2391 dec 10 questions helppp

[kingstonelectri]

Can anyone help with these questions from dec 10 paper please....

11. state 3 methods of providing protection against electric shock for a 16a socket outlet circuit installed on a construction site.

18 state the
a)effect of the value of prospective fault current when it is measured within the installation at increasing distances from the origin.

19 state 3 factors that may affect the measured earth fault loop impedance value of a circuit, excluding final conductor circuit length and cross sectional area.

much appreciated

 

[j.mawer]

I would have thought, but am prepared to stand corrected as I don't have 2391

11) 704.410.3.10
i) reduced low voltage 411.8
ii)ADS (411) with additional protection of an RCD as specified in 415.1.1
iv) selv/pelv

18) Increasing distance from origin would cause pfc to decrease, as the earth loop impedance will increase (R1+R2 increases)

19) i) Earthing arrangement TT TNC-S TNS
ii) Distance from transformer (further away increases Ze)
iii) weather conditions (wet weather decreases Ze)

 

[Deleted member 26818]

19) I would go with, parallel paths, poor terminations and conductor temperature.

 

[SMB]

Okay, im pushing myself on a limb here cause im a bit fick innit.....but heres my thoughts..

ANS 11.....use an RCD. Use 110 volts. (struggling with the third one.....errr...use a generator?)

ANS 18.....the pfc will become lower the further away from the supply origin?

ANS 19....depending if a TN-C-S, TNS or TT system?


Please don't trust me im a village idiot, but the above might be food for thought.

All the best.

 

[j.mawer]

oo I like the parallel paths and conductor temperature much more satisfying