I read a similar post which prompted a coworker and I to get into a discussion and I thought it would be a good topic to bring up here. This is a real world application that I saw pass inspection even though I thought it shouldn't.
A detached garage is being fed from the main panel in the house. There is a 100A feeder breaker in the main panel protecting the feed to the garage. The garage feeder is underground and in conduit. The feed enters through the concrete floor of the garage on the wall nearest the house. At that location is a NON fused disconnect rated at 200A. The feed then goes back under the concrete, across the garage and back up through the concrete at the far wall. At that location is a MLO load center. If I remember correctly the home owner set it up that way so the load center could be in one location but the disconnect located near the man door.
I say the MLO panel needs to be a main breaker due to the fact that the feed enters the building at the load center. This because the NEC considers the conduit under the concrete to be _outside_ the structure.
I also say the non fused disconnect needs to be a fused disconnect because it's essentially feeding another set of feeder conductors. I don't see the difference between whether it's a disconnect, or a main breaker load center feeding multiple subpanels. If it were a main breaker load center, each subpanel fed off that panel would require a breaker for that feeder.
Anyway, it may have passed inspection and in the past but now there's the question of what's right, if we run into something similar in the future. That and there's a case of beer wagered on who's more right....
View attachment 5870
Brian
A detached garage is being fed from the main panel in the house. There is a 100A feeder breaker in the main panel protecting the feed to the garage. The garage feeder is underground and in conduit. The feed enters through the concrete floor of the garage on the wall nearest the house. At that location is a NON fused disconnect rated at 200A. The feed then goes back under the concrete, across the garage and back up through the concrete at the far wall. At that location is a MLO load center. If I remember correctly the home owner set it up that way so the load center could be in one location but the disconnect located near the man door.
I say the MLO panel needs to be a main breaker due to the fact that the feed enters the building at the load center. This because the NEC considers the conduit under the concrete to be _outside_ the structure.
I also say the non fused disconnect needs to be a fused disconnect because it's essentially feeding another set of feeder conductors. I don't see the difference between whether it's a disconnect, or a main breaker load center feeding multiple subpanels. If it were a main breaker load center, each subpanel fed off that panel would require a breaker for that feeder.
Anyway, it may have passed inspection and in the past but now there's the question of what's right, if we run into something similar in the future. That and there's a case of beer wagered on who's more right....
View attachment 5870
Brian
enough to handle the load (again the SUSE issue aside; change it if it bugs somebody), and located at the first entrance of the feeders to the building. Do they go outside again? No matter. They are on the load side of a disco, and they have appropriate OCP. Break out the beer.