2391-20 anyone else doing it

[Lurch]

I have found some info online but fairly basic stuff. I need to know what impact it might have for example on the sub main to the DB. electricity will be flowing in 2 directions, I would have thought it would lighten the load if anything??

It could, but can;t be guaranteed to so worst case scenarios will have to be allowed for.

 

[revjames]

Hmmmm I am now thinking the best way might be (as there are 3 solar arrays) bring the 3 DC supplies down to the main switchroom, 3 DC isolators, 3 inverters 3 AC isolators and feed back into main CCU and metering. Do you think the DC isolators would need to be local ie near the solar arrays or OK in the switchroom downstairs?

 

[revjames]

Made some good progress today. Cant help thinking theres something wrong though. Question 4: "Determine for all circuits, including distribution circuits, the

a) Design current Ib

B) Nominal rating of protective device In

c) minimum size of live conductoirs for current carrying capacity and voltage drop"

questions 1-3 took roughly a page or 2. This question has taken over 20 pages to complete. Admittedly I typed it all on the computer so its neatly laid out and spaced things out well but 20 pages!

 

[ADS]

As for the title of this thread the answer is obviously NO! I was hoping that there would be others doing the same course on here. Hopefully you guys may find it interesting and as always I very much appreciate and value your input.

Hi Rev,

It is interesting so please don't stop posting! - even if it does feel like you're talking to yourself

I want to take this course sometime so I'm enjoying reading what you're having to do and how you are getting round your problems.

Cheers

 

[revjames]

Thanks ADS, its been an interesting course. A prerequisite is the 2391-10 and it follows on well from that course. I am just trying to wrap up this project now after months of procrastination. Theres another question that I would like some thoughts on:

"determine for the lighting circuits in function room 1, the total earth loop impedance Zs"

total Zs? I'm confused. Now there is a sub main feeding this area so there would be

Ze + Zdb + (R1+R2) do I do R1+R2 for just the furthest point on the lighting? there are 4 actual lighting circuits in the room concerned, do I add them all up?

I have a feeling when they say 'total' they want to make sure I include the impedance of the sub DB feed Zdb....

What do you think am I missing something?