2365 305 Project

[rideontime]

Hi guys,

I'm working on my project, doing okay but run into the occasional roadblock and have decided to use this thread to hopefully get assistance.

Will post problems as they arise.

 

[rideontime]

Reserved

 

[rideontime]

Been working on applying diversity and balancing the phases for a 3-Phase electrical installation in a commercial hotel for a cafe/pool block.

I started by listing the circuits and decided what diversity I could apply using OSG as a reference but also using my own judgement. The distribution circuits are broken down in other tables, and I've accumulated the Ib figures from the submain circuits to work out my Ib for the distribution circuits - I don't know if this is an acceptable method?

NB regarding the design currents, for alot of the equipment no information regarding power draw is given so ended up using a design current that equals the rating of the protective device.

Circuit Name	Design Current	Diversity applicable
Swimming pool 3P distribution circuit	48A, 33.6A, 32.74A respectively	See table below
Summerhouse distribution circuit	19.04A	See table below
Kitchen radial	32A	OSG Table A2 Row 10
Dining room radial	16A	OSG Table A2 Row 10
Fridges supply - 1	16A	None - will be on constantly
Fridges supply - 2	16A	None - will be on constantly
Dishwasher	16A	OSG Table A2 Row 2
Food holding equipment 3-phase supply	16A each phase	OSG Table A2 Row 2
Vending machines supply	10.43A	None - will be on constantly
Fire alarm	13A	None - will be on constantly
Lighting - Kitchen	0.89A	None - I expect all the lights to be on.
Lighting - Dining Area 1	2.09A	None - I expect all the lights to be on.
Lighting - Dining Area 2	0.36A	None - I expect all the lights to be on.

Swimming pool submain (located in equipment room)

Circuit Name	Design Current	Diversity Applicable
Pool and pump equipment 3-phase supply	32A each phase	OSG Table A2 Row 2
Changing rooms radial	16A	OSG Table A2 Row 10
Lighting - Pool	1.6A	None - I expect all the lights to be on.
Lighting - Wall lights and changing rooms	0.74A	None - I expect all the lights to be on.

Summerhouse submain

Circuit Name	Design Current	Diversity Applicable
Summerhouse radial	16A	OSG Table A2 Row 10
Summerhouse lighting	3.04A	None - I expect all the lights to be on.

There are some circuits which I was unsure whether applying diversity would be acceptable. The vending machines, fridges, fire alarm, etc - hopefully someone can advise.

Anyhow, I then went deciding which circuits should go on which phase but didn't end up applying too much in regards to diversity; the 4 radial circuits are split between the phases so only one phase had two of them, which means I could only take 40% current demand from one of them for my max demand figure. The only other area I managed to apply diversity was to the dishwasher where I took 80% of demand based on osg.

After moving circuits between phases I managed to get the following loads: 84.58A, 99.87A, 93A. These loads could probably be better balanced, but I was trying to get it so I could use a 100A fuse. Probably a mistake on my part, would seem better to balance as best as possible and the fuse size is what it is.

 

[rideontime]

Had a quick chat with my teacher and realized I had applied diversity wrong. I was following this example where diversity was applied per phase, but it seems for the project we should be applying diversity to the installation as a whole.

I also learned that design current is after the application of diversity.

I decided to apply diversity to more circuits that I originally decided shouldn't have diversity apply. Did some research on the fridges to realize they run on a cycle and have decided Table A2 OSG reference 10 applies. With the vending machines, I believe they use most power when being used (duh) so have also applied Table A2 OSG reference 10. Dishwasher switched from using reference 2 to reference 10.

I'm still clueless as to how to apply diversity to the following circuits:

• Pool equipment and sauna equipment 3-phase supply (32A per phase)
• Servery food holding equipment 3-phase supply (16A per phase)

On the surface, I believe Table A2 OSG Reference 2 can apply to both these circuits, but due to them being 3-phase, I'm not sure how I would correctly apply diversity and have 2 ways in my mind.

Reference 2: 100% f.l. of largest appliance + 80% f.l. of largest appliance + 60% f.l. of remaining appliances.

Way 1: Apply 100% f.l. to all 3 phases of pool and sauna equipment supply, and 80% f.l. to all 3 phases of servery food holding equipment supply.

Way 2: Apply 100% f.l. of largest appliance to 1 phase of pool and sauna equipment, 80% f.l. to next phase, 60% f.l. to last phase then apply 60% f.l. to all 3 phases of the servery food holding equipment.