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Hi, I work in a very large factory and we are now paying more attention to Inspection & Testing than before. Because of the arrangement of the distribution systems I would like to know what the ZE would be called (Zdb,etc) at the very many dist boards we have, and how it should be measured ?
These dist boards are supplied from 11kv/430v package transformers (there are approx 20 of these on site) and in most cases a separate copper protective conductor is run also.
It would be inappropriate to disconnect the earthing conductor, as the dist board could not be isolated for the test.
Final circuits are being added to these DB,s and some of these go into hazardous areas where a ZS live test could not be done, so has to be calculated.
Rather long winded I know but would the standard ZE be done at the DB (without the earthing conductor being disconnected) and called Zdb ?
Also there will be many parallel earthing paths affecting this reading.
These dist boards are supplied from 11kv/430v package transformers (there are approx 20 of these on site) and in most cases a separate copper protective conductor is run also.
It would be inappropriate to disconnect the earthing conductor, as the dist board could not be isolated for the test.
Final circuits are being added to these DB,s and some of these go into hazardous areas where a ZS live test could not be done, so has to be calculated.
Rather long winded I know but would the standard ZE be done at the DB (without the earthing conductor being disconnected) and called Zdb ?
Also there will be many parallel earthing paths affecting this reading.
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