Help with 2391 question .......VOLT DROP.......

[ICE]

Hi Guys,

I have a past paper (March this year in fact) with a question I can not get my head round, am I mis reading it or am I just being thick, Here is the question exactly as it appears in the paper. If snyone can help me it would be much appreciated.

I know 3% 6.9V for lighting and 5% 11.5V for other circuits and that VD=Ib x (R1+Rn) x 1.2

If you can help can you please explain to me and also show all calcs, (model answer)
Cheers in Advance..



Determine, showing all calculations, the maximum permitted voltage drop on a low voltage (LV) installation supplied at 230V from the public supply network for a:

a) motor circuit
b)lighting circuit
c) socket outlet circuit

 

[old dog]

a) 230 x 5/100=11.5
b)230 x 3/100=6.9
c)230 x 5/100=11.5
the question is set to confuse like the rest of the 2391 questions

 

[ICE]

a) 230 x 5/100=11.5
b)230 x 3/100=6.9
c)230 x 5/100=11.5
the question is set to confuse like the rest of the 2391 questions

Thankyou,

You are a Gentleman and a Scholar


I would Kiss you but I am not that way inclined.


Cheers

 

[bomdiddly]

could u pls email me copy of paper got my 2391 soon revising of old papers thnx
[email protected]

 

[iceman]

hello chaps if ya dont mind me askin where does the 100 come frm in these calcs 230x5/ 100??? thnaks

 

[old dog]

hello chaps if ya dont mind me askin where does the 100 come frm in these calcs 230x5/ 100??? thnaks

hi iceman the 100 gives % the question is set to test that you know it is 3% lighting
and 5% everythingelse . they ask for all caculations to prove you are not just working
from memory.
so 230x your % value and devide by 100 gives you percetage
we all know its 6.9 lights 11.5 c&g want to know we can calculate and notr just work from
memory

 

[iceman]

thnks old dog thts cleared tht up ;-)