Transfer switch for automatically switching neutrals for one or more loads between two electrical sources of power

摘要

A method and system for selectively controlling the supply of electrical power to an electrical panel that is capable of receiving electrical power from more than one power source, such as a utility power supply and an auxiliary power supply, e.g., an electrical generator, prevents the neutral conductor of the electrical panel from being connected to one power supply when the hot conductors of the electrical panel are connected to another power supply.

主权项

1. An apparatus connectable to a transfer switch panel for automatically connecting neutrals of one or more loads to either a neutral of a first power source or a neutral of an alternate power source, wherein the transfer switch panel includes a transfer switch having a first input configured to receive power from one of a first hot conductor and a second hot conductor from the first power source, a second input configured to receive power from one of a first hot conductor and a second hot conductor from the alternate power source, and an output configured to conduct power from the first power source when the output is connected to the first input and to conduct power from the second power source when the output is connected to the second input, the apparatus comprising:
a load side neutral conductor that connects to the neutrals of the one or more loads; a first neutral conductor that connects to the neutral of the first power source; a second neutral conductor that connects to the neutral of the alternate power source; a first electrical conductor that connects to either the first hot conductor or the second hot conductor from the first power source that is not connected to the first input of the transfer switch; a second electrical conductor that connects to the output of the transfer switch; a third electrical conductor that connects to either the first hot conductor or the second hot conductor from the alternate power source that is not connected to the second input of the transfer switch; and a switch that connects the load side neutral conductor to the first neutral conductor when a voltage potential between the first electrical conductor and the second electrical conductor is greater than a voltage potential between the second electrical conductor and the third electrical conductor, and connects the load side neutral conductor to the second neutral conductor when the voltage potential between the second electrical conductor and the third electrical conductor is greater than the voltage potential between the first electrical conductor and the second electrical conductor.