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nat58

30 Amp Upgrade

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nat58,

Welcome to the FMCA forum!

Do you plan on doing the work or having it done?  It is not done just by changing a few wires. The connectivity of the 3 different sources of 120 volts requires the use of relays, solenoids, time delay relays and circuit breaker panels, connected so any two supplies are not connected to the same point at the same time.

A 30 amp system has one high side and a 50 amp system has 2 high side circuits, that fact kind of doubles the isolation issues. The 30 amp service supplies just 30 amps, but a 50 amp service supplies 100 amps.

A little of your back ground and skill sets would go a long way in how the project might be handled. So if you want to send me a Privet Message(PM) using that feature of the forum.Go to my profile page and open a conversation at the send me a message button.

Rich.

 

 

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I changed my 30 amp 93 Coachmen Santara to 50 amp.  Since you are an electrician you will understand what needs to be done.  I put in all new breakers on both sides of the 50-50 amp, then split the load.  When the gen closes the ATS one leg is 30 amp and one leg is 20 amp.

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Nathan, one thing to remember is that the circuit box in a coach is treated as a daughter box to the first, ie. earth ground is not bonded to neutral. The CG pedestal is where that must occur.

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50 amp RV and 50 amp house ARE the same.  It is 30 amp RV that differs from 30 amp house, as 30 amp RV has only a single hot while 30 amp house has two.

50 amp RV/House:

TWO hots (L1 and L2)

One neutral

One ground

There is another option to changing the whole system from 30 to 50 amp. Some have separated out the rear A/C to a separate feed. That separate feed can either be plugged into a CG 15/20 amp outlet or into a special adapter that, along with the coach 30 amp cord plugs into the CG 50 amp outlet.  Not as clean, but a lot less work and less expensive.

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Brett,

I understand the difference between house and RV electrical. Don't some of the newer Motor Homes have some 220 volt circuits? It seems that somewhere I heard or read some do. Am I wrong?

Herman

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Herman, L-1 to L-2 would read 220 volts. L-1 or L-2  to neutral will read 120 volts.

Some coaches have 2 inverters so there is 220 available.

Rich. 

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To answer the "do some coaches have 240 VAC appliances?"  VERY, VERY rare.  Just as at your house, most all appliances use only one hot, so they are 120 VAC.  But water heaters, some stoves, etc can be 240 VAC on larger coaches.  Again, no different than in a house.

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On 6/15/2016 at 10:19 PM, kaypsmith said:

Nathan, one thing to remember is that the circuit box in a coach is treated as a daughter box to the first, ie. earth ground is not bonded to neutral. The CG pedestal is where that must occur.

Good point Kay,

Nathan- The final test before connecting the coach to shore power might be, reading the resistance between the neutral pin and the Ground pins of the shore power cable plug. No short or resistance is good, No short between L-1 or L-2 and ground, with the main breakers open, with the mains closed and the feeder breakers open you should get the same reading. If not what is getting power / causing the resistance ?

Then turn on and off each breaker you might read resistance if something is connected to that circuit, so check all the sockets for item plugged in.

Before connecting to shore power open all the breakers, close each main one at a time. No pop, start closing each circuit breaker no issues. Repeat the process with the generator running. Then turn on the inverter and check that the circuits you have chosen to be powered check out OK.

That should indicate everything is OK, The inverter/ charger should operate off the generator the same as when connected to shore  power.

Rich.

 

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A lot of the RV generators have 120 V 30 amp breaker, and another 120 V 20 and sometimes 25 amp breaker. If you try to read L1 to L2, there will be no reading, but L1 to neutral, or ground will read 120, and L2 to ground will also read 120. Both sides are in phase with each other, hence the reading because the generator is only a 120 volt generator. These guys are usually rated 5000 or 5500 watts. One other thing about inverters, two 120 volt inverters does not equal 220/240 volts across L1 and L2, they will produce 110/120 each and can not produce 240 together for running 240 volt appliances. You can however purchase a single inverter that will produce 240 volts, most of these units require 24 or 48 volts  DC battery banks.

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