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- Feb 10, 2009
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On my recent 2399 course we were instructed to just IR test the dc main cable i.e. disconnect pv string and and inverter then IR test between +ve and inverter case (building earth) and then between -ve and inverter case.
Reading page 53 of the DTI guide this seems to be insufficient. If I'm reading this correctly for non-bonded array frames I should do the following
(i) At the inverter with array connected and dc iso closed test between -ve cable and building earth and between +ve cable and building earth (Alternatively between shorted -ve & +ve and building earth)
(ii) On roof test between string +ve cable and array frame and between string -ve and arrary frame (Alternatively between shorted string -ve & +ve and array frame)
When trying to understand things I always try to think about what it is that we are trying to achieve and when I know this I find things easier to understand.
So here I'm thinking that for shock protection we are making sure that neither the building earth nor the array frame are in contact with either the -ve or +ve dc conductors. (Although for somebody to get a dc side shock in this fault condition they would also have to be in contact with the conductor not touching earth or the frame.)
How wide of the mark am I?
Reading page 53 of the DTI guide this seems to be insufficient. If I'm reading this correctly for non-bonded array frames I should do the following
(i) At the inverter with array connected and dc iso closed test between -ve cable and building earth and between +ve cable and building earth (Alternatively between shorted -ve & +ve and building earth)
(ii) On roof test between string +ve cable and array frame and between string -ve and arrary frame (Alternatively between shorted string -ve & +ve and array frame)
When trying to understand things I always try to think about what it is that we are trying to achieve and when I know this I find things easier to understand.
So here I'm thinking that for shock protection we are making sure that neither the building earth nor the array frame are in contact with either the -ve or +ve dc conductors. (Although for somebody to get a dc side shock in this fault condition they would also have to be in contact with the conductor not touching earth or the frame.)
How wide of the mark am I?
