Cummins Onan 5500

[rocco52]

I am going to install a Cummins Onan 5500. I noticed that there are multiple variations besides the normal LP or Gas and wanted some help with this. All models are rated the same but have different setups. One has two 30 amp breakers. One has a 30 amp plus a 20 amp breaker and one has two 30 amp breakers plus a 20 amp breaker. They show the same output max amps and watts. My trailer has two AC units. Which of these units should I buy?

[pdavitt]

Since you mention two Air Conditioners, I assume you have a 50A 120/240V Split Phase shore power service. If so, it gets a little more complicated. The Onan 5500 comes in two voltage output configurations, a 120V Single Phase and a 120/240V Split Phase. If you get the split phase and wire it in identically to your shore power you will have the same circuit availability as you do on shore power, just at a reduced amperage (approximately 25A instead of 50A).

I would discuss your options with a RV or Marine electrician to determine which is the best way to go.

Pat

[rocco52]

Thanks for the reply. It is interesting that the specifications for all 6 of the QG5500 series list Max output at 45.8 amps (at 500') and the ability to start two 15000 BTU RV AC units at the same time. I have a 15 and a 13.5. This is why it is so confusing to me.

[pdavitt]

Originally Posted by rocco52

Thanks for the reply. It is interesting that the specifications for all 6 of the QG5500 series list Max output at 45.8 amps (at 500') and the ability to start two 15000 BTU RV AC units at the same time. I have a 15 and a 13.5. This is why it is so confusing to me.

Yes it can be confusing. Your 50A shore power actually supplies 100A @ 120V. The 50A rating is at 240V. Either way the shore power is outputting 12,000 VoltAmps of Power. The 5500 generator is rated at 5,500 VoltAmps, so it is providing a little less than half of what your shore power provides.

To make it even more confusing your trailer has two AC branch panels wired approximately as shown below. This is why I suggested you contact an RV or Marine electrician.
Pat

[rocco52]

I am having my RV dealer do the install. When I brought up the different units their Service Manager said that the unit with one 30 amp breaker and one 20 amp breaker was the one that they normally installed and had no issues or complaints over the years. I will revisit that issue with him. Thank you for the information!