Diversity....... Not the PC kind......

[revjames]

Hi guys, another problem with working out diversity. Table 1B in the OSG page 97 in the middle column states 90% of current demand for lighting. Do I take that as IB - the design current ie what the actual circuits will be using or IN the rating of the protective device?

Also with regard to the ring final circuits the guide states that 100% of the first then 50% of remaining circuits. Now does that mean per DB (there are 5 sub main boards) or the whole installation?

I would appreciate your replies guys as I really want to nail this today if I can.

 

[Marc]

Hi guys, another problem with working out diversity. Table 1B in the OSG page 97 in the middle column states 90% of current demand for lighting. Do I take that as IB - the design current ie what the actual circuits will be using or IN the rating of the protective device?Also with regard to the ring final circuits the guide states that 100% of the first then 50% of remaining circuits. Now does that mean per DB (there are 5 sub main boards) or the whole installation?

I would appreciate your replies guys as I really want to nail this today if I can.

Deisng current.

Ring finals - per DB. I prsume you're calculating cable sizes for each individual DB? Diversity applies to each individual sub-main, not as a whole installation.

 

[revjames]

yep thats right so its 90% of the design current of each lighting circuit then 50% of the second final circuit from each DB. I think I have it now. Thanks

 

[NozSpark]

Diversity is an ass!!!

But here's what I have

http://www.flickr.com/photos/n-e-electrical/4356155195/sizes/l/

 

[revjames]

Diversity is an ass!!!But here's what I have

http://www.flickr.com/photos/n-e-electrical/4356155195/sizes/l/

Thats pretty much what I read in the OSG this is what I finally came up with (sorry its long)

Maximum demand for the whole installation

Using Table 1B in Appendix 1 On Site Guide

DB1 Circuit No. Ib After diversity

L1 L2 L3

Ring Final Circuit DB1 L1 1 32A 32A

Ring Final Circuit DB1 L2 1 32A 16A

Lighting Circuit DB1 L3 1 4.3A 3.9A

Lighting Circuit DB1 L3 2 4.3A 3.9A

Lighting Circuit DB1 L3 3 4.9A 4.4A

Lighting Circuit DB1 L3 4 2.2A 2.0A

Lighting Circuit DB1 L3 5 5.1A 4.6A

DB2 Circuit No. Ib After diversity

L1 L2 L3

Ring Final Circuit DB2 L1 1 32A 32A

Ring Final Circuit DB2 L3 1 32A 16A

Lighting Circuit DB2 L2 1 5.8A 5.2A

Lighting Circuit DB2 L2 2 3.7A 3.3A

Lighting Circuit DB2 L2 3 3.7A 3.3A

Lighting Circuit DB2 L2 4 3.7A 3.3A

Lighting Circuit DB2 L1 2 2.2A 2.0A

Lighting Circuit DB2 L3 2 5.2A 4.7A

DB3 Circuit No. Ib After diversity

L1 L2 L3

Ring Final Circuit DB3 L2 1 32A 32A

Radial Circuit DB3 L1 1 20A 10A

Lighting Circuit DB3 L3 1 3.4A 3.1A

Hand Drier DB3 L1 2 3.9A 3.9A

Lighting Circuit DB3 L3 2 4.3A 3.9A

Lighting Circuit DB3 L3 3 4.9A 4.4A

Lighting Circuit DB3 L3 4 4.9A 4.4A

Lighting Circuit DB3 L3 5 2.9A 2.6A

DB4 Circuit No. Ib After diversity

L1 L2 L3

Ring Final Circuit DB4 L2 1 32A 32A

Ring Final Circuit DB4 L1 1 32A 16A

Fridges DB4 L3 1 10.4A 10.4A

Cooker DB4 L2 2 18.3 18.3A

Coffee machine DB4 L2 3 11.7A 11.7A

Dishwasher DB4 L3 2 18.3 18.3A

Lighting Circuit DB4 L1 3 2.9A 2.6A

Lighting Circuit DB4 L2 4 3.5A 3.2A

Lighting Circuit DB4 L3 3 2.9A 2.6A

Lighting Circuit DB4 L3 4 2.9A 2.6A

Lighting Circuit DB4 L3 5 2.2A 2.0A

DB5 Circuit No. Ib After diversity

L1 L2 L3

Ring Final Circuit DB5 L1 1 32A 32A

Hand driers DB5 L2 1 7.8A 7.8A

Hand Driers DB5 L3 1 7.8A 7.8A

Lighting Circuit DB5 L2 2 1.8A 1.6A

Lighting Circuit DB5 L2 3 1.8A 1.6A

Lighting Circuit DB5 L3 2 4.9A 4.4A

Lighting Circuit DB5 L3 3 4.9A 4.4A

Lighting Circuit DB5 L3 4 4.9A 4.4A

Lighting Circuit DB5 L2 4 4.4A 4.0A

HVAC HVAC 63A 63A 63A 63A

LIFT LIFT 63A 63A 63A 63A

Total Maximum demand on installation 256.5A 237.3A 240.8A

What do you think?

 

[revjames]

Stupid forum software messed up my cut and paste!