tonights 2391 exam....(10th march 2011)

[LlandrilloSpark]

Sorry John I was with u, I put it as 30ma additional and did the 6 tests , can't be 500ma? Surely? Earth electrode was 100 ohm

 

[IQ Electrical]

I thought that the maximum operating current was worked out as 50v/Ra=in. Is RA not the resistance of the electrode, which was 100 ohms giving an answer of 500mA?????

If they were the figures given then you are correct.

Also, there would be no test at 5X I delta n

 

[jimmy_one_ball]

I thought it was well hard! For the IR test I said test between L+N together and cpc @ 250V because of the voltage sensitive photocells! I think I flunked it also the electrode test was it right to say test between disconnected earth conductor to L1 L2 and L3 in turn and record highest as 3phase installation?

 

[nockster]

lol it was a 10 point question so Automatically assumed it was a 30mA as you only do a couple of tests for the other RCD's no 5X Tests

Same as, also did the equation but used the wrong resistance ( I think ) , this is what happens when you take a 8 year break from electrics and the boss dumps you in it !

 

[nockster]

I think u got the IR right, thats what i put, as for earth electrode, kinda sounds right !

 

[sornen]

What did you guys put for the three practical considerations before a periodic? ... And where the hell was the 1 over rt banker question!

 

[filrobbo]

fingers crossed...... I put the tripping time as 300 ms. wasn't sure.

 

[nockster]

Silly quote of the day, just before I leave for my exam my Mrs says "knock em dead babe", I tried to point out that this is exactly what the 2391 is trying to protect against lolololol.......

 

[IQ Electrical]

Silly quote of the day, just before I leave for my exam my Mrs says "knock em dead babe", I tried to point out that this is exactly what the 2391 is trying to protect against lolololol.......

She was reminding you of safe isolation...

 

[LlandrilloSpark]

Question asked you to IR test SWA section of lighting circuit only!, disconnect at the service cut out at base of column, so u didn't have to lower the test voltage because of photo cells