220.55

[relbas]

Column C: what does those number mean

 

[bob]

For a range with a max rating of 12 kw, the max continuous demand will not exceed 8 kw.

http://www.ecmag.com/?articleID=8550&fa=article

 

[relbas]

Thank Bob
grate article.

I do have a job that requires 1 wall oven rated 20.8 amp and 1 cook top rated 30.1 amp @208 Volt
if I add them together without the demand I will not have sufficient feeder to the apartment 60 Amp.
If I calculate with the demand It will work but in reality when the customer will turn them both on
I don't think the main will hold.

 

[suemarkp]

Are you sure that's the 208V amps and not the 240V ratings -- a 5 KW range rated for 240V will not draw 5 KW at at 208V, it will draw less.

If the user happened to turn on every burner and the oven, those elements still cycle fairly soon. So it won't be drawing a full 50A for very long. That's why the demand factor is there, no matter what you do these burners cycle.

 

[hurk27]

Are you sure that's the 208V amps and not the 240V ratings -- a 5 KW range rated for 240V will not draw 5 KW at at 208V, it will draw less.

If the user happened to turn on every burner and the oven, those elements still cycle fairly soon. So it won't be drawing a full 50A for very long. That's why the demand factor is there, no matter what you do these burners cycle.

Most small ranges or cook tops, don't have thermostatically controlled elements, and even the larger ones might only have one that might have a thermostat, so at most you might have one of the top elements and the oven that might cycle, the rest will continuously pull power at the setting it is set at, the code takes into account that not all the elements will be run at the highest setting so as you said the wattage in almost all cases will be much less then the appliance rating.

Most top elements will have 2 or three individual heating elements that are configured in series/parallel by the control switch to give the 4 or 5 different heat settings.

 

[Dennis Alwon]

Thank Bob
grate article.

I do have a job that requires 1 wall oven rated 20.8 amp and 1 cook top rated 30.1 amp @208 Volt
if I add them together without the demand I will not have sufficient feeder to the apartment 60 Amp.
If I calculate with the demand It will work but in reality when the customer will turn them both on
I don't think the main will hold.

Are these residential or household ranges. T. 220.55 only applies to household or to instructional programs.

 

[relbas]

those are residential units and the load is in Amperes and 208 V as per manufacture specs.

 

[Dennis Alwon]

Even with the elements on how often are all four elements on high as well as the oven- which is thermostatically controlled. Many standard range we have seen for years are generally 12kw. I have never seen a DP 40 amp breaker trip.