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400 Amp Service and EG4 Grid Boss

Pilot Bob

New Member
Joined
Feb 7, 2023
Messages
55
Location
Maryland, USA
The builder said we will have a 400 Amp service into a new home with two 200 Amp panels. Will this require 2 each of the EG4 Grid Boss and a EG4 Flex Boss 21,or is it feasible that we will be able to run most loads on one of the 200 Amp panels? With 1 Flex Boss is was planning on having 22-23kw solar input, If I need 2, can I divide the solar input between the two so each can manage the loads of the panel? In my county, a ground mount system can only produce 120% of what the house uses to limit energy going to the grid. Hopefully this makes sense.

Thanks, Bob
 
What are your architects calculations for your loads?
Mine grossly over calculated for reasons that I did not understand and I ended up correcting them and getting it down to a single 200 amp panel again.
 
I don't know what most people have in their homes, but lots of the posts that I see here it looks like builders or electricians are often heavily overestimating these load requirements.

One thing to consider is that if you have enough loads to require 400 amp service, you're probably gonna need a real big solar system. 😅

But really, I'd want to do the calculations myself and double check just to be sure.
 
I would have him put in the 400 amp service if it makes him happy, but only install one 200 amp panel, and put all of your loads on that. Add an Emporia Vue or equivalent, and you will know how close you are to maxing out your system, or if you ever even get close to 200 A. You can always expand later. Have the electrician leave room to put another 200 amp panel in if you really need it, but then you can start with one grid boss and some number of flex boss 21 inverters, and expand later as required.

Note that the FlexBoss 21 is only good for 75 A, so you might need two or three of them depending on how close to your supposed 200 amp load you are. Just leave room in the installation location for extra inverters (and batteries) and you’ll be fine.

You could even put in the second 200A panel for now, and call it non-critical (grid-only) loads, to reduce the required size of your solar system.
 
No one here can answer what loads you have, but reasonable chance you don't need it. I have a 400 amp service but my peak 15 minute power usage from the electric company data for last year was 12kW before I added a 12kW car charger. Now it is 18kW over the last year, but I don't charge often. I would guess most 400 amp services are for the purpose of additional circuit breaker room rather than load.

I'm in the process of converting one of my 200 amp panels into a grid only loads panel, and the other into a backed up loads panel to be powered the inverter.
 
You guys understand it’s very easy to do the load calculation as required by the NEC. There’s multiple places online that the form is automated, you just put in what the house has
 

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