An electrical submerged pump suitable for pumping a pumped product while isolating the pumped product from motor lubrication contained in a motor housing within the ESP, said isolating being without implementation of a bellows, diaphragm, or bladder, the ESP comprising: a pump comprising a pump impeller contained within a pump housing; an electrical motor; a motor housing surrounding the electrical motor, the motor housing containing a motor lubricant, a lower region of the motor housing extending below the electrical motor; a rotatable shaft extending from the electrical motor to the pump; a seal configured to prevent a pumped product from leaking into the motor housing along the rotatable shaft; a seal chamber surrounding the seal; an outer barrier chamber located below the motor housing; an inner barrier chamber nested within the outer barrier chamber; an ESP housing surrounding the pump, the motor housing, and the barrier chambers; a first interconnection configured to enable liquid communication between the lower region of the motor housing and a lower region of the outer barrier chamber, whereby motor lubricant entering the lower region of the outer barrier chamber through the first interconnection is caused to float to a top of the outer barrier chamber; a second interconnection configured to enable liquid communication between an upper region of the outer barrier chamber and a lower region of the inner barrier chamber; a third interconnection configured to provide liquid communication between an upper region of the inner barrier chamber and a product location within the ESP housing, the product location being filled with the pumped product; and a barrier fluid included within the outer and inner barrier chambers (200, 202), the barrier fluid being immiscible and non-reactive with the motor lubricant and the pumped product, and having a barrier fluid density that is higher than a density of the motor lubricant and a density of the pumped product. a pump comprising a pump impeller contained within a pump housing; an electrical motor; a motor housing surrounding the electrical motor, the motor housing containing a motor lubricant, a lower region of the motor housing extending below the electrical motor; a rotatable shaft extending from the electrical motor to the pump; a seal configured to prevent a pumped product from leaking into the motor housing along the rotatable shaft; a seal chamber surrounding the seal; an outer barrier chamber located below the motor housing; an inner barrier chamber nested within the outer barrier chamber; an ESP housing surrounding the pump, the motor housing, and the barrier chambers; a first interconnection configured to enable liquid communication between the lower region of the motor housing and a lower region of the outer barrier chamber, whereby motor lubricant entering the lower region of the outer barrier chamber through the first interconnection is caused to float to a top of the outer barrier chamber; a second interconnection configured to enable liquid communication between an upper region of the outer barrier chamber and a lower region of the inner barrier chamber; a third interconnection configured to provide liquid communication between an upper region of the inner barrier chamber and a product location within the ESP housing, the product location being filled with the pumped product; and a barrier fluid included within the outer and inner barrier chambers (200, 202), the barrier fluid being immiscible and non-reactive with the motor lubricant and the pumped product, and having a barrier fluid density that is higher than a density of the motor lubricant and a density of the pumped product.