Hi,
I am currently working on the project part for my C&G 2396 design qualification. I have passed the exam but that was 2 years ago and I have forgotten so much
.
I cannot for the life of me get my head around calculating and designing the sub main cable to a 3 phase DB with a mix of 3 phase and single phase circuits.
I know it’s probably simple (I hope) but just need a bit of audience if possible.
So…. If I have a 3 phase DB which contains
6x single phase circuits
1x 16A 3 phase circuit. (Lift)
Do I need to convert all circuits to Watts then add them together and do calculation
Watts / √3x400xpf
That will give me the Ib per line (phase)
Then use this figure to calculate the sub-main supply cable for the DB in question.
Is there another way??
Obviously I will add diversity to each circuit and use those figures in the above calculations……but do I have the correct understanding of the method needed??
Regards,
I am currently working on the project part for my C&G 2396 design qualification. I have passed the exam but that was 2 years ago and I have forgotten so much
.I cannot for the life of me get my head around calculating and designing the sub main cable to a 3 phase DB with a mix of 3 phase and single phase circuits.
I know it’s probably simple (I hope) but just need a bit of audience if possible.
So…. If I have a 3 phase DB which contains
6x single phase circuits
- 4x 20A socket circuits
- 3x lighting circuits (800w,640w,200w)
1x 16A 3 phase circuit. (Lift)
Do I need to convert all circuits to Watts then add them together and do calculation
Watts / √3x400xpf
That will give me the Ib per line (phase)
Then use this figure to calculate the sub-main supply cable for the DB in question.
Is there another way??
Obviously I will add diversity to each circuit and use those figures in the above calculations……but do I have the correct understanding of the method needed??
Regards,
