cg,ca,ci,cc

[telectrix]

Doh, sorry the tutor did mention Cg. Overlooked that.

Lets try again...

15A / Ca of 0.87

17.24A / Cg of 0.70

24.63A

Don't think Cc applies in this case as the cable is not buried in the ground (but I'm probably wrong).

Now check Table 4D2A.

it's 13A n ot 15, IMO gives 21.35A. so 2.5mm

 

[telectrix]

or, take 2.5mm ref, method C = 27A then multgiply by rating factors. 27 x 0.87 x 0.7 = 16.44, so 2.5mm will handle 13A.

 

[ackbarthestar]

Being wacked with a wet fish excluded, I would say that you maybe right and wrong

Method 4 = A
Method 3 = B

looking at app 4 table 4A2 number 3 = ref method B I think my internal translator got jammed

- I'll just take the money and run

 

[telectrix]

all this brain work is causing alcohol starvation, need beer to focus.

 

[JamesBrownLive]

it's 13A n ot 15, IMO gives 21.35A. so 2.5mm

I was taught that you apply rating factors to the CPD not to the load?? That's certainly how they teach it at www.LearningLounge.com.

Cheers

 

[lofty84]

ur telling me my exams in 2 hrs eeeek


the answer sheet i have gives the answer as 4mm2 so they have used the IN value (15a)


tele how did you no what to times things by on the industrial board question with the motors and that, just hoppe i dont get one of these types but i bet i do ....

 

[lofty84]

1 hr even

 

[ackbarthestar]

or, take 2.5mm ref, method C = 27A then multgiply by rating factors. 27 x 0.87 x 0.7 = 16.44, so 2.5mm will handle 13A.

Probably in real life this would not be appropriate, but I doubt for this example you would use the load to find your tabulated current since your final circuit has not been designed to incorporate overload protection.

Mr Pedant

 

[JamesBrownLive]

Being wacked with a wet fish excluded, I would say that you maybe right and wrong

Method 4 = A
Method 3 = B

looking at app 4 table 4A2 number 3 = ref method B I think my internal translator got jammed

- I'll just take the money and run

Are you looking at the BRB or BGB ??

BRB P.261
Method 3 = A
Method 4 = B

But I agree with Tel.... It's beero'clock.

 

[ackbarthestar]

Are you looking at the BRB or BGB ??

BRB P.261
Method 3 = A
Method 4 = B

But I agree with Tel.... It's beero'clock.

BRB
I was referring to ref methods translated from the 16th ed to 17th ed, not the row numbers in appendix 4 of the 17th ed.

 

[lofty84]

sorry guys but can anyone tell me where in the red book i can look to find out this question An industrial Board supples

- 4 TP motors
- 2 x TP&N motors
- 4 x single phase ring circuits
- 2 x single phase lighting circuits

how many live conductors are there

a)36
b)38
c)40
d)52

anyone know how to work that out ...

 

[JamesBrownLive]

BRB
I was referring to ref methods translated from the 16th ed to 17th ed, not the row numbers in appendix 4 of the 17th ed.

Well then we're both correct :beatnik: now where did I put that beer...

Cheers

 

[ackbarthestar]

sorry guys but can anyone tell me where in the red book i can look to find out this question An industrial Board supples

- 4 TP motors
- 2 x TP&N motors
- 4 x single phase ring circuits
- 2 x single phase lighting circuits

how many live conductors are there

a)36
b)38
c)40
d)52

anyone know how to work that out ...

The answer is knowing what a live conductor is, from part 2 definitions and knowing how many live conductors are required for each type of circuit.

The C&G 2382 level 3 assumes a certain level of installation knowledge before you start.

 

[lofty84]

i did my apprenticeship with a domestic sparky so have no idea unfortuneatly

 

[ackbarthestar]

Well then we're both correct :beatnik: now where did I put that beer...

Cheers

I'll send you a copy of my cert, you can change the name or use mine - up to you.