Generator Wiring

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  #1  
Old 08-14-13, 09:20 PM
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Generator Wiring

Im replacing a 8k diesel generator with a 12k generator at my offgrid cabin. the wiring that is inplace from the gen shed to the panel in the cabin is #2 Al xlpe RHH RHW use-2 (4 seperate conductors) . the distance is around 40 feet from shed to panel. the last gen pulled around 34 amps (amp meter showed)on each of the hot legs when fully loaded. the new gen will have a 100 amp max and 86 amp continuous rating. My question is will the #2 aluminum be big enough for the 12k gen? from what i could find briefly looking #2 aluminum sometimes is and sometimes isnt big enough for 100 amp panels? Dont really care about the code as there isnt any inspection but want be be safe. any advise id be thankful for.
 
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Old 08-14-13, 09:51 PM
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A 12,000 watt generator supplies 50 amps at 240 volts. Where do you get 86 amps? 86x240=20640 or 20.64K Am I missing something?
 
  #3  
Old 08-14-13, 10:02 PM
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those values (100max, 86 continuous)are for 120 volts . at 240 its 50 amps so does that mean the #2 Al wire is good for 100 amps (50 amps on each of the 120 hot wires)
 
  #4  
Old 08-14-13, 10:55 PM
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There will never be more than 50 amps per leg. Your generators maximum output at 120 volts is 12kw. or 50 amps per leg to neutral.

So your #2 wire is plenty large enough to handle the load transfer.
 
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Old 08-15-13, 12:50 AM
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You could almost use #6. #4 would be good.
 
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Old 08-15-13, 07:46 AM
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thanks guys for taking the time to answer my question. Now if i could ask one more thing. the 8k gen has a cable running from it to a recepticale in a junction box on the wall which allows the generator to be unpluged. the plug-recepticale looks like a plug used on a welder or RV and it has a cable with 4 wires (all in one cable). the wire cable says # 6 on it. im guessing its a 50 amp plug and recepticale with the # 6 wire. do you think i could use this same wire and receptical on the 12k or should i put a bigger wire size and a larger plug receptical on it? If so what size wire and what amp plug receptical?
 
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Old 08-15-13, 09:28 AM
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If the plug and receptacle is a 14-50 yes. That should be marked on the receptacle.
 

Last edited by ray2047; 08-15-13 at 10:45 AM. Reason: Wrong answer.
  #8  
Old 08-15-13, 10:04 AM
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it says on the recepticle NEMA 14-50R

here is a pic at this web page of the exact one

Pass Seymour 50A Surface Mount Range Outlet 3854CC6
so then this should be ok.
 
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Old 08-15-13, 10:44 AM
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That is the correct one I gave the wrong one in my reply. You mentioned welder and my brain just didn't click in. You do have an inlet not the receptacle shown on the house side, correct?
 
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Old 08-15-13, 11:59 AM
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not sure what you mean by this statement "You do have an inlet not the receptacle shown on the house side, correct?"
the pic i showed of the female part of the plug-receptacle assembly is on the generator cord coming straight off the generator head and the male part of the plug-receptacle assembly has a short cord that comes off the junction box with the male prongs that plugs into the female part attached to the gen cord . im not sure this is right, but when the generator is running and unplugged there isnt any exposed male plug with juice going thru it this way. its lke opposite the way an appliance would be hooked up but when an appliance is unplugged there isnt any power flowing to the expossed prongs.
im no electrician as you can tell just a basic understanding of this stuff.
 
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Old 08-15-13, 12:14 PM
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So are you saying the cord is hard wired to the house electrical not plugged in? If so that is okay.
 
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Old 08-15-13, 04:58 PM
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the cord(#6 4 wire) that plugs into the generator female receptacle (14-50) that same cord (#6 4 wire)is hard wired into a pull box on the gen shed wall from where the #2 conductors then run thru conduit underground into the breaker box which is in the cabin.
so the cord is hard wired into the pull box which feeds the cabin breaker panel but that same cord then plugs into the receptacle (14-50)on the generator.
i could change it if its wrong but the way it is allows the generator to be removed by simply unplugging the cord from the generator. i might add that the receptacle(14-50) mounted on the generator feeding the full generator current to the pullbox has a breaker (35amp)right before it. the new 12k gen has a 50amp in the same spot so all id have to do is put the same 14-50 receptacle on the new 12k generator and plug the existing cord running into the pull box into the 14-50 receptacle. unless of coarse there is something unsafe with this arrangement.
 
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Old 08-15-13, 06:37 PM
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all id have to do is put the same 14-50 receptacle on the new 12k generator
You shouldn't need to change the receptacle on the generator. You should use the receptacle the generator comes with. What is wrong with that receptacle.
 
  #14  
Old 08-15-13, 08:16 PM
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the generator doesnt come with a receptacle on it. the generator just comes with a small breaker box with a short cable run right off the generator leads. this type of generator is geared toward direct hardwire for off grid applications. i could skip the receptacle and just wire right from the generator breaker box straight to the pullbox on the shed wall but i would have to unwire the cable if i ever had to take the gen out for any reason. thanks again for your input
 
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