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Generator custom Y connection - two 120v to one twist lock

Generator custom Y connection - two 120v to one twist lock

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  #1  
Old 11-07-12, 10:19 AM
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Generator custom Y connection - two 120v to one twist lock

Hi,
I have a buffalo tools propane generator that has only two 120V (15A each) outlets but no twist lock outlets. In order to power to my house, I need to have a twist lock outlet. Alternatively I could just run power cords to my appliances drawing from both outlets. But that is not my final goal.
Here is what I am thinking:
There will be two regular 15A male plugs going into the generator outlets and one female twist lock outlet as a result of this Y connection. In the Y connection, combine the two neutrals, two ground together and have the two hot wires connected to a female NEMA twist lock plug. Does this modification sound like a 'no-no' or would I be breaking any codes or insurance laws as a result of this?
My other option is to sell the generator and get one with a twist lock outlet.
All the other posts talk about making a Y connection from a twist lock to two female 120V outlets but mine is kinda reverse. i.e two 120V making a twist lock outlet.
 
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  #2  
Old 11-07-12, 10:33 AM
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Your gen is 120v only? You want to go 3 wire to 4 wire?

What type of twistlock is at the house and what transfer switch do you have?

How big is the gen? You can overload the multi wire branch circuits from what I know. I believe its best to keep under 2000 watts or so.

I doubt code allows it anyway.

Your best off getting a gen with a twist lock. Keep that gen as a spare and use it to run with cords.
 
  #3  
Old 11-07-12, 10:46 AM
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Thanks for the response.

Here is my ideal setup. Propane/Natural gas generator with a 120/240v twist lock outlet connected with 4 wire extension cable to an twist lock outdoor outlet box which feeds into the main switch panel. I will be installing the interlock kit on the main switch panel.

Here is what I currently have: Propane generator(looking to convert to natural gas with a kit) with two 120V(15A each, 3 wire each) outlets. I need to run extension cable to the twist lock outdoor outlet box. The outdoor outlet then feeds into the main switch panel as indicated above.

So the issue here is the Propane generator having two 120V outlets instead of the twist lock outlet. Hope this makes the situation clear. The outdoor outlet box and the interlock kit are yet to be installed.

Please throw in your valuable ideas and suggestions.
Thanks
 
  #4  
Old 11-07-12, 11:01 AM
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With the unit running, measure the voltage between the hot prongs of the outlets. The answer will determine how to proceed.
 
  #5  
Old 11-07-12, 11:16 AM
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Hi,
Just a note: I will not be running any 240V appliances with this connection. Would you still ask the above question in that case? Thanks
 
  #6  
Old 11-07-12, 11:26 AM
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Yes, because your panel is designed for 240v feed not 120v. It is possibile to feed it with 120 volts as long as certain conditions are met.
 
  #7  
Old 11-07-12, 11:44 AM
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What is the make and model generator?

Not sure how its wired but I would assume both windings are used @ 120v from both outlets.

No 240 loads?

Best bet is to get a 120v only transfer switch.

Gentran Corporation: Generator Transfer switches for home & business

Wait for the electricians to chime in.
 
  #8  
Old 11-07-12, 12:10 PM
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Auger: The hot prong voltage between the leads is 118v.

The make of the generator is Buffalotools - sportsman GEN4000LP.
Link to the Manual is below
http://www.buffalotools.com/manuals/gen4000lpmanual.pdf

No 240V loads for sure.
 
  #9  
Old 11-07-12, 12:13 PM
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You may not do that. (Y connector with two 120 volt plugs and one 120/240 volt twist lock receptacle)

Under some conditions you can end up with one of the male plugs loose with prongs live.

1. Connect it up to the two generator receptacles as you described.
2. Generator is running.
3. A 240 volt appliance in the house is switched on.
4. One of the two plugs falls out of the generator receptacle.
5. Power from the live half of the house system finds its way through the 240 volt appliance and appears on the dead half and at the loose plug. This happens whether or not the generator is 120 volts only feeding both of its receptacles or is 120/240 volts with one receptacle on each side of its circuitry.

You would be restricted to having just one (male) plug cabled to the twist lock receptacle where the single hot wire would be pigtailed to both hot prongs.
 
  #10  
Old 11-07-12, 01:05 PM
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That is weird. The voltage between the hot (right) prongs of the plugs should be either 0 or 240.

It would probably be cheaper to sell it and get a proper generator for your setup rather than attempt to modify the hose and generator to make it work.
 
  #11  
Old 11-08-12, 07:24 AM
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It sounds like you have a small 120v generator. It's probably about a 1500w generator or so?

Question to the pros- could the OP just use one 5-15P plug into the generator wired to both hots on the twist lock? Only 120v appliances could be used, but at least it would work and be safe?
 
  #12  
Old 11-08-12, 08:14 AM
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Auger,
Sorry I must have been dreaming when I wrote that. The voltage between the two hot leads was 0v.
Thanks
 
  #13  
Old 11-08-12, 08:18 AM
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Zorfdt,
No, not that small. The generator spec says 3250 running watts and 4000 peak watts. The problem is that there are only two 120V outlets from the generator. If we use only one 5-15P into the generator then the max power that can be drawn is around 1800 watts. What I was hoping for is to write the two hots from the two outlets into a 5-30 plug so that I can draw 15A from each circuit to a total of around 3000 watts.
 
  #14  
Old 11-08-12, 09:33 AM
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My thought would be two cords to two inlets to one three pole transfer switch. Each of the hots would go to one side of a two pole breaker box. The question is could you safely combine the two neutrals from the generator. That I don't know. A schematic of how the coils are wired in the generator might answer that question. Of course it might be possible to wire for one higher amp receptacle as suggested by Lwarosa. That would mean replacing the two receptacles with on 30 amp receptacle and changing the OCPD to 30 amps. Probably a lot simpler to get a different generator or take it to a motor shop and see if it can be rewired.
 
  #15  
Old 11-08-12, 09:43 AM
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The PDF linked to shows the output as 120 volts only.

I will agree that the best is to get a genset with 120/240 output.
 
  #16  
Old 11-09-12, 01:50 PM
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The voltage between the two hot leads was 0v.
That sounds like a single 120V leg. That is, your generator is 120V only.

You could use the two outlets to feed a small transfer panel with your critical circuits relocated to that panel, if you made the necessary modifications to the transfer panel, or bought one that was 120V only. You should not connect this generator to your house panel.
 

Last edited by Nashkat1; 11-11-12 at 05:33 PM. Reason: cleanup
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