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Dual Roof Air Conditioning Electrical Wiring
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I own a 1976 27' gasoline P30 Barth with two roof mounted air conditioners. I can operate both of them if I use the generator, but only one when I am on shore power because I am wired for only 35 amps. I want to operate both air conditioners off of shore power and I once saw an ad in a magazine for schematics to do this conversion. Can anyone remember who to contact to purchase those schematics. It allows you to ad a second 115v cable to the shore power outlet or gang the two into a 50 amp plug. I do not want to use the switching system sold by Camping World as it is not based on a sound system as I understand it. Any ideas on what has to be done, added, switched? Have you seen the ad in a classified column? Also, I would pay for copying a manual that is close to my year. Anyone have such a manual?
Thanks, Joel
Posts: 3 | Location: San Antonio, Texas | Member Since: 09-06-2001Reply With QuoteReport This Post
"First Year of Inception" Membership Club
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This data was sent to me from a guy on another great RV website.....

Dave, attached file shows the wiring for the back A/C break out. I used a locking twist lock plug. Make sure that the rear A/C is protected with a circuit breaker. Also found that Fleetwood had wired the microwave to the rear A/C circuit so we had to shut down the rear air to run the microwave.
Ken Wilson
Conroe, Texas


[This message has been edited by davebowers (edited September 07, 2001).]
Posts: 1985 | Location: Eden Prairie, MN 55346 USA | Member Since: 01-01-2001Reply With QuoteReport This Post
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The following is a very long answer to your question sent by

A/C and 30 Amp

The genset has two circuits, a 30 amp that is wired to the main circuit panel which also powers one of the A/C units, usually the front. The other 20 amp circuit is wired direct for the other A/C unit. The 30 amp genset is usually wired through a time delay and a relay that selects between campground power and genset power. the time delay allows the genset to come up to operating speed before it powers anything. What you are getting with the genset is 50 amps through the two circuits. To be able to run both A/C units when hooked to the campground power will require either both a 30 amp and 20 amp source, or a 50 amp source. I think the best way to wire for campground power is to put a relay in that is powered by 20 amp genset or by a new 20 amp source from the campground. The relay will cost about $40 - $50 and you will need to wire in a new circuit that can be plugged in at the campground. I would wire another 30 amp chord that connects to the new relay just like the existing power line is wired. The relay that is in the unit now, is a double pole - double throw which in default mode provides power from the campground. When the genset is on it powers the realy to select the other side of the relay which is the genset. You need to wire the new relay the same way. You might also want to provide a time delay for the new circuit when on genset power by providing the new relays coil power from the existing 30 amp genset source. That way you don't need to get another time delay in the 20 amp genset circuit. So when you power up the genset both relays get energized and if you have the new circuit plugged in the second A/C will operate. This all assumes that the campground power panel that you plug into has capacity for 50 amps either by having separate 30 amp and 20 amp circuits or a 50 amp that you can split off of. You can wire a 50 amp adapter that can be split off for two circuits of 30 amp and 20 amp that you could plug the two rv chords into. The thing that you have to be careful of is that the 50 amp breaker won't trip unless the short circuit pulls 50 amps., which neither chord will be able to handle, so the risk is that you melt one of the chords. This will only happen if the short is between the circuit panel in the rv and the campground panel, not likely but can happen. That is why I like the two chord approach, you aren't compromising the circuit protection already built in. 30 amp chord will cost you about $1.50 a foot plus the cost of the connector which is about $10. I like the 30 amp chord because it is number 10 wire which will reduce resistance and is protected for the campground environment.
Posts: 1985 | Location: Eden Prairie, MN 55346 USA | Member Since: 01-01-2001Reply With QuoteReport This Post
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