Additional Service Disconnect

[Canton]

Hello All,

I have a large residence that is having a huge HVAC renovation. The HVAC contractor has hired me to install a new service panel for all the new HVAC loads. There is not enough space in the existing (2) 200 amp panels. I want to install a 150 amp Main breaker panel to support all the new HVAC loads. The house has an existing 400 amp service (really 350 amp) being fed with copper 350 mcm, which are then tapped to (2) 200 amp main breaker panels.

My question is: Will I have a problem with the AHJ at inspection with a total Main Breaker amperage with 200+200+150=450amps on a 350 amp service? :? The calculated load is below 350 amps. 10-20 years down the road I could see the potential of all the panels one day being filled, don't know if there would be an issue with the AHJ.

Thanks

 

[jumper]

As long as the current calculated load does not exceed the ampacity of the service conductors or meter, and the taps are are properly sized and installed correctly-you are compliant I believe.

And the service disconnects are grouped together.

 

[kwired]

A agree with Jumper.


with multiple disconnecting means, service conductors only need to be able to carry the total calculated load, and not necessarily the number you get if you add up the amperage of the overcurrent devices. If you are close it is a design decision to run larger service conductors, but not a requirement until that load is actually there.