Electrical power distribution systems with a bypass unit that couples to a load and electrically engages one of two alternate units for powering the load and related methods

A bypass unit for a motor control center including a structure defining a plurality of compartments having first and second units installed therein, the bypass unit comprising:

• a housing configured to be insertable into and removable from a compartment of the plurality of compartments;
• and
• a bypass circuit including a power transfer switch in or on the housing, wherein the power transfer switch comprises a six-pole isolation switch configured to selectively couple the first unit to a load or the second unit to the load, wherein the six-pole isolation switch includes a first set of three switch contacts of the six-pole isolation switch configured to couple to the first unit and a second set of three switch contacts configured to couple to the second unit.