200-Amp Service Rate Whole House Transfer Switch

Simply stated, in order to provide standby power to both 150 amp panels two ATS units are required since the "sub-panels" you reference are likely the service panels and both serve as the "Service Disconnecting Means". If so, then your service rating is 300 amps (2 x 150) and a 200 Amp rated ATS is not large enough for a 300 Amp service. Even if the above is not the case, explaining how to wire this 200 Amp ATS to two 150 amp panels is too complex to explain here. Beyond that are two other issues. When this switch is installed the feeders between this ATS and the existing panel must be replaced, and the neutral conductors and the equipment grounding conductors must be terminated differently. Since you don't understand any of this, based on the nature of your question, you would be far better off hiring an experienced and qualified electrician. Here's hoping that you did!

The height, width and depth of this transfer switch are 30-1/4" by 14" by 6-5/8".

Yep

Yes it can, conditionally. As long as the existing 200A SE rated switch is actually a service disconnect switch, meaning it is the only switch that disconnects the electrical service from the premises. If the existing "Service Disconnecting Means" is a 200A MB (Main Breaker) in the single distribution panel then that is not a problem, as that breaker then becomes just a redundant disconnect, but it is no longer the Service Disconnect, since this Generac ATS (Automatic Transfer Switch) becomes the "Service Disconnecting Means". However -- when this Generac ATS is installed, as noted above it becomes the "Service Disconnecting Means", meaning it is now the Service Equipment, overriding the MB panel. Now all the neutrals and EGCs (Equipment Grounding Conductors) MUST be separated and terminated on independent terminal bars. All the neutrals terminate on the isolated neutral bar, meaning it is not electrically conductive to the panel's metal enclosure. All the EGCs terminate on a separate terminal bar screwed directly to and electrically conductive with the metal enclosure. And, the original bonding screw or bonding strap MUST be disconnected from the neutral bar. The bonding screw and or the bonding strap are sometimes green-colored for identification. This is required when the panel is not the service disconnect equipment, so that the neutrals and grounds are completely independent of each other at the panel. Most homeowners, and some electricians, miss this very important distinction, which briefly stated is relevant to personal safety by means of reducing the risk of electrical shock, or worse.

Yes, model # RXSW200A3 is an automatic transfer switch.

Yes, this unit is compatible with multiple generators.

The smart ac management module (SACM) that controls switch functions is designed to work with the controller in the generator. It sends out 240vac from the incoming utility power. The generator controller logic monitors this signal and responds when it goes off initiating the startup/run sequence. Once the generator is providing power to the switch it sends a transfer command to the switch by switching the line #23 to 12vdc ground activating the transfer relay in the SACM. An interface would have to be engineered to provide a 2 wire dry contact for the generator and the transfer command to the switch if not using the expected controllers.

According to NEC code, the automatic transfer switch amperage must match the amperage of the utility coming into your home for whole home backup applications. We recommend verifying that you do, in fact, have 200 Amp utility service, which would match the transfer switch.

We do recommend using our transfer switches with Generac generators, but the Generac model #RXSW200A3 is designed for use with single phase generators that utilize an Evolution or Nexus Controller. For more information we recommend working with an authorized Generac dealer. If you need assistance finding a local dealer, we recommend using our dealer locator found here: http://www.generac.com/dealer-locator

Our transfer switches do not have a maximum wattage rating. They do have a Withstand Rating in amps, and for this specific model it is 22,000 amps. Meaning the transfer switch is able to withstand any amperage up to 22,000 amps.