Any tips on the C&G 2330, 303 practical exam?

Joined
29 Oct 2008
Messages
41
Reaction score
1
Location
Essex
Country
United Kingdom
Hello all members of the DIY not forum.
Was wondering if anyone has done their 303 practical exam yet and if they might have any tips that they might like to share? I have got my exam coming up in a week and even though I know how to test it would be an advantage to know roughly the types of faults that may occur and the order in how to find them with the results found i.e. IR = 0MὨ (short circuit), how can you tell were the short circuit is without the visual inspection (removing the trunking lids etc and looking for the faults).
Any help would be grateful and thank you in advance to any posts.
 
Sponsored Links
Joined
3 Nov 2006
Messages
26,932
Reaction score
2,900
Location
Bedfordshire
Country
United Kingdom
Being pedantic if the IR = 0 ohms then the fault is where your probes are touching the conductors. You can work out where the short is by accurately measuring the resistance and then using the value of ohms per metre for the cable then work out the approximate distance to the short circuit.

There are more accurate methods but I doubt these are ever taught for testing purposes. ( testing as apposed to fault finding )

This method puts a current through the cable to generate a voltage drop along the cable. The ratio of voltages gives the ratio of distances and does not require highly accurate ohms readings which are seldom possible with the variations in contact between probes and conductors

 
Joined
29 Oct 2008
Messages
41
Reaction score
1
Location
Essex
Country
United Kingdom
Nice answer burnardgreen, any chance you could add an example by any chance on the formulae that you would use? Don’t think I will need this information for the exam but I am interested for understanding it personally?
 

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Sponsored Links
Top