 c2 (yellow QC you can't see under the NO terminal)
COM: L6-20 white with indicator red lead crimped in (yellow QC under red and blue QCs)

All three green ground wires are twisted together as well, of course.

If you don't want the 120v extension cord / long adapter option relay 2 would be the same except without NC and relay 1 would be the same except c2 would be the long cord white directly, as with relay 2 c2.)

tps said:

My recommendation: get another L6-20 extension if you think you'll need more length.

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Well I'm already carrying around a 25' L6-20 extension cord and a 20' 5-15 extension cord (what was left from the "short cord" on my easy240), and the easy 240 itself is effectively a 25' L6-20r to 5-15p extension cord. With all of that plus the upgraded EVSE, my trunk is getting pretty crowded, not to mention those L6-20 extension cords are fairly expensive. All these cords are the same 12/3 wire, so it's just the ends that matter. And I don't see any safety risk at all, since the female end of the easy240 is the L6-20 outlet.

I'm think I'll probably give this a try at some point. After making the easy240 I have a leftover 5-15r with a stub of cord that got chopped off one of my yellow extension cords, so all I need is an L6-20p. Plus I happen to have a relative that lives 65 miles away and has an upstairs dryer outlet. I also have an extra SPST relay after the last minute design change to use an SPDT, so if I fry a relay it's no big deal. But I'd probably take a small piece of 12awg wire with male QCs crimped on both ends to bypass the relay and connect the long cord hot to the L6-20 black wire directly if I ever did this.

fooljoe said:

Here's my finished product

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Very good!

fooljoe said:

I also have an extra SPST relay after the last minute design change to use an SPDT, so if I fry a relay it's no big deal. But I'd probably take a small piece of 12awg wire with male QCs crimped on both ends to bypass the relay and connect the long cord hot to the L6-20 black wire directly if I ever did this.

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I could be wrong for your particular relay, but my guess is that a 120VAC relay coil will fry when connected to 240VAC. Seems like the maximum coil voltage at which many nominal 120VAC relays are designed to operate is 110% of nominal, or 132VAC. Maybe you could test it at home, first. Please let us know what happens!

Thanks to fooljoe I was able to put one of these together. I choose to go with the two extensions coming in and connecting to the relays then to the recepticle. I used the larger or double gang plastic box, but with the lamp that fooljoe proposed it was a tight fit. I tried it out and it does work. I am not sure what purpose the relays provide? Could I have just connected directly to the recepticle via the two incoming extensions? I would have mated the commons and grounds and just connected the two hots to x and y. Adding the light lets you know you have 200 + volts.
Manny

drmanny3 said:

I am not sure what purpose the relays provide? Could I have just connected directly to the recepticle via the two incoming extensions? I would have mated the commons and grounds and just connected the two hots to x and y. Adding the light lets you know you have 200 + volts.
Manny

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Yes, it would work the way you describe it, but you would have to be quite careful with the unit yourself and very vigilant in keeping others from messing with it - the relays stop the backfeed of 120v across the second incoming plug while the first one is plugged in.

drmanny3 said:

Thanks to fooljoe I was able to put one of these together. I choose to go with the two extensions coming in and connecting to the relays then to the recepticle. I used the larger or double gang plastic box, but with the lamp that fooljoe proposed it was a tight fit. I tried it out and it does work. I am not sure what purpose the relays provide? Could I have just connected directly to the recepticle via the two incoming extensions? I would have mated the commons and grounds and just connected the two hots to x and y. Adding the light lets you know you have 200 + volts.
Manny

Click to expand...

I'm not sure what you mean by "commons", but if you mean the neutral (white) wires from the extension cords you would not connect them like you do the grounds. You would just terminate them. But again doing it without the relays is not advised: If any device is connected to the L6-20 which bridges X and Y, then the hot prong on a detached cord would be connected to the hot on the plugged in cord. So if someone happened to unplug one of your two cords and touch the hot prong they could get shocked. The relay prevents this scenario by keeping the connection from either extension cord to the L6-20 open unless the cord is plugged in.