home Generator switching re electric boiler

We are looking at installing a backup generator in a home that has a 400 A service and a very large electric boiler system. I understand that a 400A transfer switch would be required to switch the panel from regular electric feed to generated power. A 20 KW self starting generator system would easily handle everything with the exception of the electric boiler. Is there a way to have the boiler switch off when running on generated power, ie some sort of a cut out switch? It is a seasonal home and not likely that someone would be there and could just turn the thermostat down to stop boiler from coming on. It would seem there should be a way to do this without adding sub panels as we have very little space available to add another panel.
Thank you, John

 

Generac's 400amp service entrance switch has load shedding built in, 2 thermostat connections plus 4 connections for up to 50amp (small) load control modules. Kohler has the same capability using a separate panel 18.4" x 15.4" x 5.3".

The Generac and Kohler service entrance switches are NEMA 3R and can be mounted outside, freeing up interior space.

 

You need a circuit fed from upstream of the transfer switch (is that what the load shedding feature consists of?)

Such a circuit might be used to light up an indicator to tell you when utility power is on (again), or in this case to operate a relay (load control module? or contactor) downstream of the boiler's breaker to enable/disable the boiler.

 

No. load shedding is a feature of whole home switches that sit between your meter and main panel. Load shedding is done by opening relays on circuits when excessive load is sensed. There are variations in the programming across different brands, but the switch (and features) should be from the same brand as the generator.

 

Good reply pat.

In working with generators all the time we get to see the different transfer switches. The Generac one has better load shedding options. The Kohler, although a better switch, requires that expensive load shedding module unit(GM77) with the relays.

 

Hi Guys
Thank you for the replies. I will forward this information to my electrician. This should lead us to a solution
John