what size wire to use ona 4tonair conditioner
Autonomously from the electrical current, wire sizes are also depending on other conditions such as ambient temperature and voltage drop. If you lot are dealing with air conditioners, it is inevitable that you'll see wire sizing work. So, I've made a wire size chart equally well equally a guide on how to summate wire size.
To calculate wire size for air conditioners, separate the maximum electric current by eighty% to observe the circuit breaker size. Adjacent, use the wire length and a voltage driblet of 2.5% to go the allowable voltage drop. Finally, choose the suitable wire size based on the circuit breaker ampere and the allowable voltage drop.
Sizing wire has been a difficult chore for many people fifty-fifty engineers. For near people, using the following wire size chart should be sufficient. For engineers, I'll go through step by step on how to calculate wire size.
Blueprint and sizing skills are essential to HVAC engineers. Nevertheless, manual calculations are inefficient. Hence, I arranged nine excel calculators, 5 diagrams and 3 charts in my Design Engineer Starter Pack which I encourage you to bank check it out as it can take your blueprint skills to the next level.
Wire Size Chart past Air Conditioner Chapters
- Ambience temperature = 86°F (xxx°C)
- Wire length = 50 ft (15 1000)
- Wire material = Copper
- Voltage drib = 2.5%
| Wire Size | AC Capacity | Max. Current |
|---|---|---|
| two.5mm2 (14 awg) | 0.75 Ton | 5.0 amps |
| 2.5mm2 (14 awg) | 1 Ton | 6.5 amps |
| 2.5mm2 (fourteen awg) | one.5 Tons | x.0 amps |
| two.5mm2 (14 awg) | ii Tons | 15.v amps |
| 4.0mm2 (12 awg) | 2.5 Tons | 17.0 amps |
| half dozen.0mm2 (10 awg) | 3 Tons | 25.5 amps |
| Wire Size | AC Capacity | Max. Electric current |
|---|---|---|
| ii.5mm2 (fourteen awg) | 3 Tons | 9.0 amps |
| ii.5mm2 (14 awg) | iii.5 Tons | 10.5 amps |
| ii.5mm2 (14 awg) | iv Tons | 12.0 amps |
| 2.5mm2 (14 awg) | iv.v Tons | xiii.5 amps |
| 2.5mm2 (14 awg) | five Tons | fifteen.0 amps |
Wire Size Chart by Amperage
- Ambient temperature = 86°F (30°C)
- Wire length = l ft (15 m)
- Wire material = Copper
- Voltage drib = 2.five%
| Wire Size | Wire Size | Amperage |
|---|---|---|
| 4 mm2 | 12 awg | 20 amps |
| 6 mm2 | ten awg | 30 amps |
| 10 mm2 | eight awg | xl amps |
| 16 mm2 | six awg | 50 amps |
| 25 mm2 | 4 awg | 60 amps |
| Wire Size | Wire Size | Amperage |
|---|---|---|
| 4 mm2 | 12 awg | xx amps |
| 10 mm2 | 8 awg | 30 amps |
| 10 mm2 | eight awg | twoscore amps |
| 25 mm2 | half dozen awg | l amps |
| 25 mm2 | half dozen awg | sixty amps |
How to Summate Wire Size for Air Conditioner?
Calculating the wire size for air conditioners is slightly different from other applications because the running ampere of air conditioners vary based on operating conditions. With that said, here is how y'all calculate wire size for air conditioners.
1. Identify the Load (Ampere)
The first step to calculating wire size is to place the load in terms of electric current. For appliances such every bit fan motors and pumps, the current flowing through the wire is more or less the same. Simply, it is significantly unlike for air conditioners.
The amount of ampere fatigued by air conditioners is mainly afflicted by the cooling need and the outside air temperature. The greater the cooling need, the higher the ampere. The college the outside temperature, the higher the ampere.
Many engineers employ rated power or rated electric current to calculate wire size for air conditioners which is inappropriate because the ampere of the air conditioners can be doubled when running at full load, especially during hot days.
For instance, a 415V three phase air conditioner with 67kW of capacity may have a rated power and a rated current of 19kW and 31A respectively. However, its maximum electric current is stated at 55A. So, if you use 31A to size its wire, information technology may non be enough.
Hence, the proper way to calculate wire size for air conditioners is to find out the maximum current of the air conditioner and utilise it to calculate the wire size needed.
2. Make up one's mind the Circuit Breaker Size
Next, yous need to determine the circuit breaker size. To detect the proper circuit breaker size for air conditioners, take the maximum current of the air conditioners and carve up it by 80%. Then, the next closest circuit billow size will be the one you lot are looking for.
Permit'south continue the above example and say I have an air conditioner with a maximum current of 55A. So, my excursion breaker current is 55A ÷ fourscore% = 68.75A. The adjacent closest excursion breaker size is 70A.
Here is a list of mutual circuit breaker sizes:
| 6A | 32A | 80A | 200A |
| 10A | 40A | 100A | 250A |
| 16A | 50A | 125A | 300A |
| 20A | 60A | 150A | 350A |
| 25A | 70A | 175A | 400A |
3. Friction match the Wire Size by Current-Carrying Capacity
Now, use the circuit breaker ampere to find the matching wire size by current-carrying chapters. You may utilize Mega Kabel wire current-carrying chapters tabular array or any other wire current-conveying capacity table based on your preference and practicing standards.
In Malaysia, we use MS 2112-3 standards for wires and cables. Otherwise, you lot may use BS 6004 standards which are from the UK or IEC 60227 standards which are also equivalent to both MS 2112-three and BS 6004 standards.
From the above table, I match 70A, which is the circuit breaker ampere, with a 25mm2 wire size. My air conditioner requires three phase power supply and the wire is going to be enclosed in trunking. So, I apply the table to friction match the wire size accordingly.
Notice that the ambience temperature and the usher (wire) operating temperature is stated in the above table. It means that the wire has the stated current-conveying chapters nether these conditions. If the ambience temperature increases, the wire current-carrying capacity volition drop which may crusade you to use a bigger wire size.
You may ask why did I use 25mm2 instead of 16mm2 since the maximum current is merely 55A. It is considering a wire will continue to acquit more and more current until the excursion billow trips. The 70A breaker will allow more current to menstruum than the wire is capable of carrying. If a 16mm2 is connected to a 70A breaker, there is a risk of wire failure.
That'due south why we practice using the circuit breaker ampere to calculate wire size.
4. Check the Percentage of Voltage Drop
Subsequently y'all got the wire size based on the current-carrying capacity, you'll need to bank check the voltage drop to run into if information technology is within an acceptable percentage so that your air conditioners and other pieces of equipment volition not suffer low voltage problems.
Considering wires take resistance, the voltage at the start of the wire is not the same as the end of the wire. In other words, a 415V power supply may be left with only 400V when reaches the air conditioner because there is a voltage drop across the wire.
NEC recommended that voltage driblet should not exceed 5%. For me, I practice limiting voltage drop at 2.5% for optimal performance.
Voltage drop is affected by the wire length. The longer the wire, the greater the voltage driblet. Hence, to check the voltage drop, y'all'll need to approximate the wire length start.
To check the percentage of voltage driblet, detect the voltage drib value using the wire voltage drop table. Again, you may use Mega Kabel wire current-carrying capacity table or any other wire electric current-conveying capacity tabular array based on your preference and practicing standards.
Continuing my example, 25mm2 wire has a voltage driblet of 1.55 MV/A/chiliad. Assume that the wire length is 30 meters, the percentage of voltage drib is calculated as follow:
Total voltage drop = load x voltage drop 10 wire length ÷ 1000
Full voltage drib = 70A x 1.55 MV/A/m ten 30 meters ÷ 1000
Full voltage drib = 3.255V
Voltage drib % = 3.255V ÷ 415V x 100
Voltage driblet % = 0.78%
The consequence 0.78% of voltage drop is well under both my 2.5% and NEC recommended 5% requirements. Hence, 25mm2 wire is suitable for the 55A air conditioner.
If the resulted percentage of voltage driblet exceeds 5%, you'll need to go on trying the adjacent wire size until the voltage drop satisfies the requirement, regardless of the wire current-conveying capacity.
For case, if the wire length is extended to 200 meters, the resulted percentage of voltage drop becomes v.2%. In this case, 35mm2 wire is needed and so that the voltage drop is reduced to 3.7%.
Some standards let their wire/conductor to operate at xc°C instead of 70°C. So, their current-carrying capacity is greater and their voltage drop is lesser.
5. Cheque the Correction Factor
If you lot are sizing wires that somewhen volition be installed in places where the ambient air temperature will exceed or fall below 30°C, you need to apply a correction factor as follow:
| Ambient Air Temperature | Correction Factor |
|---|---|
| 25°C (77°F) | one.03 |
| thirty°C (86°F) | 1 |
| 35°C (95°F) | 0.94 |
| 40°C (104°F) | 0.87 |
| 45°C (113°F) | 0.79 |
To apply the correction cistron, multiply the current-carrying capacity by the corrector factor. For example, the 25mm2 wire has a current-conveying capacity of 89A at 30°C. If the ambience air temperature rises to xl°C, the current-carrying capacity of the same 25mm2 wire becomes 77.43A. Run across Mega Kabel correction factor hither.
If you find the sizing process is as well time consuming, I encourage yous to check out my Pattern Engineer Starter Pack. I included excel calculators for blueprint calculations just similar this one to assistance y'all speed upwardly your work and reduce mistakes.
Factors that Touch on Wire Size
Later going through the 5 steps on how to calculate wire size for air conditioners, it'due south pretty clear that which factors will bear upon wire size the nearly. Nevertheless, let'southward summarize them.
- Load – Wire size depends on electrical current or load.
- Wire length – Long wire length can crusade a bigger wire size.
- Ambience air temperature – High temperature pb to a bigger wire size.
- Wire operating temperature – Loftier temperature allow a smaller wire size.
- Wire fabric – Copper is a ameliorate conductor than aluminium.
- Wire type – PVC, XLPE or armour wire have different specifications.
- Installation – Wires run on perforated cable tray perform meliorate than enclosed in trunking.
Conclusion
When sizing wire for air conditioners, nosotros must utilise the maximum current instead of the rated current or the operating current because air conditioners draw a different corporeality of electric current based on their operating conditions.
Past using the maximum electric current, we are confident that no thing what are the weather condition, the performance of the wire is not compromised. As for fan motors and pumps, using the rated electric current to size wire is usually fine.
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