[RE-wrenches] Integrating with a whole house generator

[Drake Chamberlin]

Hi William,

I should go into a little more detail about how to hook up the system 
with an inverter having both AC IN 1 & AC IN 2, with the entire 
service backed up by a generator transfer switch.

There are a couple of ways to accomplish the hookup.   With one 
method, you will need to make taps from both the grid feed and the 
generator feed ahead of their connections to the transfer switch, to 
supply the two AC IN connections.  There are some code rules that 
will need to be taken into account.

With the other method, the power can be taken from the load side of 
the transfer switch, from a breaker in either the main service or the 
transfer switch. This will require an external transfer switch on the 
wires feeding the inverter, to switch between AC 1 IN and AC 2 in, 
depending on whether the generator is running or not.

For your present application, I'd prefer SMA equipment, since there 
is only one AC input connection.  The inverter supports a control 
wire that senses when the power is coming from a generator.  The feed 
for the Sunny Islands would come directly from the load side of the 
transfer switch, without the external transfer switch.  Additionally, 
with an AC coupled SI setup, the protected loads panel would receive 
full power from the Sunny Boys when the sun is shining.

If you want further details on any of this, please contact me off the list.

Drake


At 09:42 AM 11/25/2008, you wrote:
>That is the way to do it.  The inverter controls the generator 
>automatically, based on battery voltage and / or current.  The 
>generator can be started manually whenever desired.  The inverter 
>(critical) loads will also be fed by the gen-set through the 
>internal transfer switch on the inverter, while batteries are being charged.

Drake Chamberlin
Athens Electric
OH License 44810
CO License 3773
740-448-7328
740-856-9648