The Square D MGP36800YP is a PowerPact M unit mount breaker rated 800A, 3-pole, with an electronic trip unit and an interrupting capacity of 18 kA at 600 VAC. It comes with a padlock handle for lockout/tagout and lugs off the end for cable termination. This is a Category 01205-MG, MJ UNIT MOUNT BREAKER — a self-contained frame designed for direct mounting in switchboards or panelboards, not a DIN-rail or plug-in style.
What the 18 kA rating means for your panel
That is a moderate SCCR for a 800A frame — enough for most low-voltage distribution downstream of a 500 kVA transformer, but not enough for a high-capacity service entrance near a 2500 kVA unit. The 600 VAC rating covers 480 V and 600 V systems; on a 480 V system the interrupting rating is typically higher (check the nameplate for the 480 V value, which often runs 25 kA or 35 kA on this class of breaker).
Integration notes for the install
Padlock handle accepts up to three padlocks for group LOTO — standard for a main or feeder breaker in a panel that multiple trades work on. Lugs off the end accept aluminum or copper cable; verify the lug wire range against your conductor size before pulling. The unit mount footprint bolts directly to the panel mounting pan — no DIN rail, no subplate adapter. Torque the line and load lugs to the values stamped on the breaker label; under-torquing is the most common cause of thermal trip nuisance on an 800A frame.