Where does the second breaker go when used. Doesn't look like the cover has any place for a second one but maybe there is details we can't see or modifications needed that are not obvious in this image?
This is the existing setup. The discussion is about the possibility of changing this section with one main and replacing it with incoming service section that has 2 mains (400A and 200A)
Seems much cheaper and easier to just add a new 200 and keep the 400 as is.
So just changing the main power section of a modular meter system it sounds like?
And like already said that is perfectly fine to make your service entrance 600 amp and it sounds like that is the direction you want to go in
It actually depends on a load calculation.
In what way does it make a difference, unless your thinking the calculations for the existing 400 amp is out. Of compliance
So in other words it makes no difference to the NEC which way it is done
No, it does make a difference. We don't know if there are service conductors between the service point and the place the OP wanted to put a wireway and tap. If there are, then whether those conductors can be reused depends on the total load calculation.
I agree in principle what your saying. The OP said he was going to add a new set of 3/0 to what was suppling the 400 amp service. That implies that the existing service is two sets of 3/0 assuming the OP understands he would have to parallel these three sets together.
Unless the 400 amp service has no actual history the nec is no longer concerned with the calculated load of the 400 amp service.
Yes there is . Where service conductors feed multiple service disconnects, the conductors are sized to the load. Where service conductors feed a single disconnect, the conductors must also be sized to the ocpd they are feeding. Another difference is you likely get more diversity, in practice and in the calcs, when you have a single set of conductors serving everything.
I didn't say there was no difference. I said in how the calculated load is addressed
Yes it's different. If an additional parallel was added to the 400, the entire load, including any new load, would be calculated. If a new set were added, just the new load that set is serving would be considered.
There is no diferance in what your saying.
I suggest you reread post #35. Sure is probably a relatively small difference for the size services we are talking about but nonetheless there is a difference
I think the point is that if one looked at demand history and it were low enough it may be possible to add the new load to the existing 400 amps of service conductor, keep existing 400 amp main and add the additional 200 amp main.
