Hi all.
I'm a member of a FB group for people trained through a particular training provider. Recently someone posted a query for testing for electrical separation for shaver sockets, and my ex trainer responded with the following method (cut n paste verbatim):
you need to confirm separation of the transformer in the unit itself, and then segregation of the circuit supporting the shaver from the rest of the circuits of the install. to test the shaver unit before install on the bench, lift off the cover from the terminals( this will be slightly different for each manufacturer) and link line to neutral on the low voltage side with a small cable link. then using the insulation resistance setting on 500v test for 60 seconds from primary side to secondary( brown probe on primary and green probe on secondary) . to test the segregation take the L,N and CPC of the circuit out of the board and clip them together with jumper leads, crocodile clip the brown probe on at 500v to the jumper leads and with green probe test to the other circuit terminals at the breaker, earth bar and neutral bar, the result should be an open circuit reading above 1Mohm to pass.
My problem with the above in bold, is that any parallel paths (eg sup bonding, circuits sharing the same metallic enclosure etc) between the CPC of the circuit being tested for segregation, and the earth bar will give low IR/continuity. Perfectly healthy and normal, but a fail according to the above method.
I am now locked in an argument with my ex trainer. I've tried explaining every way I can, including diagrams, to show how it doesn't work, but he is insistent that it does, so insistent that I'm starting to wonder if there's something I'm missing. I would appreciate it if the good members of the forum would put me straight on this.
I'm a member of a FB group for people trained through a particular training provider. Recently someone posted a query for testing for electrical separation for shaver sockets, and my ex trainer responded with the following method (cut n paste verbatim):
you need to confirm separation of the transformer in the unit itself, and then segregation of the circuit supporting the shaver from the rest of the circuits of the install. to test the shaver unit before install on the bench, lift off the cover from the terminals( this will be slightly different for each manufacturer) and link line to neutral on the low voltage side with a small cable link. then using the insulation resistance setting on 500v test for 60 seconds from primary side to secondary( brown probe on primary and green probe on secondary) . to test the segregation take the L,N and CPC of the circuit out of the board and clip them together with jumper leads, crocodile clip the brown probe on at 500v to the jumper leads and with green probe test to the other circuit terminals at the breaker, earth bar and neutral bar, the result should be an open circuit reading above 1Mohm to pass.
My problem with the above in bold, is that any parallel paths (eg sup bonding, circuits sharing the same metallic enclosure etc) between the CPC of the circuit being tested for segregation, and the earth bar will give low IR/continuity. Perfectly healthy and normal, but a fail according to the above method.
I am now locked in an argument with my ex trainer. I've tried explaining every way I can, including diagrams, to show how it doesn't work, but he is insistent that it does, so insistent that I'm starting to wonder if there's something I'm missing. I would appreciate it if the good members of the forum would put me straight on this.
