Few small questions stuck on

[m4tty]

Hi,

Few questions im stuck on for coursework if anybody can help please

1) Which of the following is not a means of basic protection

a) FELV

B) SELV

c) PELV

d) Double/Reinforced Insulation

2) Cont CPC test method 1. Which of the following is the correct sequence of Mathematical operations to determine resistance of CPC (R2)?

a) R1+R2 : R1+RN : (R1+RN)/2 : R2=R1+R2 / (R1+RN)/2

B) R1+R2 : R1+RN : (R1+RN)/2 : R2=R1+R2 + (R1+RN)/2

c) R1+R2 : R1+RN : (R1+RN)/2 : R2=R1+R2 - (R1+RN)/2

d) R1+R2 : R1+RN : (R1+RN)/2 : R2=R1+R2 x (R1+RN)/2

Just trying to get some coursework done and cant get my head round these at the moment.

Thanks in advance

Matt

 

[Danny]

Well all the options in Q1 fall into the category of fault protection so at a glance the answer is none ...

Basic prot is barriers and enclosures and insulation of live parts, Fault prot includes ELV, separation and double/reinforced insulation which is all of those...

Is there an option for none?

However i have been to the pub ....

 

[Andy™]

Hi,Few questions im stuck on for coursework if anybody can help please

1) Which of the following is not a means of basic protection

a) FELV

B) SELV

c) PELV

d) Double/Reinforced Insulation

2) Cont CPC test method 1. Which of the following is the correct sequence of Mathematical operations to determine resistance of CPC (R2)?

a) R1+R2 : R1+RN : (R1+RN)/2 : R2=R1+R2 / (R1+RN)/2

B) R1+R2 : R1+RN : (R1+RN)/2 : R2=R1+R2 + (R1+RN)/2

c) R1+R2 : R1+RN : (R1+RN)/2 : R2=R1+R2 - (R1+RN)/2

d) R1+R2 : R1+RN : (R1+RN)/2 : R2=R1+R2 x (R1+RN)/2

Just trying to get some coursework done and cant get my head round these at the moment.

Thanks in advance

Matt

1 is A

mind has gone blank to question 2!

 

[Marc]

2 is C, no?

 

[PC Electrics]

2 is C, no?

Yes

 

[SPECIAL LOCATION]

Hi,Few questions im stuck on for coursework if anybody can help please

1) Which of the following is not a means of basic protection

a) FELV

B) SELV

c) PELV

d) Double/Reinforced Insulation

2) Cont CPC test method 1. Which of the following is the correct sequence of Mathematical operations to determine resistance of CPC (R2)?

a) R1+R2 : R1+RN : (R1+RN)/2 : R2=R1+R2 / (R1+RN)/2

B) R1+R2 : R1+RN : (R1+RN)/2 : R2=R1+R2 + (R1+RN)/2

c) R1+R2 : R1+RN : (R1+RN)/2 : R2=R1+R2 - (R1+RN)/2

d) R1+R2 : R1+RN : (R1+RN)/2 : R2=R1+R2 x (R1+RN)/2

Just trying to get some coursework done and cant get my head round these at the moment.

Thanks in advance

Matt

Q1 as Andy said FELV...

you will be wanting to read 411.7 on Functional extra low Voltage FELV

page 52 Big red!

reg 411.7.1 refers to occassions where FELV does not meet all of the requierments of SELV & PELV then supplimentray provision for basic protection must be included as per 411.7.2.

Q2

a) R1+R2 : R1+RN : (R1+RN)/2 : R2=R1+R2 / (R1+RN)/2

B) R1+R2 : R1+RN : (R1+RN)/2 : R2=R1+R2 + (R1+RN)/2

c) R1+R2 : R1+RN : (R1+RN)/2 : R2=R1+R2 - (R1+RN)/2

d) R1+R2 : R1+RN : (R1+RN)/2 : R2=R1+R2 x (R1+RN)/2

as has been said the anser is 'C'

for the benifit of others I will just explain whyn it is 'C'.

assuming you have readings for

R1+R2

and

R1+RN

in T&E R1 csa = RN csa, so R1 csa = (R1+RN/2).

so you now have R1.

now R2 = your (R1+R2)-R1

or

R1+R2 - (R1+R2)/2

 

[m4tty]

Thanks everyone well appreciated

 

[monkey5]

i think i follow q2 but ot 100% whats the ":" mean?

sorry to be dim

wayne

 

[Marc]

i think i follow q2 but ot 100% whats the ":" mean?sorry to be dim

wayne

I think it's something along the lines of "and then"; measure R1+R2, and then R1+Rn, etc.