Just a general question to all you gurus:

My house was built in 1978. It's your typical tract home and the main breaker panel has a nice fat main double-switch that has 2 large black (#4 gauge I think, could be bigger) copper feeds to it. I have 1, 240 volt circuit that powers the AC unit (which, by the way, appears to be aluminum wire of a large size). I'm going to pull a second 240 line (4 wire, #6 gauge) to power my new GE electric range.

Should I have enough "amperage capacity" to power both lines and the rest of the house? I always assumed that a "modern" home should have plenty of capacity for what I'm trying to do. How do you know what the amperage rating is for the main box, and / or how do you find out what is being supplied from an amperage point of view to your home. Is there a typical standard for homes built after a certain time?

Thanks!

 

Tell us all the numbers on the main breaker handles.

Then tell us:

1. The square feet of the house.
2. Whether the home heat is gas or electric.
3. Whether the water heat is gas or electric.
4. Whether the clothes dryer is gas or electric.
5. The number of tons in the air conditioner.
6. Whether or not you have any other big power draws (swimming pool, hot tub, jacuzzi, welder, kiln, second kitchen, second electric clothes dryer, extra freezers or refrigerators, etc.)

 

You didn't tell us the size of your current service. Look for the number on the handle of your main disconnect breaker.

 

OK, I'll get all that info. (I'm at work right now) I can answer some of your questions and they are:

House is 1580 Sq ft. single story, Gas dryer, Gas waterheater, gas central heating. Don't know the tonnage of my AC unit; will find out and post it later. No pool, spa, welder, etc. Only the AC unit is currently the only 240 volt appliance. I'll look at the main breaker for the numbers. So is it "safe" to say as a rule of thumb that the number on the main disconnect breaker would be close to the amperage rating for the main feed?

Thanks.

 

The number on the main breaker is the size of the panel. Don't add the 2 handles together. If the handles both have 100 on them you have a 100 amp service not a 200 amp service.

 

OK, I have more info: The main is a 100amp breaker. There are a total of 9 physical breakers, 5 are independent doubles; 1, 50amp double; 5, 15amp; and 7, 20amp.

So I guess the obvious answer is a 100amp main because of the 100amp main breaker, yes? And I assume that even though my total breaker amperage number is greater than 100 I'm never pulling 20 or 10 amps on a breaker at the same time.

So then the main question would be do I have enough capacity for an additional 240 volt, 40 amp electric stove circuit? I would think that I do.

Thanks again...Hope these questions don't seem to obvious; I just want to be sure before I dig into this project.

 

I didn't ask about the branch breakers, because that information is irrelevant to this question. I did ask about the tons of air conditioning, because that information is essential. I'll assume two tons for your small house. I'll also allot you one refrigerator, one dishwasher, one garbage disposal, one microwave, one kitchen, and one laundry room.

Assuming your range is just a range and does not also include an electric oven, then your demand load, including the new range, is only 89 amps. So the answer to your original question is that you do indeed have sufficient capacity for this new range. Go for it!

If you want, you could post back with the tons on that A/C and the KW rating of your range (and anything else that differs from my assumptions). This would help refine the answer.

 

Hi John,

Sorry for the "extra" info. Yes, you were correct in your assumptions As for the AC unit I'm not sure what the rating is. (I can't find any tech info on it; it's hard to get to) It's the origional that was installed with the house (1978) and I would guess it is not more than what was necessary. It's not too big physically and your guess as to its rating is probably correct. As for the range according to the "Wiring diagram" paper in the little envlope pocket behind the stove, it shows a "Max kilowatt rating" of 16.0 @ 240Volts with a 40amp "NEC Fuse Rating" (Is that the right info?)

Thanks again for your help and input.