How to calculate required electric connection in KVA

J

Justinâ„¢

Adept
Hello Guys,

Can anybody tell me how can I calculate the required input of an electric connection to a house?

What I want to know is how can I calculate the total requirement by taking in the number of appliances like AC, tube-lights, fans, Microwave etc.

Also, if there is any site where I can get a approximate idea of the volt usage of different appliances?
 
Its written on the appliances themselves.
Watt=VAmp
A 50Watt tubelight consumes 50VA or .05KVA.
4 of these in your home would mean 200Watts and so on.
What is the purpose of this?
 
Justinâ„¢ said:
Also, if there is any site where I can get a approximate idea of the volt usage of different appliances?
Click to expand...

Correct me if I'm wrong but doesn't all household appliances use 230~240V electricity? Some of the heavy duty ones such as an electric geyser/AC/washing machine etc uses the 3Φ power since they draw a lot of power.

Or are you referring to the power draw of the appliances?
 
Hmmm... My bad.

Let me rephrase my question.

I have bought a flat. A max of 15KVA power backup is provided by the builder but I have to decide how much backup I actually need (1KVA is provided, for more I have to pay per KVA). If I want 7 tube-lights, 7 Fans, 3 TVs, 1 Refrigerator and 2 ACs to run on backup, how much KVA backup do I need?
 
^^ Won't solve it.

To make it even more easy:
The builder will install a Miniature Circuit Breaker (MCB) of the total load. My load increases, the MCB will trip. I want to know the required MCB to be installed so that I can use 7 tube-lights, 7 Fans, 3 TVs, 1 Refrigerator and 2 ACs to run without tripping the MCB.

Just to add: I am not an Electrical Engineer (as would be very obvious from my question :p), I also don't know the intricate details I must provide for this question. But I do know that one TV can take more load than another and a 1.5 Ton AC will take less load than a 2.0 Ton AC. So anybody replying can answer in general terms.
 
Here's a rough breakdown -

A tubelight consumes about 50W of power.

A ceiling fan consumes about 50~90W depending on its size and make.

A LCD consumes about 170~190W on an average.

I'm not sure how would one go about calculating the power drawn by a refrigerator/AC since the consumption increases only while the compressor kicks in. An average household fridge consumes about 350~400 units per year.

1 unit = 1kWh.

Therefore 400 units = 400 kWh per year = 400 x 1000 / (365 days x 24 h) = ~45W which isn't true. I think it might consume about 800W. :p

The same holds for the AC as well. A 1.5T AC might consume about 1.5kW. Not absolutely sure on this value though.
 
Justinâ„¢ said:
^^ Won't solve it.

To make it even more easy:
The builder will install a Miniature Circuit Breaker (MCB) of the total load. My load increases, the MCB will trip. I want to know the required MCB to be installed so that I can use 7 tube-lights, 7 Fans, 3 TVs, 1 Refrigerator and 2 ACs to run without tripping the MCB.

Just to add: I am not an Electrical Engineer (as would be very obvious from my question :p), I also don't know the intricate details I must provide for this question. But I do know that one TV can take more load than another and a 1.5 Ton AC will take less load than a 2.0 Ton AC. So anybody replying can answer in general terms.
Click to expand...

well from what i understood u have ur apartment gets a 15kv backup out of which 1kv is supplied to u,which is sufficient for ur 7 tublights can consume as high as 50 to 70watts depending on the brand,fans can consume as low as 45watts upto 70watts(1400mm),tvs if they are lcds based on the size 32" to 46" can consume about 100watts to 200watts,assuming its set to torch mode.if its a 29" crt it will consume about the same as a 46" lcd at torch mode.refrigerator can consume about 160watts and upwards.AC if its 1.5 ton each can consume around 1800 watts.
so if u want to run all of them,them i guess u will need a 30A MCB which can handle around 6600watts,assuming all the said appliances will be running at full load.
 
adder said:
so if u want to run all of them,them i guess u will need a 30A MCB which can handle around 6600watts,assuming all the said appliances will be running at full load.
Click to expand...

Means around (approx.) 7KVA then?

And by torch mode, I assume, you mean maximum brightness?
 
Justinâ„¢ said:
Means around (approx.) 7KVA then?

And by torch mode, I assume, you mean maximum brightness?
Click to expand...

in MCB from the brands i have seen they rate in Ampere so u will need a 30A MCB.

yes maximum backlight in the case of lcd and brightness in the case of plasma/crt.
 
Use the formula KVA = KW / PF and assume PF at 0.6~0.7 (Rough estimate of avg Power factor). I am using 0.66 in the calculation

6600W ~= 6.6kW/0.66 ~= 10KVA.

But also consider that you won't be using using everything at the same time, so make the calculation accordingly.
 
^^ OK.

So here how it goes (all assuming to be highest):

7 tube-lights: 70x7 = 490W

7 fans: 70x7 = 490W

2 TVs: 200x2 = 400W

1 Refrigerator = 500W

2 ACs: 2x1800 = 3600W

Total: 5480W

If I take PF of 0.7, the rough estimate comes out to be: 7.8KVA.

Well, I talked to the Electrical Engineer of our building . He told me 6KVA will be all I need. As I calculated all on the higher side, I think 6KVA is a safe bet then.

Thank you all for your valuable advices/inputs regarding the matter. Was really helpful.
 
Tube lights are 40W each and a typical ceiling fan is 80W though it doesn't make much of a difference in your calculation. Also assuming you wont be using each and everyone of those equipment at the same time, I would say 6KVA is a safe bet.
 
You do understand that you probably wont be using all of this at once? I think you should use 1 ac, fridge, 4 tubelight and 4 fans for calcutation..
 
^^
Exactly.why would you be turning on a fan and ac at the same time :rofl:
The AC part,do already have the ACs and know they'll take that much or just estimating because those look like two very big and very low star rated ACs to me.
A decent 3 star and 1.5Ton AC should be somewhere around 1500-1600 I think and that too at when its strained to the max,external temperature is very high and you want 18'C etc.
Based on these assumptions 7kVA should be a very safe bet.
 
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