303 exam rectification method on IR

[hickey]

i done my 303 practical, and ive got 1 fault im not to sure the rectification method i got was correct

i found out that the immersion heater was dropping the ir between l-e to around 0.10 ohm

remove fronts on immersion switch and the fused switch, visually check to see if there any loose connections, if none disconnect the fused switch and do a ir test between l-e at the board, if theres no fault reconnect the fused switch and redo the ir test, if theres a fault

(not to sure what to do if the fused switch say had the fault, need some help on that )


would a PIR code of 1 be correct for this as the OSG states a 2m ohm is the lowest it can have

 

[telectrix]

disconnect heater flex from FCU/D/P isolator. IR test element. if faulty, replace element.

if element tests OK, IR flex and element combined. if low IR, replace flex.

IR test from CU to FCU. if low IR. replace cable .

 

[hickey]

disconnect heater flex from FCU/D/P isolator. IR test element. if faulty, replace element.

if element tests OK, IR flex and element combined. if low IR, replace flex.

IR test from CU to FCU. if low IR. replace cable .

its the practical so there was no element in there, well as far as i know in the 302 they took it out becuase people were getting readings that they didnt understand,

im not physically allowed to take covers off so im assumin they took it out,

would this be correct then

if theres no fault reconnect the fused switch and redo the ir test, if theres a fault replace the cable between the immersion heat and the fused switch

what PIR code would you give to this ? maybe a 2 ?


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[Plonker 3]

If you can not remove any covers how can you be expected to find the fault?

 

[hickey]

If you can not remove any covers how can you be expected to find the fault?

tested with ir tester found the fault was the immersion heater as it dropped it 0.10ohm

we just need to write up how i'd get the fault back up to a suitable value on that circuit and the PIR code for it

 

[Plonker 3]

Well the only thing you could do to improve the IR result is remove any known loads from the circuit.

As it it isn't presenting any immediate danger then C2 it as it would require further investigation as to why the reading is so low.

 

[hickey]

Well the only thing you could do to improve the IR result is remove any known loads from the circuit.

As it it isn't presenting any immediate danger then C2 it as it would require further investigation as to why the reading is so low.

would this work for the method to rectify ?

remove fronts on immersion switch and the fused switch, visually check to see if there any loose connections, if none disconnect the fused switch and do a ir test between l-e at the board, if theres no fault reconnect the fused switch and redo the ir test, if theres still a fault change the cable from the immersion switch to the fused switch

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[Plonker 3]

A low IR reading won't be caused by a loose connection. It will either be the load, faulty isolator (where the insulation inside is failing) or a fault on the cable so the insulation is failing, the clue is in the name of the test.