Please help!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[mick78]

please help i have been given a piece of coursework to complete. it involves doing an electrical install on a 6 bed country house with 2 floors with a total floor space of 170 sq m on each floor.

i am completely new to this whole concept.
from what i have read so far i have to do this in stages like finding design current Ib etc.

do i have to use 2 ring mains for downstairs sockets because of floor space? as well as separate ring for kitchen.

do i have to do the same for lights?

i was trying to work out design current by adding up all loads eg, 2000W for hoover, 300W for television etc is this correct?

but have also found that ring circuits have to be 32A is this correct.?

do i apply diversity to the 32A or the summation of all loads?

lecturer has let slip that house is supplied single phase. if i have all these circuits can i get this single phase? ( is there a limit )

any help greatly appreciated.

 

[PC Electrics]

So are you saying that the only variable to consider when choosing circuit type is the floor area? is this what has been taught at college?

Go back to first principles. Generate a list of variables to consider when making such a design choice.

I'll start you off:
# building construction and how it affects circuit length (eg concrete ground floor will lead to lots of drops to sockets from ceiling void which in turn leads to a very long circuit if you only put in one)
# position of cu and how that affects circuit lengths
# insulation between floors and how this affects installation methods.
# sizes and types of rooms and how this affects loadings

and that's just four items ottomh.

I'm not getting at you, but you seem ill prepared for the task. That's the fault of your education establishment.

 

[goldie]

So are you saying that the only variable to consider when choosing circuit type is the floor area? is this what has been taught at college?

Go back to first principles. Generate a list of variables to consider when making such a design choice.

I'll start you off:
# building construction and how it affects circuit length (eg concrete ground floor will lead to lots of drops to sockets from ceiling void which in turn leads to a very long circuit if you only put in one)
# position of cu and how that affects circuit lengths
# insulation between floors and how this affects installation methods.
# sizes and types of rooms and how this affects loadings

and that's just four items ottomh.

I'm not getting at you, but you seem ill prepared for the task. That's the fault of your education establishment.

...............and the dreaded correction factors for cable size to add to the list. TBH pc electrics, floor area became a subject because we were misled about it as we were stating the unlimited sockets within 100sq metres rule.

 

[PC Electrics]

unlimited sockets in 100 sqm rule.

Again, not the only rule to be considered. Take the first scenario I mention, if you were to put an rfc over 100sm in this instance you could well end up with a ring well in excess of the 117m max recommended for voltage drop and maybe even exceed disconnection time requirements.

 

[mick78]

pc electrics you sound as if you know what you are talking about. how about i slip you a fiver and you can sort this out!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[overskilled]

My main trade is IT, and sadly what I have noticed is the standard of teaching has dive bombed due to the internet, and some students have divebombed in standards (this isn't a dig mick, more a general observation) as its too easy to go online and ask someone to explain it, rather than previously where reading the books would be required and teachers were required to be able to teach the subject and clarify any unclear areas in the test. Also now there seems to be too many chances given, whereas before after 2 or 3 fails a quiet word might have been given regarding suitability for the subject / trade.
Though there are times you get too much info on courses and have to filter out the useless stuff and other times there isn't enough info given leaving you with umpteen different ways of doing it and likely only 1 approved way.
From my experience, someone who can justify and explain the choices they have made (even if slightly off the mark) tends to be marked more favourably than someone who has pretty much got it all there but can't / hasn't explained their choices, as understandably it demonstrates a lacking of understanding of the principles.
What stage are you at mick?