30 to 50 AMP upgrade

[Russell E Johnson]

OK, this is just a thought, and I am not sure I can do it, but here goes.  Our current set up in the 87 Southwind MH is 30 amp.  It will only run one AC unit at a time, of course.  When I had the 5500 KW Onan generator, it would run both AC units.

With that little bit of background, how difficult would it be to change the 30 amp service to 50 amp service so we have more reserve power and can run both AC units?  I am a shade tree electrician so please keep responses in simple layman terms. 

[Rich Thomas]

That sounds like a good conversation to have with John T. not knowing your wiring layout. would it be possible to do a split and run a dedicated circuit  for the second AC keeping the current 30 amp system and add a second breaker for the AC and up grade to the 50 amp shore power supply cable.  

[John "T" Nordhoff]

  It can be done, the only way I know how to tell you over the net is as briefly as I can (that's tough being an engineer and attorney lol) how it works (you probably already know) then you can look at your RV and wiring accessibility and figure it out.......

   There would be a 50 amp 4 wire Cord with a 50 amp 3 pole 4 wire grounding plug with 2 Hots, Neutral, Ground.

 That feeds a 120/240 volt 60 amp main service entrance panelboard with a 50 amp 2 pole main breaker.

 

  The panel MUST have isolated and insulated Neutral Buss and a Ground Buss THEY ARE NOTTTTTTTT BONDED TOGETHER LIKE IN HOMES MAIN PANEL You have two separate busses.

 You could then use a 120 volt 30 amp single pole branch circuit breaker to feed the old panel or existing wiring (excluding the second AC)

 You would use another 120 volt 20 amp single pole branch circuit breaker that ONLY FEEDS THE SECOND AC    NOTE!!!!!!!!!! THAT MUST BE ON THE OPPOSITE LEG AS THE 30 AMP BREAKER ABOVE   Coach and first AC on one 120 leg, and second AC on other 120 leg.

 So if you add a 4 wire 50 amp power cord and pug to feed a new 60 amp 120/240 Panelboard with a 50 amp main breaker, then have a 30 amp and 20 amp single pole breakers inside it, one feeds old panel (except for second AC)  other feeds second AC

 Nuff for now, get the picture????

 PS there are other short cut ways also, this is a more elaborate method

 John T

  

[Russell E Johnson]

OK, I get the picture.  Now silly question time.  The generator side had to be already wired for 50 amp as it would run both AC units and the rest of the MH.  Couldn't I just tie into that with a 50 amp cord?  and then have a manual switch, or automatic, so when the generator is turned on the power cord feed is disconnected?  

[John "T" Nordhoff]

  Rusell, that sounds like it would work, easier and cheaper. However, I would NOT want any sort of an automatic changeover, I see them fail too often plus they are pricey. You can EITHER use a 4 pole manual selector switch (shore v genset)  OR even easier and cheaper, mount a regular RV 120/240 50 amp 3 pole 4 wire grounding receptacle/outlet (same receptacle they have at an RV park for 50 amp service) which is fed from the gensets 120/240 50 amp output and then while driving or dry camping plug your RV shore power cord into it but if at a 50 amp RV park plug the cord instead to the RV pedestal. That's how my genny and RV cord is configured, when driving or dry camping I plug into the genests receptacle but if at an RV park I unroll the cord and plug into the parks power.

 NOTE you must switch ALL FOUR WIRES not just 3. That's why a simple 120/240 volt 50 amp outlet (fed off genset) is so easy and cheap because you either have all 4 plugged into it or the parks power, you switch all four conductors that way. ALSO the genset must have its Neutral bonded to the case/frame (NOT a floating Neutral) and the case/frame bonded to the RV chassis. 

 YES I realize this may take some re configuring versus what you now have, but its not much more then some 50 amp 4 conductor RV power cord (to replace your 30 amp 3 wire) and installing an outlet. My genset outlet is in the same storage box where my power cord is kept.

 John T

[Russell E Johnson]

"OTE you must switch ALL FOUR WIRES not just 3. That's why a simple 120/240 volt 50 amp outlet (fed off genset) is so easy and cheap because you either have all 4 plugged into it or the parks power, you switch all four conductors that way. ALSO the genset must have its Neutral bonded to the case/frame (NOT a floating Neutral) and the case/frame bonded to the RV chassis. "

The generator we will be putting in this summer has a 50 amp outlet on it,  So having a power cord that either plugs into the generator or shore power sounds like the easiest way to get around wiring up for 50 amps.   can just tap into the generator side of the control panel and then put the male end where I want it.  

Thanks John T, your help has been invaluable.  This project just became something I can do.