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Participant

Join Date: Jun 2008
Posts: 3

Electrical Demand Load for an Apartment Building

06/12/2008 8:34 AM

Can anybody help me to calculate an electrical demand load for the apartment in Buenos Aires, Argentina?

The typica apartment is 120 sq. m and it has an electrical cooktop, built-in oven, washer, dryer, refrigerator and microwave. It also has a fan-coil unit with electrical heater.

Thank you

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Associate

Join Date: Jun 2008
Location: Chennai
Posts: 31
#1

Re: salaka

06/12/2008 9:17 AM

Hi,

With these details (ie 120 sq.mm ) amximum deamnd load cannot be calculated. What we require is the Rated Power of each equipment/ Lights to be used.

N.Suresh

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Participant

Join Date: Jun 2008
Posts: 3
#2

Re: salaka

06/12/2008 9:51 AM

Thank you for your reply, I'm not looking for the actual number for KVA. What I want to know is a demand factor that can be applied to each electrical load so I can do my own calculation. I have the copy of Argentinian electrical code, but I cannot read Spanish.

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Power-User

Join Date: Jul 2006
Location: Springfield, Tennessee U.S.A.
Posts: 231
Good Answers: 16
#3

Re: Electrical Demand Load for an Apartment Building

06/12/2008 11:16 PM

I presume you are wiring the apartment for electricity? Or, do you just want to know the demand load of an apartment?

A good start would be to add all of the nameplate loads of the equipment (including the lighting) and use this sum as a reference for the maximum load. This sum will just be a reference for the remains of your calculation.

Without knowing Argentinian code, I cannot give good advice. But I will say this much. It is customary practice to measure all current users while they are operating at "normal" mode and use these numbers for your calculation. When all devices (washer, dryer, hot water heater, stove, heater, microwave, etc.) are running, you need to assess the load demand by each device. Things such as the stove, hot water heater, and lights extract a "smooth" and steady current draw, but things such as washing machines and refrigerators can have a high momentary draw when their motor starts.

Once you know the "normal" running load of each device, add all numbers and that will be your running load for the apartment. The wiring and supply current must be able to handle at least 120% of the running load. This allows devices such as the washing machine or refrigerator to start under load without causing a noticeable current sag. It is a good habit make sure that the running load of all devices never exceeds 80% of the available current. This allows a bit of current to be available for motor starts, and can prevent overheating of the wiring and switchgear.

You should be able to contact the manufacturer of each device and determine the normal running load, as well as the starting load of devices that are equipped with motors. If you cannot find the information in that way, just use an amp meter to test similar equipment that is already installed somewhere else.

Best Regards,

Ing. Robert Forbus

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Associate

Join Date: Jun 2008
Location: Chennai
Posts: 31
#4

Re: Electrical Demand Load for an Apartment Building

06/13/2008 1:32 AM

Hi,

As informed collect the name plate details. The Wattage and the Voaltge and the Current will be required. Otherwise at least two parameters are required. Then Summate the Maximum demand.

N.Suresh

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Power-User
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Posts: 367
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#5

Re: Electrical Demand Load for an Apartment Building

06/13/2008 7:14 AM

From my own years of calculating using NEC (USA) and some of European Codes I know that there is different approach. What are Code requirements and calculation methods in Argentina it seems nobody here knows.

But what about do scan the local code written in Spanish and bring it to this forum? I believe in USA there is a lot of electrical engineers who can translate and comment.

Mr Salaka - you need to spend some time to figure out which paragraphs apply to your problem. The time you spend will enhance your knowledge significantly and maybe you will have next chance to help yourself or other person later.

Good lack!

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Commentator

Join Date: Mar 2008
Posts: 57
Good Answers: 3
#6

Re: Electrical Demand Load for an Apartment Building

06/13/2008 8:45 AM

Calculate the apt. at 27 watts/ sq.m for general use = 3,240 watts.

Small appliances add 3,000 watts = 3,000 watts

Electric cooking add = 10,000 watts

Dryer add = 3,000 watts

Washer add = 950 watts

Fan coil unit add = 13,200 watts

total 33,390 watts

Demand factor

first 3,000 watts at 100% 3,000 watts

The next 3,950 watts at 35% 1,383 watts

Electric cooking, dryer and heating at 100% 26,200 watts

total 30,600 watts @ 250 volts single phase will be 122 amps.

These numbers can be adjusted up or down depending on the actual loads of the cooking, drying and heating equipment

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Guru

Join Date: Oct 2007
Location: Transcendia
Posts: 3374
Good Answers: 94
#7
In reply to #6

Re: Electrical Demand Load for an Apartment Building

06/14/2008 7:39 PM

The rule of thumb is for 120volts single or three phase: 10 amps per thousand watts. The typical room residential circuits fed to a breaker for that circuit will be 15 amps. I myself think in square footage instead of square meters, and am not familiar with 220 AC systems. A hair dryer or coffee maker will draw 10 amps as most are 1000 Watts, for example. The 10,000 Watt electric stove is a bit of a puzzle for me for typical homes in the US fed 220 on a 50 amp dedicated circuit to the electric stove. My work was with movie sets and their needs, and I am not well versed in codes or residential work, and can only give from what I know.

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Power-User
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Posts: 367
Good Answers: 1
#8

Re: Electrical Demand Load for an Apartment Building

06/15/2008 1:40 PM

I understand Argentina has similar power low-voltage system as Europe i.e. 220V/50 Hz. So calculation is very different from USA (At least was when I did it several years ago there).

For home appliances maybe this web will tell you something:

http://www.euromonitor.com/Domestic_electrical_appliances_in_Argentina

Do you have original their National Code? If yes Copy & Paste pages that apply to your problem. There are many el_engineers who can read and translate rules from Spanish to English or even do the calculation similar to those from # 5

Also Search entering e.g.: Argentina Electric appliances

xxx

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Participant

Join Date: Jun 2008
Posts: 3
#9

Re: Electrical Demand Load for an Apartment Building

06/16/2008 4:10 PM

Ladies and Gentlemen:

Thank you for your answers. I contacted the electrical engineer in Buenos Aires with the same question. His calculation runs like this:

2 lighting circuits at 2.25 KVA @ 66% each;

2 receptacles circuits at 2.2 KVA @ 100% each;

Refrigerator/microwave circuit at 2.2 KVA @100%

Cook top, oven, dryer and washer were all taken @ 50% of the nameplate.

Electric heat (in the fan-coil unit) was also taken at 50%.

The calculated sum of all the above loads was taken with 70% demand.

Maybe this can help somebody one day, who knows…

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Anonymous Poster
#10
In reply to #9

Re: Electrical Demand Load for an Apartment Building

01/24/2009 4:48 PM

Hi. I'm a student and this thread helped me a lot! thanks ^_____^

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Users who posted comments:

Anonymous Poster (1); Ing. Robert Forbus (1); Nagarajan.Suresh (2); salaka (2); southern123 (2); They Know! What? Nah! (1); Transcendian (1)

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