Posted: 12/17/2013 3:31:29 PM EDT
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Is it possible to go from a L5-30 to a 14-30?
Using an interlock on main breaker panel in the house, is it possible to power both sides of a 200 amp circuit breaker box providing the load limits are met using the above cord? There is a single hot 125 leg on the L5-30 and two hot legs on the 14-30. This would allow me to use a large generator to run my 250 volt well pump using a 14-30 to a 14-30. Using the above mention cord would allow me to (breakers off on ALL large draw item INCLUDING the well pump) run on minimum power using a Honda 2000. Thanks in advance as my "go-to electrical genius guy" has gone "off-grid". |
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no. the L5-30 is 120 volt. splitting the same 120v line into two other wires is still just 120v.
I think I mis-understood. you can do this and run 120v loads from the cable you mention. i wouldn't reccomend this, but if you did turn off all the double pole breakers, it should be ok. you can then figure out a way to connect a 220v generator to the well pump. |
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The answer is "a remote maybe" but for you it's probably "a bad idea."
In normal household service the two hot legs have 240V potential between them, and 120V between each and neutral. If you're ONLY powering 120V devices on each leg, you could get away with it, but anything that needed 240V wouldn't work. I would want a crapload of interlocks to prevent the 240V loads from connecting, even though in theory they should see 0V across the hot pair. I've done what you've suggested on a small cabin before, but we knew 100% of the wiring and loads -- actually designed the electrical system so there was zero 240V loads. |
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I provide no warranty with this advice, but if all the loads are 120V and there's nothing wrong with the wiring
then this will work, as I've done it myself. Each hot branch is 120V so it's just a bunch of circuits sharing the neutral, connecting the hots won't be an issue. Note that if there is an interlock failure with grid power or a 240V generator source, this is going to present a dead short across the 240V input, and that, I do guarantee, will result in bad things. Hopefully the breakers would blow before anything else, but given it'd likely be the main service breaker at a full 200 amps, I'm betting the plug that does the shorting would be turned into a molten puddle before the main breaker blows. This is why I say generally a bad idea. (The cabin I did this at didn't have mains power and only one generator input, so there was literally no way it could fail like this.) |
Yes, I have done this successfully for a situation similar to what you are describing. However, I have a generator transfer panel set up with NO 240v loads on it at all. (I have city water and a gas fired boiler). As the other posters have said, it can be done- but do it smartly! 
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| ar-jedi has shown this many times, one of the latest being here. |