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How to tell how many amps

Posted by lyban (My Page) on
Fri, Nov 6, 09 at 23:44

I bought an older home (1945) that has a lot of renovations on ground floor and basement but none on top floor.
The electrical ciruit box is on the ground floor and here is my stupid question.
How can I tell how many amps I have. I am hoping that this is now 200 amps but I want to make sure.


Follow-Up Postings:

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RE: How to tell how many amps

If you are the owner of the home, you can call the utility company and get the highest reading in kW for your meter.
The other thing you can do is a load study, basically go around your house and add all the appliances, HVAC units, fans, plug-ins, etc.. This will be a little off, but it will also give you the worst case scenario of the actual load on a panel should ALL electrical devices be on at the same time.
You will see the actual load on a house is almost exactly half of what the load study is.


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RE: How to tell how many amps

If you have a single main breaker it should have a number like 100, 150, or 200 on it and this is the maximum combined amperage that you can draw from all your loads for any significant period of time.

Note that you have two 120 volt hot legs and each one can supply that many amps.

Since you won't have everything on at once, the sum of the other breakers in the panel will ordinarily add up to more than the main breaker.

Going around the house adding up loads that COULD be turned on doesn't tell you if your service can actually supply them all at once. If the main breaker is labeled, that will tell you.


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RE: How to tell how many amps

Thanks for the help. I will see if I can figure it out.


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RE: How to tell how many amps

Look at the main disconnect breaker or fuses. If you have a double 100 amp breaker then you have a 100 amp service. You do not add the two breakers together for 200 amp.


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RE: How to tell how many amps

Thanks again everyone.
I do have 200 amps I now know.


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RE: How to tell how many amps

i have a building that has 2 60amp breakers for the heat and air.1 30 amp for 220 outlet all other breakers for lights and outlets are 20 amp.we are wanting to make the building a rental. will have to add stove,hot water heater,dryer,and add for well pumpand holding tank.also dishwasher.how can i tell if i can add all this in the box and be ok


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RE: How to tell how many amps

Starting a new thread would have been the best way to begin. In addition to that, more information is necessary. The fastest thing to do might be to post a picture of your main service panel both with the meter, and with the panel open. People will need to know what the main breaker is and how many open, unused breaker slots there are. If you can read the previous posts in this thread, you will see that there is already a lot of information that will let you approximate your need and what the capacity of your current service is.


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RE: How to tell how many amps

"i have a building that has 2 60amp breakers for the heat and air.1 30 amp for 220 outlet all other breakers for lights and outlets are 20 amp.we are wanting to make the building a rental. will have to add stove,hot water heater,dryer,and add for well pumpand holding tank.also dishwasher.how can i tell if i can add all this in the box and be ok"

Start a new thread.

But, FYI, adding up the breakers in a box does not tell you anything.


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