# ECE464 Power Electronics Engineering Assignments Solution

## Shops 1-5 max cable runs for final sub-circuits

 Fluorescent fittings 20 meters Exit lights 20 meters Light points 20 meters Exhaust fans 20 meters 10a socket outlets 24 meters 15a socket outlets 21 meters 20a 3 phase outlet 14 meters 25a 3 phase a/c 18 meters Instantaneous HWS 16 meters Storage HWS 19 meters

1. Max demand is required for each shop separately. Show all workings
2. Max demand is required for all shops combined
3. Consumer mains are to be buried enclosed in ground. Sub mains are to be run in roof space, enclosed on cable tray. You are to calculate size and volt drops of all circuits (ref AS/NZS 3000-AS/NZS 3008.1.1. Calculate all earth conductor sizes and check for and apply if applicable any de-rating factors
4. Main switchboard multiple master meter enclosure:

A. Design and detail using AZ/NZS 3000 and WA Electrical Requirements

B. Draw a single line diagram, protection devices, A/links (if any), N links, earth link, n-link, main earth, earth bonds and all conductor sizes.

### Solution

The circuit connection requires that the neutral connection and the conductors are continuous and connected by splicing and bonding conductor. Connect the ends using the soldering method or with connector and tapping. There are other research methods used in electrical circuit connection such as T joints with a metal enclosure. There are 5 shop units which are supplied with underground power and they have multiple masters metered. The circuit loading, the numbers of final sub-circuits and many other specifications have been left out deliberately. The table below analyzes the components of the electrical design of the shops.

1. Max demand is required for each shop separately. Show all workings
2. Max demand is required for all shops combined
3. Consumer mains are to be buried enclosed in ground. Sub mains are to be run in roof space, enclosed on cable tray. You are to calculate size and volt drops of all circuits (ref AS/NZS 3000-AS/NZS 3008.1.1. Calculate all earth conductor sizes and check for and apply if applicable any de-rating factors
4. Main switchboard multiple master meter enclosure:

A. Design and detail using AZ/NZS 3000 and WA Electrical Requirements

B. Draw a single line diagram, protection devices, A/links (if any), N links, earth link, n-link, main earth, earth bonds and all conductor sizes.

### Solution

The circuit connection requires that the neutral connection and the conductors are continuous and connected by splicing and bonding conductor. Connect the ends using the soldering method or with connector and tapping. There are other methods used in electrical circuit connection such as T joints with a metal enclosure. There are 5 shop units which are supplied with underground power and they have multiple masters metered. The circuit loading, the numbers of final sub-circuits and many other specifications have been left out deliberately. The table below analyzes the components of the electrical design of the shops

### Part 1: Sub-main Cables

 Individual Shop Max Demand #1 -#5 LOAD GROUP LOAD REMARKS BALANCE CALCULATIONS CONTRIBUTIONS PER PHASE R W B R W B B11 Double 10A socket outlets 8 8 8 7.8 7.8 7.8 B11 Single 10A socket outlets Single calculation on double socket 1 1 1 Place with double B11 Single 15A socket outlets, 1 phase Single calculation on double socket 3 3 3 Place with double B11 20 A 3 phase socket outlet [20A+75% REM AID 1 2 1 =50 50 50 50 C 25A 3 phase air conditioning unit AIC 75% ON 1-phase 1 18.2 C 15A 3 phase instantaneous HWS HWS 100% 4IGEST 1 1 1 R 100%, W 100%, B75% 15 15 11.2 A 20A storage HWS, 1 phase FLC 1 1 1 R 100%, W 100%, B75% 15 15 11.2 A Twin 36 w fluorescent fittings FLC 9 9*0.42A=3.78A 3.78 A 20 W exit lights FLC 2 2*100/230 =0.86A 0.86 A Tube 36W fluorescent fittings FLC 4 4*0.42 A = 1.68A 1.68 A Light points FLC 4 4 3.6 3.6 A Exhaust fans at 0.25a fan FLC 2 2 0.25*3.45*2 0.86 0.86 Max Demand 91.58 92.26 105.4

### Part 2&3: Mains Cable & Cable Selection

 CONSUMPTION FOR ALL SHOPS COMBINED MAXIMUM DEMAND TABLE ITEM TABLE COLUMN CABLE SIZE/CCC DE-RATING 96.413 A T3(4) 2 7 24 35mm2 / 122 A 50mm2/ 144 A N/A N/A Voltage Drop 4V Table/Column 41/6 50mm2 Vc =0.219 mV/mA Calculation Cable Size Co-ordination

### Part 4: Earth sizes- Fault current Performance

 Shop Fault Level Demand #1- #5 Sub-Mains Impedance (Zt) Current Fault Table: 30/30 Column: 3/2 Main Switch Type Voltage Amperage kA rating Hager HHA125U C 415 (3-phase) 125A 25kA Running Earth Size 25mm2 Clause 5 5 3 5 Structural Bond Size 25mm2 Clause 5 5 3 3 2 Switchboard Bond Size 25mm2 Clause 5 5 3 3 2 Water Bond Size 4mm2 Clause 5 8 3 2

### Part 5: Main switchboard, multiple master meter enclosure and unit sub-boards

In a nutshell, the AS3000/ANZ standards are adopted in Australia and New Zealand to regulate the building and electrical wiring for different types of buildings. The standards are given load codes which govern the length and diameter of cables used especially in earthing and underground cabling. The standards, specify, further the kind of insulation that is appropriate for the cables used to ensure losses are minimized.

#### References

1. AS3000/NZ1 (2007) Wiring Rules and Standards: Electrical Installations (known as the Australian/New Zealand Wiring Rules). Standards, Australia.