I was looking at an exisitng one-line diagram and noticed sometihing [unrelated to the project at hand but got me thinking], there is an automatic transfer swtich connected to a set of transfomrer secondary conductors? It was my understatding that according to article 240 that the conductors have to terminate in an OCPD, the transfer switch is not service entrance rated and utilizes a contactor based design without the use of breakers or fuses, the load side of the transfer switch terminates to a panelboard with a main switch and fuse unit however there is no protection on the transfer switch besides the priamry OCPD, the xfmr. is a standard dela-wye and requries a secondary disconnect does the transfer switch meet these requriements when there is no SE rating or breakers? I assume you would either need a seconary disc. or an SE rated transfer switch?
Xfmr. Secondary Conductors
- Thread starter Mike01
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Take a look at 240.21(C)(2). If the secondary conductors are not over 10 ft, an argument could be made that they terminate in a device. The other tap rules seem to indicate termination in an OCP device, but the 10 ft simply states device.
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