Why do we have 3-phase ratings available ?

3-phase power is used over 1-phase power primarily for weight reduction/saving and efficiency in smoother running accessories. The 3-phase circuits will deliver both 208 VAC as well as 115 VAC with more torqueing power. Delta Systems are used almost exclusively aboard military naval vessels. This is done because there is no ground in the system. This method is used to protect personnel on board. Should any phase come in contact with ground, the person shorting himself to any one of the three phases can never short to ground and, therefore, will never be electrocuted.