PFC

[carshalton]

A prospective fault current test is to be carried out on a new single phase installation consisting of a number of distribution boards ,

A, The two measurements that are required to determine the PFC ?

B, Were on the installation the tests in [A] May be appilied other than the orgin?

A,,Is the answer to A , PFC and PSCC,

B,, At the relelavant points ,

Are these right ??its the best i can come up with ??

i got these questions on a mock paper

Many Thanks Alan ..

 

[sparkytim]

A yup

B At all distribution boards

 

[NozSpark]

PFC is the higher of PEFC & PSCC and is measured at all relevant points of the installation(well that's what the regs says)

 

[wozz]

sounds like a 2391 question, not sure if you will get a mark for putting 'all relevant points' might be a bit too vague.

 

[NozSpark]

If it is a 2391 question and that is what the regs says then you will get the marks,,, however if they ask you what the relevant points are then you'll need to have an answer for that also

 

[carshalton]

Yes it is a 2391 question , no they don`t ask for which relevant points if they did , Were would these be ? i no at the orgin you can get it by enquiry or measurement but at other points you can only get it measurement

Many Thanks Again Alan ,

 

[wozz]

i would say something like 'at any point where protective device Icn decreases' could be wrong though as i havnt sat the exam yet.

 

[Nicky Tesla]

A, The two measurements that are required to determine the PFC ?

A,,Is the answer to A , PFC........ and PSCC,

youve answered the question with the question ie the PFC measurement is required to determine the PFC? Seems a bit odd way of asking.

Also measuring the Ze and the mains voltage can determine the PFC by doing the calc.

 

[spinlondon]

PFC is determined by dividing the voltage by the earth fault loop impedance.

PSCC is determined by dividing the voltage by the impedance of line plus neutral.

 

[NozSpark]

PFC is determined by dividing the voltage by the earth fault loop impedance.PSCC is determined by dividing the voltage by the impedance of line plus neutral.

Sorry, that's not right..

PEFC is the Prospective Earth Fault Current

PSSC is the Prospective Short Circuit Current

PFC (Prospective Fault Current) is the higher of PEFC and PSCC

all measurements for the above are taken with all earths and bonds connected

 

[wozz]

If it is a 2391 question and that is what the regs says then you will get the marks,,, however if they ask you what the relevant points are then you'll need to have an answer for that also

get what question came up thursday night, 'what are these relevant points?'