SLC21/WK6: Electricity bill and Electrical Cable, Circuit Breaker size Calculation
Hello steemians,
We are already in week 6 of the Steemit Engagement Challenge, and I am excited to share my participation on today's topic which is about calculating electricity bills as well as electrical wire and circuit breaker sizes. This was a great lesson, full of valuable information, and the tasks provided are equally interesting and engaging.
A. Write three key differences between XLPE and PVC cables.
XLPE (cross-linked polyethylene) and PVC (polyvinyl chloride) cables differ significantly in their properties and uses, which mainly result from the materials used for their insulation, their ability to withstand various environmental conditions and their behavior when faced with thermal or electrical constraints. These differences play a decisive role in choosing the type of cable to be used according to specific applications.
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The first major difference between these cables is their thermal performance, where XLPE cables, thanks to the chemical bonding process of the insulating materials can withstand higher temperatures up to 90 °C in continuous operation and up to 250 °C in continuous operation. In the event of a short circuit for a few seconds while PVC cables are limited to a temperature range of about 70 °C for continuous operation and 160 °C for short circuits, this difference makes XLPE cables particularly suitable for environments where high currents or extreme thermal conditions are common, such as in industrial or underground facilities.
The second major difference is resistance to environmental conditions including moisture and chemical agents, XLPE cables have very low water permeability and increased chemical resistance making them an ideal choice for installations in humid or aggressive environments, such as industrial or marine areas, on the other hand, XLPE PVC cables, although they provide good flexibility and basic resistance to humidity, are more likely to deteriorate under the action in the long term of water, which may shorten their lifespan when used in constant humidity environments or exposed to chemicals.
The third difference lies in the durability and aging of the material. XLPE cables, thanks to their cross-linked molecular structure, have better resistance to thermal aging, cracks due to mechanical fatigue and ultraviolet radiation. This gives them a much longer life, often exceeding 40 years, even in difficult conditions. In contrast, PVC cables, although very popular and economical, show faster deterioration, especially when exposed to fluctuating temperatures or sunlight, which limits their service life and reliability in long-term applications.
A. Write three key differences between single-core, two-core, and three-core cables.
Single-conductor, two-conductor, and three-conductor cables differ primarily in their structure, applications, and ability to handle electromagnetic fields, which determines their usage in specific electrical systems depending on power, safety, and performance requirements. disturbances.
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Difference 1: Physical composition and function of conductors
Single-core cables contain a single insulated wire, designed to carry a single phase or signal, and are often used in simple installations such as industrial power networks. Two-core cables ) have two wires, one dedicated to the phase and the other to the neutral, making them suitable for domestic appliances or single-phase circuits, and three-core cables include a wire for the phase, one for neutral and a third for earth, adding a level of safety thanks to earthing.
| Cable Type | Number of Conductors | Primary Use |
|---|---|---|
| Single-core | 1 | Single-phase or signal transmission in simple systems |
| Two-core | 2 | Single-phase circuits (phase and neutral), domestic appliances |
| Three-core | 3 | Three-phase systems or circuits requiring earthing for increased safety |
Difference 2: Scope of application
Single-conductor cables are favored in environments where high currents are required, such as transformers and distribution networks because they handle high currents efficiently, two-conductor cables are common in domestic applications, such as lamps or light appliances, while three-conductor cables are used in installations requiring increased safety, such as industries, where grounding is essential to protect against electric shock.
| Type of cable | Common applications | Typical environment |
|---|---|---|
| Single-core | High-power networks, industrial connections | Industrial installations |
| Two-core | Household appliances, lighting | Domestic use |
| Three-core | Industrial machines, three-phase systems with earthing | Environments requiring safety |
Difference 3: Management of electromagnetic fields
Single-conductor cables generate significant magnetic fields, especially when carrying high currents which can cause interference if not properly insulated or placed two-conductor and three-conductor cables reduce these fields thanks to their grouped arrangement, opposing currents partially cancel out interference, however three-conductor cables offer better interference management thanks to their balanced configuration and ground conductor, making them the ideal choice for complex or sensitive systems .
| Cable type | Interference management | Specific Advantage |
|---|---|---|
| Single-core | Generates a large magnetic field | Requires careful interference management |
| Two-core | Partially reduces interference | Partial cancellation of magnetic fields |
| Three-core | Offers better interference reduction | Enhanced stability with ground conductor |
A. Write about peak and off-peak hours in your country.
In Tunisia, peak and off-peak hours are influenced by the daily travel of workers and students, as well as seasonal patterns and variations in activity in major cities like Tunis, Sfax and Sousse, where main roads and public transport is experiencing significant traffic flows.
Peak hours are generally concentrated in the morning, between 7:00 a.m. and 9:00 a.m., when the majority of people go to work or school, and in the afternoon, between 5:00 p.m. and 7:00 p.m., when roads and public transport is saturated with those returning home after a day of activity, often creating traffic jams, especially near schools, industrial zones and main roads.
On the other hand, off-peak hours, which generally extend between 10:00 a.m and 4:00 p.m as well as after 8:00 p.m offer much smoother traffic and are often favored by traders and professionals who seek to optimize their travel and avoid the constraints of heavy traffic.
These variations in travel flows are also reflected in energy consumption, where peak energy times coincide with periods of high domestic activity, such as early in the morning before leaving for work and in the evening when using household appliances while off-peak times for electricity occur in the middle of the day and at night when activity decreases.
The times of year also play an important role, as during the summer peak hours can extend late into the evening, particularly in tourist areas and busy neighborhoods where locals and visitors alike enjoy the nighttime activity , while in winter, trips are more concentrated during the day due to the longer nights and lower temperatures, which modifies the usual rhythm of circulation and consumption.
This dynamic, although inevitable, can be anticipated to optimize journeys and reduce inconvenience linked to traffic jams or waiting on public transport, thus allowing better management of time and resources in the daily lives of Tunisians.
B. Calculate your house load and prepare the electricity bill for November 2024 by following Example 1.
In my house, eight 80-watt bulbs are on for 6 hours a day, and a 100-watt heater is on for 7 hours a day. The electric company's electricity bill per unit is 0.176 steam, my washing machine is 500 watts a day and my microwave is 1000 watts for 15 minutes a day. What will my electricity bill be in November 2024?
Light bulb consumption per day:
80 watts × 8 × 6 hours = 3840 WH = 3.84 KWH
Radiator consumption per day:
100 watts × 7 hours = 700 WH = 0.7 KWH
Washing machine consumption per day:
500 watts × 1 hour = 500 WH = 0.5 KWH
Microwave consumption per day:
1000 watts × 0.25 hours = 250 WH = 0.25 KWH
Total consumption per day:
3.84 + 0.7 + 0.5 + 0.25 = 5.29 KWH
Total consumption for November (30 days):
5.29 KWH × 30 = 158.7 KWH
Total bill:
158.7 KWH × 0.176 Steem = 27.93 Steem
The total electricity bill for November 2024 will be 27.93 Steem.
C. Calculate the total electricity bill with the HT meter values given in Example 2 and design an electricity bill in Excel.
Peak (R1) Calculation
R1 = (2665.26 - 2625.20) KWH = 40.06 KWH
R1 in units = 40.06 × 18000 = 721080 units
Off-Peak (R2) Calculation
R2 = (9825.21 - 9692.81) KWH = 132.4 KWH
R2 in units = 132.4 × 18000 = 2383200 units
Total KWH Verification
Total KWH = R1 + R2 = 40.06 + 132.4 = 172.46 KWH
Verification: Total KWH from meter reading = (12490.47 - 12318.01) KWH = 172.46 KWH
Total Electricity Bill
Peak Bill (R1):
Peak Rate = 1.5 Steem/unit
Peak Bill = R1 × 0.15 = 40.06 × 0.15 = 6.01 Steem
Off-Peak Bill (R2):
Off-Peak Rate = 1.0 Steem/unit
Off-Peak Bill = R2 × 0.10 = 132.4 × 0.10 = 13.24 Steem
Total Bill:
Total Electricity Bill = 6.01 Steem + 13.24 Steem = 19.25 Steem
Final Answer:
The total electricity bill for November 2024 is 19.25 Steem.
D. Figure out the cable and circuit breaker sizes you need to setup a 20 ampere, 220 volts, and power factor (PF) 0.9 washing machine at home.
The total power of the washing machine is calculated using the formula P=V×I×PF V is voltage (220 volts), I is current (20 amps), and PF is the power factor (0.9), by substituting these values the calculation becomes:
P=220x20x0.9=3960watts.
This is the total power required by the washing machine when operating in these conditions.
To determine the appropriate size of cable and circuit breaker, the total power is divided by three, a common practice to ensure safety and to account for potential current variations, this gives:
Adjusted power= 3/3960 =1320watts.
This adjusted power simplifies the process of selecting the right electrical components.
For an adjusted power of 1320 watts, 2.00 RM cable (equivalent to approximately 2mm² copper cable) is recommended, this size of cable can safely carry the current required by the machine washing while reducing risks such as overheating or voltage drops, if the distance between the washing machine and the electrical power source is large (e.g. greater than 15 meters), a larger cable size may be contemplated to compensate for tension losses.
Based on the adjusted wattage of 1320 watts and the current specifications of the washing machine, a C10 (10 amp) circuit breaker is fitted, this circuit breaker ensures that the electrical circuit is protected against overloads and short -circuits, thus avoiding damage to the washing machine and your home's electrical system.
Thank you very much for reading, it's time to invite my friends @cruzamilcar63, @mvchacin, @adeljose to participate in this contest.
Best Regards,
@kouba01
Greetings friend @kouba01
I see that electricity is a bit expensive in your country, although that may mean that the service is of quality, in my country, it is cheap but for several years its quality has been something to talk about. Regarding the calculations, this is the part that I like the most about electricity, I like to solve those formulations, what I don't like is the practice, I respect the current a lot.
Good post.