SLC21/WK6: Electricity bill and Electrical Cable, Circuit Breaker size Calculation.
Distinguished ladies and honorably gentlemen, my amiable fellow Steemians, you are all welcome to this week's presentation. Sit back and relax, and let's attend to the following questions.
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Ai. Write three key differences between XLPE and PVC cables. |
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Below are three key differences between XLPE (Cross-Linked Polyethylene) and PVC (Polyvinyl Chloride) cables:
1. Insulation Material and Properties
- XLPE Cables: XLPE cables make use of cross-linked polyethylene as the material for insulation. This material is known for top-notch electrical properties, high thermal stability, as well as resistance to abrasion and chemicals.
- PVC Cables: PVC cables make use of polyvinyl chloride as the material for insulation. While PVC is a good insulator, compared to XLPE, it is known to have lesser thermal stability and is more susceptible to degradation over time.
2. Temperature Rating and Fire Resistance
- XLPE Cables: These are higher temperature rated, which is up to 90°C, and therefore are more resistant to fire. They additionally generate less smoke and toxic gases anytime exposed to fire.
- PVC Cables: These are lower temperature rated, which is up to 70°C, and therefore are more susceptible to igniting and spreading fire. They additionally generate more smoke and toxic gases anytime exposed to fire.
3. Environmental Impact and Cost
- XLPE Cables: Cables are known to be more environmentally friendly, having a lesser carbon footprint. Nevertheless, they are commonly more costly than PVC cables.
- PVC Cables: Cables are less costly than XLPE cables but known for higher environmental impact as a result of the utilization of chlorine and other chemicals in their production.
ii. Write three key differences between single-core, two-core, and three-core cables. |
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The following are three key differences between single-core, two-core, and three-core cables:
1. Construction and Configuration
- Single-Core Cables: These are cables made up of a single insulated conductor coated with a protective sheath.
- Two-Core Cables: Two-core cables are made up of two insulated conductors jointly twisted and enclosed by a protective sheath.
- Three-Core Cables: These are cables composed of three insulated conductors jointly twisted and coated by a protective sheath.
2. Application and Usage
- Single-Core Cables: These cables are commonly utilized for earthing, bonding, as well as other applications in which single conductors are required.
- Two-Core Cables: Two-core cables serve typically for control circuits, lighting, as well as other applications that require two conductors.
- Three-Core Cables: Three-core cables are commonly employed for power distribution, motor control, as well as other applications requiring three conductors.
3. Flexibility and Space Requirements
- Single-Core Cables: Single-core cables are more flexible and require less space than two-core or three-core cables.
- Two-Core Cables: These cables are more lithy than three-core cables but less lithy than single-core cables.
- Three-Core Cables: They are the least flexible cables and need the most space as a result of the additional conductor.
iii. Write about peak and off-peak hours in your country. |
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Peak Hour:
The peak we know is the time when electricity is consumed the most in the day or at night. Therefore, we must look at it from two different angles. There is high usage of electricity at home from 5:00 AM to 7:00 AM when people prepare for work. From 8:00 AM to 5:00 PM, the usage is high at our various businesses or workplaces. 6:00 PM to 10:00 PM is another time of high usage. Hence, I can conclude from this illustration that the peak in my country is 5:00 to 10:00 PM.
Off-peak hours:
*This is the period when the use of electricity is less and this can only be when users have gone to rest as well as all appliances turned off except for security gadgets. Therefore, the off-peak in my county is usually from 10:PM to 4:00 AM.
B. Calculate your house load and prepare the electricity bill for November 2024 by following Example 1. |
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In my house, the following are the following are the the number of loads and their duration of usage:
• 12 pcs of 5W light, on for 9 hours per day
• 1 pcs of 120W Freezer, on for 24 hours (except when there is a power outage)
• 1 pcs of 90W TV, on for 3 hours per day
• 1 pcs of 440W washing machine, on for 2 hours per day
• 1 pcs of 1000W cooker, on for roughly 4 hours per day
• 1 pcs of pressing iron, on for an estimated 1 hour per day
• 1 pcs of ceiling fan, on for 10 hours per day
The electricity company's electricity bill per unit is ₦70.75 which is equivalent to 0.2 Steem
Now let's calculate the electricity consumption using the formula: Watts × Number of loads × Hours
Electricity consumption of light per day:
Watts × Number of loads × Hours = 5 × 12 × 9
= 540 WH
= 0.54 KWH (Since 1 KW = 1000 Watt)
Electricity consumption of freezer per day:
Watts × Number of loads × Hours = 120 × 1 × 24
= 2880 WH
= 2.88 KWH
Electricity consumption of TV per day:
Watts × Number of loads × Hours = 90 × 1 × 3
= 270 WH
= 0.27 KWH
Electricity consumption of washing machine per day:
Watts × Number of loads × Hours = 440 × 1 × 2
= 880 WH
= 0.88 KWH
Electricity consumption of cooker per day:
Watts × Number of loads × Hours = 1000 × 1 × 4
= 4000 WH
= 4 KWH
Electricity consumption of pressing iron per day:
Watts × Number of loads × Hours = 1200 × 1 × 1
= 1200 WH
= 1.2 KWH
Electricity consumption of ceiling fan per day:
Watts × Number of loads × Hours = 80 × 1 × 10
= 800 WH
= 0.8 KWH
Total consumption of electricity in a day:
= Light + Freezer + TV + Washing machine + Cooker + Pressing iron + ceiling fan
= (0.54 + 2.88 + 0.27 + 0.88 + 4 + 1.2 + 0.8) KWH
= 10.57 KWH
= 10.57 Unit
Total consumption of electricity for November 2024:
= Total electricity consumption in a day × 30 days
= 10.57 × 30
= 317.1 KWH
= 317.1 Units
Electricity Bill Per unit = 70.75 = 0.2 Steem
Total electricity bill for November 2024:
= Total consumption of electricity for November 2024 × Per Unit cost
= 317.1 × 70.75 = 317.1 × 0.2
= ₦22,434.83 = 63.42 Steem
C. Calculate the total electricity bill with the HT meter values given in Example 2 and design an electricity bill in Excel. |
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Calculating the total electricity bill with the HT meter values given in example 2
HT Meter Reading:
| 01-11-2024 | 2625.20 KWH | 9692.81 KWH | 12318.01 |
| 30-11-2024 | 2665.26 KWH | 9825.21 KWH | 12490.47 |
| Peak Rate | 1.5 Steem |
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| Off-Peak Rate | 1.0 Steem |
Formula:
R1(Peak) = (2665.26 - 2625.20)KWH × 18000 = ?
R1(Peak) = (40.06)KWH × 18000 = 721,080KWH
R2(Off Peak) = (9825.21-9692.81)KWH × 18000= ?
R2(Off Peak) = (132.4)KWH × 18000 = 2,383,200KWH
Total KWH = R1 + R2 = ?
Total KWH = 721,080 + 2,383,200
Total KWH = 3,104,280
Total KWH = (12490.47-12318.01)KWH = R1 + R2
Total KWH = (172.46)KWH = 721,080 + 2,383,200
Total KWH = 172.46KWH = 3,104,280
Total Electricity Bill = R1(Peak) × 0.15 = ? [Per Unit cost = 0.15 Steem(Peak)]
Total Electricity Bill = 721,080 × 0.15 = 108,162
Total Electricity Bill = R2(Off Peak) × 0.10 = ? [Per Unit cost = 0.10 Steem(Off-Peak)]
Total Electricity Bill = 2,383,200 × 0.10 = 238,320
1 KWH = 1 unit
D. Figure out the cable and circuit breaker sizes you need to set up a 20 ampere, 220 volts, and power factor (PF) 0.9 washing machine at home. |
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P = Power = ?
V = Voltage = 220 volts
I = Current = 20 Amp.
PF = Power factor = 0.9
We know,
Power (P) = V × I × PF
= 220 × 20 × 0.9
= 3,960 Watt
In determining the cable size and circuit breaker, the total power is divided by three.
P = 3,960/3
P = 1,320 Watt
Thanks so much for your time and patience in reading through this blog. I am inviting @bonaventure24, @rossnenye, and @luciouslucy
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In your assignment post you have highlighted three important differences between XLPE and PVC cables. It was nice that you highlighted each point very nicely. Temperature, insulation, and environmental effects are very well presented by you.You've got this point right. You have gained a clear understanding of the different core cable wires. You have indicated the peak hours and off peak hours of your country.(2)
You have calculated the electrical loads in your home and calculated the load watts. A calculation of how many hours the loads were running is mentioned. You have separately taken out units for lights, fans, fridges and other devices. Although it was clear it was time consuming for you. You could have done the calculation with the same formula which would have been much shorter and shorter. You have maintained the correct accuracy as yours. (1.8)
You have submitted your solution from HT meter reading. Calculated according to the readings and prepared a clear datasheet. Electricity bill excel sheet is very well presented. The consistency of the electricity bill and the analogy of creating Excel is a nice observation in your sheet. The solution from the reading lesson and is quite accurate. (2.8)
Here you have figured out the cable and circuit breaker sizes you need to set up a 20 ampere, 220 volt, and power factor (PF) 0.9 washing machine at home. But you made a little mistake in the last line calculation here. Here should have been 3960/3=1320. Maybe it's your typing mistake. I urge you to write correctly. (2.3)
Comment/Recommendation
**Scores| 8.9/10
Thanks for the review and the correction.