T
trainee
hi all, got 303 exam tomorrow and not feeling confident at all. We have not practised at all in the workshop, if we did practice there was no lecturer to tell us whether or not were doing things correctly, therefore i have no clue what so ever. only thing we have been told is there will total of 14 faults. 1 fault at a time.
i got a couple of questions if anyone can help.
1] I dont know what form were filling in. will we be using minor work certificate?
2] will be carrying out only dead test or will there be live test as well?
3] does missing identification count as a fault???? (silly question but want to make sure - functionality will not be affected by missing identification)
and main question (insulation resistance - interpreting value - crush injury readings etc)
4] interpreting result values. this is the main part im struggling with due to lack of guidance from lecturers.
IR - 500 Volts - 0.00 megohm = dead short (basically touching conductors) low resistance short??? right????????????
high resistance short is something like crush injury??? reducing CSA thus reducing current & increasing resistance. right?????????? what value/reading would this be?????
Table 61 bs7671 p191 state anything > 1megohm for 500V. H&S minimum for 500V = > 2 megohm
so say i get 22megohm, is that result fine???????? according to H&S and bs7671 fine. but surely that cannot be acceptable on the test rig. what value is high resistance short value?????
how do i know if theres a loose connection? what reading should i be getting??
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continuity i think is easy. either a connection or not. right? long lead method everything and / or line conductor in met and then test from equipment. and ring end to end then crossover using connector block.
-------------------
i think i know what to do, but theres still doubt in my mind. mainly struggling with insulation resistance.
if anyone can help, much appreciated.
Regards
i got a couple of questions if anyone can help.
1] I dont know what form were filling in. will we be using minor work certificate?
2] will be carrying out only dead test or will there be live test as well?
3] does missing identification count as a fault???? (silly question but want to make sure - functionality will not be affected by missing identification)
and main question (insulation resistance - interpreting value - crush injury readings etc)
4] interpreting result values. this is the main part im struggling with due to lack of guidance from lecturers.
IR - 500 Volts - 0.00 megohm = dead short (basically touching conductors) low resistance short??? right????????????
high resistance short is something like crush injury??? reducing CSA thus reducing current & increasing resistance. right?????????? what value/reading would this be?????
Table 61 bs7671 p191 state anything > 1megohm for 500V. H&S minimum for 500V = > 2 megohm
so say i get 22megohm, is that result fine???????? according to H&S and bs7671 fine. but surely that cannot be acceptable on the test rig. what value is high resistance short value?????
how do i know if theres a loose connection? what reading should i be getting??
------------------
continuity i think is easy. either a connection or not. right? long lead method everything and / or line conductor in met and then test from equipment. and ring end to end then crossover using connector block.
-------------------
i think i know what to do, but theres still doubt in my mind. mainly struggling with insulation resistance.
if anyone can help, much appreciated.
Regards
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