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Thread: 430.36 and 430.37

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    430.36 and 430.37

    I have a very old combination starter (1950's?) that has only two overload devices installed in phases A and C. The starter is using a 3-phase fused switch (vs MCP) for motor branch protection. The fuses are for short circuit only. Is this a violation of 430.36?

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    It would seem that you do in fact have a fuse installed in each ungrounded conductor, but, they are not being used for the overload protection.

    The 2 overloads in the starter are serving that purpose.

    If 1 or the other Overloads amperage gets exceeded it will trip out the entire overload and disconnect the motor, or, at least it should.


    JAP>

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    Though you may need to look at 430.7 and it's table to see if you have enough overloads in place to serve the purpose.


    JAP>

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    Quote Originally Posted by jap View Post
    Though you may need to look at 430.7 and it's table to see if you have enough overloads in place to serve the purpose.


    JAP>

    I've done a little more research; it seems prior to 1971 NEC, two overloads were acceptable. Since then, a concern over 'single-phasing' has led to requirement of OL's in each phase.

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