Main Breaker Panel Vs Main Lug

If the panel was designed to be a main panel there would be a lug that connects the neutral ground bus to the panel.

Main breaker panel vs main lug.

If you attach to lugs in the main box then you need to have a main breaker in the sub panel. For mlo panels the incoming cables are terminated on line side lugs that are attached directly to the bus no main overcurrent device exists in the panel. If you use a main lug panel you need to have a back fed breaker as a disconnect or have no more than 6 breaker throws handles. They are sometimes installed adjacent to a main panel to provide additional circuits when the main breaker panel is full or they may be installed far away from the main panel to provide a local disconnection for circuits in a detached building garage or room addition.

A main lug only mlo panel only has main lugs and is intended to be fed by a main breaker upstream. You can convert any panel to a subpanel by simply adding a ground bus and moving all the grounds to the added bus. There are situations where a back fed circuit breaker and a retainer clip required by nec are used to convert a main lug load center to a main breaker load center. Buy a 100 amp main breaker contractors pack at a big box cheapest way to go.

If you attach in your main box to a breaker then it can serve as the protection device for the sub but doesn t have to. Main lug vs main breaker is simply a matter of whether the added panel has an integrated protection device. You can feed it with less than 100 amps sent from my rct6203w46 using tapatalk. Main lug load centers are sometimes referred to as add on.

You should only have one main panel. Since you say a section is buried i assume garage is detached. You need to remove that lug if converting to a subpanel. A main breaker panel mcb has a main breaker built into it.

Main lug units are primarily used as a distribution panel where there is a main breaker upstream in the system.