• Posts Tagged ‘separately derived’

    Separately Derived Systems and 4 Pole Transfer Switches – When and Why?

    by  • October 27, 2011 • Code Compliance, FAQ's, General • 0 Comments

    When reviewing emergency power system designs, I am sometimes asked about 4-pole transfer switches.  The typical question is “when should I use them?“, followed quickly by “why should I use them?“. Since each project is likely to have special circumstances that make a generic answer impossible, this article focuses instead on providing the basic sources of information that should allow you […]

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