Question about generators/transfer switches

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  #1  
Old 11-14-11, 05:09 PM
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Question about generators/transfer switches

I have a Gentran transfer switch professionally wired to my circuit panel box. I am upgrading from my Coleman 2250 generator to (hopefully) a 5000 watt generator. The Gentran transfer switch is rated for generators up to 5000 watts, and has a 20 amp 4-prong plug. However, any 5000 watt generators I can find all have 30 amp 4-prong plugs. Is this a problem, or are they compatible as long as the generator isn't run on full load? I'm confused about why a transfer switch can handle a 5000 watt generator, yet have a lower amp-rated plug than what standard 5000 watt generators have.
 
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Old 11-14-11, 06:27 PM
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Replace the existing inlet connection with a L6-30. Do a thorough Internet search because the cost will vary from about $15 (eBay?) to over $60.
 
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Old 11-14-11, 06:35 PM
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Umm...A L6 30 is a 3 prong.

I think he needs a L14 30 and probably upgrade the wire from inlet to transfer switch. I believe 10/3 for 30 amp?

Also possibly a bigger cord from gen to inlet with new ends.

Mike NJ
 

Last edited by lawrosa; 11-14-11 at 08:05 PM. Reason: Corrected 10/2 to 10/3 wire. I had brain freeze.
  #4  
Old 11-14-11, 07:13 PM
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Originally Posted by lawrosa View Post
Umm...A L6 30 is a 3 prong.

I think he needs a L14 30 and probably upgrade the wire from inlet to transfer switch. I believe 10/2 for 30 amp?

Also possibly a bigger cord from gen to inlet with new ends.

Mike NJ
Correct, a L14-30R is a 4-wire device, but that would require 10-3 NM cable and not 10-2 NM cable. If the cord from the genset must be increased, it would be a 10-4.
 
  #5  
Old 11-14-11, 08:38 PM
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Yep, you guys are correct, an L14-30. I was on my laptop and it has a bad screen. (How's that for an excuse?)

Of course he will also need to use a 10-4 interconnect cable. I am assuming (always dangerous) that his transfer panel has the inlet attached rather than remotely mounted. Quite honestly, if the transfer panel is rated for 5000 watts it should already be wired with #10 and I suspect the "professional electrician" that installed it changed out an original L14-30 for the 20 ampere inlet knowing it was to be used with a smaller generator.
 
  #6  
Old 11-14-11, 11:10 PM
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hey tv shooter- I just bought a Homelight 5000 watt generator with Subaru engine- its 240 120 has a 20 amp 4 prong output-It can handle 6250 starting and from what ive read its the continous watts that the transfer box rating is rated for not the starting-so your electrician set up your system to specifically accomodate your smaller generator but as you can see that some 5000 watt generators may have 20 amp 4 prong as well and your transfer switch should be fine at that higher wattage (be certain that your new 5000 watt generator has a floating nuetral) otherwise youll have a bonded neutral and a major task will be require to change your set-up- the box of my generator said it was floating neutral but the generator inside the box was actually neutral bonded to frame-pay close attention to that detail-good luck finding the right generator
 
  #7  
Old 11-15-11, 05:01 AM
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No, the electrician never replaced the inlet connection (he had no idea what generator I was using). The inlet connection is original to the transfer unit.
 
  #8  
Old 11-15-11, 09:34 AM
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20 amperes at 240 volts is 4800 watts. I don't agree with "overloading" the connectors but maybe it is industry standard when the overload is less than 5%.
 
  #9  
Old 11-15-11, 09:34 AM
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A lot of 5kW generators have the 20A receptacle, so it's not surprising your transfer switch had that one installed. It would be okay to replace your inlet with a L14-30 to accommodate the new generator.
 
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