RANGE CIRCUIT PROTECTION CALCULATION

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Frank A

Member
Location
Maracaibo, Zulia, Venezuela
I need to install a range circuit for a dwelling unit.

According to the NEC, range circuits in dwelling units have to be sized 5000VA; divided by 240VAC it will be 21Amps.

For sizing the CB should I use the 21amps (25A CB), or should I multiply it by 125% (21A x 125% = 26.25A --> 30A CB)?
 
kwired

kwired

Electron manager
Location
NE Nebraska
Frank A said:
According to the NEC, range circuits in dwelling units have to be sized 5000VA;
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Where are you getting this from?

As already asked, what is the rating of the unit in question?

You can apply demand factors from table 220.55, but it is based on the rating of the unit.
 
J

JFletcher

Senior Member
Location
Williamsburg, VA
Frank A said:
It's an old range. The plate is off. But I've found that, normally, every burner consumes 1,500VA approximately. So, 1,500VA x 4 = 6,000VA. But they're not used at the same time very often.

What do you think?
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What cord is on it? Many older cord and plug ranges have a 40A cord with 3 prong plug to a 50A tombstone (wall mount NEMA 10-50R) receptacle connected with #6 SE to a 40A breaker. If you run 6/3 NM (you have to run 4 wire), you are gtg for any ranges up to 50A
 
kwired

kwired

Electron manager
Location
NE Nebraska
Frank A said:
It's an old range. The plate is off. But I've found that, normally, every burner consumes 1,500VA approximately. So, 1,500VA x 4 = 6,000VA. But they're not used at the same time very often.

What do you think?
Click to expand...
Is there an oven or is it just a cook top?
 
Dennis Alwon

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
8.8 kw range can be wires as 8kw. This is from Table 220.55 for a residence.

Frank are you licensed to do this work?
 
F

Frank A

Member
Location
Maracaibo, Zulia, Venezuela
JFletcher said:
What cord is on it? Many older cord and plug ranges have a 40A cord with 3 prong plug to a 50A tombstone (wall mount NEMA 10-50R) receptacle connected with #6 SE to a 40A breaker. If you run 6/3 NM (you have to run 4 wire), you are gtg for any ranges up to 50A
Click to expand...

Exactly. It has a NEMA 10-50P Plug; 50Amps. But it has been unused for a couple of years and the client wants it back to work.
 
kwired

kwired

Electron manager
Location
NE Nebraska
Frank A said:
I found the info. It's a 8.8kW Range. What should I do? Follow the Code's 5,000VA for ranges or just use the 8.8kW to size the CB?
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Again where are you getting 5000VA from. Dennis mentioned 5000 for dryers.

You may possibly calculate 5000 from table 220.55 depending on demand factor allowed and your unit rating, but I see nothing that is outright 5000.
 
F

Frank A

Member
Location
Maracaibo, Zulia, Venezuela
kwired said:
Again where are you getting 5000VA from. Dennis mentioned 5000 for dryers.

You may possibly calculate 5000 from table 220.55 depending on demand factor allowed and your unit rating, but I see nothing that is outright 5000.
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Yes, you're right. I got confused with Dryers. Thanks for hightlight that. I now understand how Ranges should be calculated.

Thanks.
 
Dennis Alwon

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Frank A said:
Yes, I'm. Just adapting to the NEC.

I now know how to properly calculate range circuits.

Thanks.
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HAha-- I have to laugh (not at you).. Range calculations can be very tricky. Even calculating a range rated 14kw is not as simple as it looks and then when you get into range of different kw like --- 5 ranges rated 9kw, 10 kw, 12, kw &16 kw.... Not as easy as it looks
 
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