What else do you have in the house that is electric? water heater? furnace? AC?
So far you have not given me a reason why you would need to upgrade from a 150 amp.

Trying to get pricing over the Internet is almost an exercise in futility because rates can vary so much, even within the same town. Not to mention it's near impossible to give an accurate estimate without actually seeing the scope of the work. Find three licensed electricians in your area and ask for estimates. Make sure you clearly spell out the scope of the work so you are comparing apples to apples.

If you think 150 amps is bad, you ought to see homes with 60 amp service. Of course, they have gas heat and cooking and were built with no air conditioning. ;-)

I too am wondering about this part of remodelfla's posting:
how this home ever ran on 150 amps when appliances alone seem to eat more then this up.

Please correct me if I'm wrong. If the induction cooktop is drawing 50amps (let's say all burners running at max), and the wall oven is drawing 50amps (cooking my pies), then I'm using up 100amps, and have 50amps remaining for any other appliances, right?
(150amps minus 50amps minus 50amps = 50amps left).

So then, if I'm also running four baseboard heaters at 20amps each (= 80amps total), then I've topped out my 150amps and something's going to trip.

Is that technically the way it works to add up the amps?

Thanks in advance!

There are two things that you may not be aware of in sizing the electric service. First, you get two 120 volt lines that can go up to 150 amps each. That's 300 amps of 120 volts (if well distributed) or 150 amps of 240 volts, or some combination. Kitchen ranges, water heaters, and whole-house air conditioners are 240V and use their 30 or 50 amps from both hot legs. The lights and small appliances use 120 volts so each sucks from one of the hot legs and it doesn't add up so fast.

The other thing is load diversity. The total of all the branch circuit breakers can be much more than 150 amps because not everything is usually on at once. This even applies to cooking appliances. You usually don't run the oven and every burner on high at the same time. That's how they can give you a combination appliance with only a 50A circuit.

You need to do a load analysis using the standard rules to see what your service need really is.

la koala is better articulating what I was trying to say.

The entire home is electric. AC, water heater, pool pump, everything. You figure we run the A/C constantly about 9 months out of the year. DH wants to draw about 30amps to his shop on the far end of the property. It's not the "how to" part of him doing this that concerns/confuses me... it's the me not understanding how this adds up to adequate and also goes back to my personal need/concern about my induction cooking.

If one induction range requires 50 amps; why do I need almost twice that for a cooktop and UC oven installation when they perform the same function. Why isn't there some kind of device that would allow both appliance to share the one plug if the 50 amps would be adequate to run both?

Hi billhart, thanks for the details about the relationship between the voltages and the available amps. That was a big piece that I was missing.

Hi remodelfla,
Can you post what the voltage usage/requirements of both the induction cooktop and oven are? Based on what billhart posted, to really calculate the expected load, both the voltage and amp requirements are needed.

I don't know the answer to your other question about why the requirements seem to be greater to have two separate appliances (cooktop and undercounter oven) vs a single free-standing range (cooktop & oven combined). I mean, usually, if the manufacturer says those are the requirements, that's the bottom line. On Thanksgiving Day, you can bet that I'd be using all burners and running the oven at the same time!

A cooking appliance on a 50 amp circuit does not necessarily mean that the appliance will ever draw 50 amperes. The maximum possible current draw could well be less. And conventional ovens often cycle the element(s)on and off as the means of temperature control. So full loads are typically for short intervals and intermittent. And if the household is involved in intense cooking, other electrical usages probably are at less than full load at that moment. Have a qualified electrician do the service calculations per NEC Article 220.

For instance: Kenmore/Electrolux induction range:
Max. Amp Load: 50
Min. Amp Load: 50 amp circuit min.
Power Source: Electric
Configuration specs:
No. of Elements/Cooking Zones: 4
Element Configuration: Standard: 1-7 in., 2300/1800 watts Power Boost,Standard: 1-6 in., 1500/1200 watts Power Boost,Large: 1-10 in., 3200/2400 watts Power Boost,Large: 1-8 in., 3000/2200 watts Power Boost
Element Type: Radiant
Type: Ceramic-glass
Oven(s):
Oven(s), Number of: 1
Upper/Single Oven Configuration:
No. of Oven Racks: 3 w/intergrated handles
No. of Rack Positions: 4
Bake Element: 2500 watts
Broiler Element: 4000 watts
Capacity: 4.2 cu. ft.
Cleaning Method: Self-cleaning
Convection Element: 2500 watts
Convection Type: Variable speed convection w/ convection conversion

Separate same sized induction cooktop and oven installed under the counter:

30" induction top:
Power Cable Location: Middle Right Rear
Amps @ 240/208 Volts: 35 Amps
Connected Load Rating - 240/208 Volts: 7.4/6.7 kW
Electrical Requirements: Single phase 3- or 4-wire cable, 120/240V or 120/208V, 60 Hz, fused on both sides of line with ground

Wall Oven installed U/C:
Bake Wattage: 1,500 Watts
Broil Wattage: 4,400 Watts
Convection Wattage: 2,500 Watts
Power Requirements
Requirements: 120/240V 60 Hz, 4 Wire, 50 amp Circuit

I understand what you're all saying and I don't mean to beat a dead horse but it still makes no sense to me. I understand why... but not how come.

The "how come" is not absolutely necessary. And it certainly is not incumbent on others to voluntarily expend whatever effort is necessary to bring about the understanding of "How Come". Perhaps your local community college has courses that will help.

Of course it's not bus driver and I by means meant to imply that I had expectations of others responsiblity. I appreciate that time and effort expended to answer my post. Thank you.

remodelfla, there are a bunch of ways to "calculate" service needs. Half of them are complicated and the other half are nonsense.

A service greater than 100A is very uncommon in my region. There are a few on newer houses but most residences in my area are very, very old. Some have original 60A fuse boxes. I've seen just about every modern appliance you can think of around here, including induction cooktops, double ovens, central air conditioning, and even electric baseboard heat. I don't know anybody who has ever tripped their main breaker or blown their main fuse - except for myself when I conducted an experiment to figure out if I could. This involved running all four burners, both ovens, all the heat, and the a/c, simultaneously, for about a half hour.

Circuit breakers don't just magically trip when you reach their amp rating. There is a "curve". The labeled rating is the current at which the breaker will trip after a defined amount of time with a continuous load. Your instantaneous, short-term load may very well go above that for short periods of time. This is calculated, computed, and engineered by persons having much more education and qualification than you or I.

Devices intended to be "continuous loads" have a labeled rating of 125% (at least) of what they may actually draw. This includes the electric heat mentioned above. You CANNOT figure out how much power something is using or is going to use based on the number written on the breaker handle. A 50A breaker will allow the device to draw UP TO 50A. That device may only pull 20A or 30A. Further, it may not be a continuous load. Who runs all four burners and their oven for three hours continuously, while simultaneously cranking their electric heat to 80 degrees and leaving all the doors and windows open in the middle of January? Nobody that I know!

I grew up in a 3-bedroom apartment with all electric heat, hot water, cooking, and laundry in the apartment. It had a 100A service.

Install what you wish to, and go with it. If you ever trip the main breaker (I'm betting you won't), then it's time to consider a service upgrade.

pharkus... thank you very much for your lay person friendly and encouraging response. I now much better understand the concept and feel more confident in installing whatever my heart desires!

Use this link to determine your service size requirements.

http://www.selfhelpandmore.com general-method-of-dwelling-calculation-2002

joed, thanks for that link! That looks like a useful site.