How Does the Automatic Transfer Switch Detect Shore Power on the Rich Solar NOVA 3K12 Inverter?

Updated 10/21/2026 | Published 10/15/2026

Question:

What amperage is needed to supply to the automatic transfer switch on the Rich Solar Nova Switch so that it will be able to determine whether to switch to inverter power or shore power?

asked by: Jerry

Expert Reply:

Hello Jerry,

Welcome to etrailer, I'm glad you found us!

Thanks for writing in.

I see where your brain is going with this, but that is not quite how the automatic transfer switch works on the Rich Solar NOVA 3K12 Inverter # RS79VR.

Instead of monitoring amperage, the transfer switch monitors the incoming AC voltage. It is designed for 120V AC shore power, and when it detects voltage within its operating range of 80V to 140V, it automatically switches to shore power. When shore power is lost, it switches back to inverter power in less than 20 milliseconds.

The 30-amp rating is how much current the transfer switch can handle, not what it needs to detect shore power.

What kind of camper or application are you looking to install this in?

expert reply by: Kate F

Jerry

10/15/2026

I'm going to be running the Inverter in a 5th wheel RV. I guess what I need to know is, if I run a 10/2 romex cable from a 120v 15 amp circuit, will that produce enough of a current for the ATS to detect that there is 120 AC or does it need to come from a 120V 30 amp circuit?

Mike

10/16/2026

@Jerry I got the same one and just installed it on ours. Using the 10/2 and 15 you mentioned will be plenty. Ours switches over to DC power as soon as I unplug us.

Jerry

10/16/2026

@Mike Thank You!

Kate F.

10/21/2026

@Jerry Yes, your 120V 15-amp circuit will work just fine. The automatic transfer switch on the Rich Solar NOVA 3K12 # RS79VR detects incoming AC voltage, so it does not require a 30-amp circuit to switch over to shore power. Your 10/2 Romex will work for that setup as well. Just keep in mind that when running on shore power, you will be limited to the 15 amps available from that circuit, even though the transfer switch itself is rated for 30 amps.