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Thread: C1D2 Connectors

  1. #1
    Join Date
    Jun 2016
    Evansville, IN, USA

    C1D2 Connectors

    I am retrofitting and existing system with controls upgrade. The application is that I am purging & pressurizing (type Z) a panel that will have connectors on it.

    I have a connector that only has IS circuits in it. Since I'm using IS barriers, I should be able to use normal wiring methods. However after a brief search, I see that Harting sells an Intrinsically safe connector, but I can't really see much difference between it and a regular connector. Do I have to have a special connector for an intrinsically safe circuit, or can I use a regular connector?

    I also have motors that will be fed from this panel. Even though the panel is purged, I still have to use a C1D2 Plug or better because the Purge and pressure are on the inside of the panel and the connector is on the outside, correct? The purge and pressure will not cover a plug connected to the panel.

  2. #2
    Join Date
    Apr 2004
    Mission Viejo, CA
    I have read and reread the OP several times. I assume the panel's exterior location is Class I, Division 2 as implied by the Type Z purge. I further assume the exterior atmosphere has been properly classified and properly documented as required by Section 500.4(A). I assume the Type Z purge meets the requirements of NFPA 496.

    A few comments:

    • Intrinsically Safe (IS) barriers alone do not necessarily guarantee an IS circuit. [See Section 504.10(A)] That is, without a proper control drawing, it isn't a IS System.
    • I looked at the Harting connectors. They are IS [Ex i] rated because they are only suitable for use in an IEC IS application. They do not meet the NEC "Zone" requirements of Section 505.9; particularly 505.9(B) and 505.9(C)(2). Many European manufacturers still haven't learned that meeting the ATEX Directive doesn't make their product suitable for US domestic markets.
    • Depending on the actual air flows, the purged enclosure may in fact be suitable protection for the connectors/plugs. Otherwise a listed Division 2 connector/plug must be used.
    Robert B. Alexander, P.E.
    Answers based on 2014 NEC unless otherwise noted.

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