2391

[sparky71]

Sat my 2391 in aug got the results back over the phone failed
Did not say what area I failed on
Is there any way to revise and remember all gn3

 

[p11jor]

Hi sparky71 sorry to hear this.......I can help you if you want to pm me some stuff you think you may of struggled on and maybe give you some guidance on stuff that will Probably pop up......I didn't even look at GN3 and I passed it and know I would pass it every single time.

First of all can you remember whereabouts you struggled?

 

[sparky71]

Thanks I think I might of struggled on part be
Of paper
I know what to do but put it down on paper and
Explain no good lol

 

[sparky71]

Think I failed on part b of paper

 

[p11jor]

Right ok well on mine I had a earth fault loop diagram.......that you can get say 11-12 points just for drawing it

Then I had a IR test

Bullet point the whole procedure.

Warning signs
Warn people of test carrying out
Isolate and lock
Sensitive equipment removed & linked out

Etc etc

Then at the end check results against bs7671 to make sure comply then reinstate circuit to original condition ......there's 2 extra points at the end

Then I had a test sheet there was like 7 zs results that were below the maxium stated but not within 80% of so they were flagged, then there will always be a IR of like 0.23 n-e with say 299 either side of it, just watch out for them.

The earth electrode test popped up on mine that's a GN3 thing as hard to explains on here you would need the illustrations.......15 marks again rekon I proble got about 7 on that as I don't know that fully which I regretted when I left the exam!

 

[sparky71]

Thanks I had trouble how to explain ring circuit
Test and the procedure

 

[p11jor]

I would say Somthing like this......

Put up warning signs and warn people I testing

Dead test so safe isolation and lock off

Check machine complies with gs38 ....2-4mm tip, finger guards, inline fuses, 1000v insulated leads, no defects on machine, calibration certificate.

Then set machine on the low ohms scale

Null your test leads out or take reading of leads and subtract from result. (would just stick with null)

Prepare conductor for test.

Take end to end reading of line, & nuetral they should be withing 0.05 Then the cpc reading should be 1.67 times greater.

Then cross over the outgoing Nuetral to the incoming line and vice versa. And take the results at each point o the circuit to ensure no loops etc again they shoul be withing 0.05

Then do the same with your line & earth and test at each point the highest reading should be the one recorded, if a result is particularly higher then this will be a spare wired that result shoul be recorded.

Reinstate circuit to original condition and proceed to next test.


Should get close to maxium marks for that

 

[sparky71]

Thanks again

 

[sparky71]

What's the difference between the Icn and Ics
Ratings of a bs en 60898

 

[sparky71]

What is the list of the correct sequence five tests that are required to be conducted on newly installed lighting circuit

 

[Billythekid]

What's the difference between the Icn and Ics
Ratings of a bs en 60898

IIRC

Ics is the fault current that can pass through the device three times without affecting performance.

Icn is the fault current that can pass through the device twice without affecting performance.

hth

Billy

 

[p11jor]

Continuity of cpc
IR
Polarity
Zs
Rcd

 

[p11jor]

If you mean zs of them from the top of my head I think

6a - 7.67
10a - 4.6
20a - 2.3
32a - 1.44
40a - 1.15

 

[p11jor]

I was always taught CRIPPLER

Continuity of cpc

Ring final continuity

Insulation resistance

Polarity dead

Polarity live

Loop (Ze)

Elz (zs)

Rcd

 

[sparky71]

Thanks again you have been very helpful