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  • Reverse wired Powercon connectors?

    So the "On" light on one of our FBT monitors went off the other night when my helper moved the still-plugged in monitor four feet back to it's normal position on stage. When I pointed that out he then proceeded to disconnect the power cable and noticed that the Powercon "True1" connector was loose in relation to the cable and in an attempt to show me twisted it back and forth almost 180 degrees. Before I could react the inevitable spark tripped the stage breaker causing him to pretty well pull the connector off the cable. Sigh, OK, give it to me and I'll take it home and see if its repairable.

    At home I see no apparent damage to the connector so I trim the cable and bring up the Neutrik web site to confirm specifics on making the connections. Pretty straightforward, green wire to ground, white wire to the lug labeled "N", and black to the lug labeled "L". Got it. Put it back together, take it back to the venue and just for superstitious reasons take my volt meter and compare it to one of power cables on one of the other monitors. What? The cables for all of the three other monitors appear to have the neutral and hot connections switched. Did I make a mistake? So I pull one of the "good" connectors apart and sure enough it has white wire connected to "L"oad and black wire to "N"neutral. Hmmm. Now even with my limited background in EE related things I know that with AC many/most/(all?) "appliances" can function just fine with hot and neutral on either connection but am I confident enough of that to connect my "correctly wired" power cable to a $1,500 monitor? Nope! Took the cable back home and wired it to the FBT (backward?) standard. Plugged it in and it worked fine. OK, all good, no harm, no foul, but...

    We intend to use these monitors on our outdoor stage this summer (weather permitting) and so are intending to order four additional power cables so we don't have to move cables as well as monitors back and forth. So my question is: If these new cables come in wired to the Neutrik (correct?) standard, as I assume they will, should I take them apart and reverse the wiring to the FTB standard or is that a waste of time? Has anyone every "seen" this reverse wiring before? Thanks in advance for any guidance.
    ...dave

  • #2
    I ALWAYS like to follow the standards when it comes to electricity.
    -------------------------------------------------------------------------------------------------------------------------------------------------------------------
    Former product development engineer: Genz Benz, a KMC Music/FMIC/JAM Industries Company, continuing factory level product support and service for Genz Benz

    Currently product development engineer: Mesa Boogie

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    • #3
      Originally posted by agedhorse View Post
      I ALWAYS like to follow the standards when it comes to electricity.
      ...indeed sir, as I certainly assumed would be your perspective. So maybe let me ask the question in a different way: As an amp designer/developer can you envision a potential circuit design whereby switching the hot and neutral leads entering the amp could/would cause a problem? Or, maybe stated more simply yet, would you personally have just connected the "correctly wired" power cable with confidence that it would work correctly and not released the magic smoke?
      ...dave

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      • #4
        Pragmatic non-EE POV: any powered speaker designer who builds their speaker so that a wrongly-polarized power plug can let the magic smoke out will be quickly out of business. Bars with mis-wired outlets are not exactly rare.

        If your power cord goes directly into the primary winding of a double-insulated transformer, I can't see there being any kind of issue, safety or otherwise. But I would be happy to be educated differently. And I have *no idea* how typical SMPSs are built.

        Wes
        Do daemons dream of electric sleep()?

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        • #5
          Did those power cables come with the monitors or are they from where??? Is your helpers nick "Sparky"?

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          • #6
            Originally posted by Pro Sound Guy View Post
            Did those power cables come with the monitors or are they from where??? Is your helpers nick "Sparky"?
            Cables came with the monitors. It might be from now on !
            ...dave

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            • #7
              One thing that is important with regard to polarity is that some EMC mitigation measures might favor asymmetrical filter measures, another is that safety agency listing (generally) requires any fusing and switching to be in the hot line, though there are ways around this depending on the listing class.
              -------------------------------------------------------------------------------------------------------------------------------------------------------------------
              Former product development engineer: Genz Benz, a KMC Music/FMIC/JAM Industries Company, continuing factory level product support and service for Genz Benz

              Currently product development engineer: Mesa Boogie

              Comment


              • #8
                I just wanted to mention that it's possible to not follow the wire color convention and still have the correct wiring. In other words, if the white wire was used for hot at both ends of the cable, the voltage will still be on the intended terminal of the power input. I would check the other 3 cables to see if this is the case.

                Either way, I would let the manufacturer know that either the cable was made with hot and neutral reversed or they are not following the color code convention.

                Don

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                • #9
                  The color code convention is part of the UL and CB Scheme listing procedure, if it's wrong then somebody needs to know!
                  -------------------------------------------------------------------------------------------------------------------------------------------------------------------
                  Former product development engineer: Genz Benz, a KMC Music/FMIC/JAM Industries Company, continuing factory level product support and service for Genz Benz

                  Currently product development engineer: Mesa Boogie

                  Comment


                  • #10
                    The "other" end of the cable is a molded-on Edison plug and I did confirm that the black lead at the True1 end is hot when the Edison is plugged into a standard outlet.

                    I now wonder if the fact (I left out in my OP thinking it was extraneous) that the monitor would not work afterward even with one of the other "good" cables is related to a short in the loosened connector that bypassed some intended built in protection due to the polarity being reversed in the supply line? Hmmm... Time to contact the supplier/manufacturer me thinks.

                    ...dave
                    ...dave

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                    • #11
                      Agreed. I'd contact the manufacturer. After verifying their design isn't intended to work with mis-wired cabling (My best guess is the cables are bought from an outside supplier and they had no idea). Make the polarity correct on all four cables and be on your merry way. In the process you might be saving the manufacturer a lawsuit somewhere down the line by being a god Samaritan.
                      J.R. Previously jrble

                      See my Dog Of The Hair studio at: http://www.dogoth.com/studio/

                      Quote from someone: Flat response? Get out the jack and change the tire.
                      If you think "power is knowledge", you have it backwards.

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