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Range calculation

Jpflex

Jpflex

Electrician big leagues
Location
Victorville
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Electrician commercial and residential
david luchini said:
You may have missed that 220.55 does not apply to this range.
Click to expand...
I do not have my code book but unless this is being installed in an industrial environment, i believe the code book said 1 range shall be installed to the nameplate rating. HOWEVER, it also says for branch circuits supplying a range table 220.55 is permitted to be used.

Can you explain what is wrong here?
 
david luchini

david luchini

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Jpflex said:
I do not have my code book but unless this is being installed in an industrial environment, i believe the code book said 1 range shall be installed to the nameplate rating. HOWEVER, it also says for branch circuits supplying a range table 220.55 is permitted to be used.

Can you explain what is wrong here?
Click to expand...
220.55 says Electric Cooking Appliances IN DWELLING UNITS and Household Cooking Appliances USED IN INSTRUCTIONAL PROGRAMS.

This range is in a commercial kitchen.
 
Jpflex

Jpflex

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Victorville
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Electrician commercial and residential
retnoc said:
Thank you for that clarification
Click to expand...
220.55 isn’t excluded because of size of load being at 17300 VA but only gets excluded if this is being installed in an industrial or commercial setting such as a restaurant

The original post did not clarify if this was installed in a dwelling or not
 
Jpflex

Jpflex

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Victorville
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Electrician commercial and residential
david luchini said:
220.55 says Electric Cooking Appliances IN DWELLING UNITS and Housed Cooking Appliances USED IN INSTRUCTIONAL PROGRAMS.

This range is in a commercial kitchen.
Click to expand...
The original post did not STATE this range being installed in a commercial location. More info needed
 
Jpflex

Jpflex

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Victorville
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Electrician commercial and residential
LarryFine said:
I wouldn't go that light in a commercial kitchen. I'm still at the full 100a circuit.
Click to expand...
Wire up to 17300 VA then. It’s best to go larger than minimum and post did not specify location initially so 17300. /208 = 83.17 i

Wire:
83.17 i x 125% (do we apply continuous load factor?) = 103.96 i = # 2 AWG THHN?

Breaker:
103.96i = 110 ampere breaker next size up
 
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david luchini

david luchini

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Jpflex said:
That’s not in the original post description but knowing that now i made a new calculation. I don’t have NEC code book on hand so I’m not sure if its accuracy
Click to expand...
The load of the range is 91A @ 208V, single phase. A 100A circuit would suffice.
 
Little Bill

Little Bill

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Tennessee NEC:2017
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Jpflex said:
That’s not in the original post description but knowing that now i made a new calculation. I don’t have NEC code book on hand so I’m not sure if its accuracy
Click to expand...
You know there are more posts and info than in just the OP. You need to read the whole thread before replying to just the OP.
 
T

TX+ MASTER#4544

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Texas
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retnoc said:
Hello everyone,

Long time follower, first time posting.
I've been in the field for over 20 years, but mostly industrial/commercial. I'm getting a lot of contradictory replies from license holders regarding the proper breaker for an electric range, and can use some assistance.

Nameplate is 208v, single phase, 91amps, 17.3kw

Using table 220.55, column C I'm seeing a demand factor of 10,260kw.

When I calculate that by 208v, I'm getting 48amps.

Would I be safe to use a 60amp breaker?

The replies I've gotten have ranged from
60-->80->125amps.

Thanks in advance.
Click to expand...

Hello, retnoc.
Here's the way to calculate your household electric range.

Using the 2023 NEC Code. Section 220.55 refers to T.220.55 " ....for household demand factors and loads..."
See note Number 1 of that table for ".....Over 12 kW through 27kW...." You stated only one range at 12.3kW
Therefore we will have to use Column C titled... Maximum Demand (kW) (see notes) Not over 12 kW.

Therefore, your range is well over that rating so we must apply Note number 1of that table.
Referring again to that note, it says to increase Column C by 5 percent for every additional kilowatt of rating or major fraction thereof for the individual ranges exceeding 17.3 kW. (drop the 3 fraction).

Thus, 17 kW - 12kW = 5 kW at 5 percent 5% x 5Kw = .25 ( 5% for each Kw over 12kW per note number1)
One range from T.220.55 and column C is at 8 Kw.
Must increase that 8 Kw x .25 so multiply the 8 Kw x 1.25 = 10,000 Va or kW or 8,000 x 1.25 = 10,000 W or Va.

I put a number 1 in front of the .25 (1.25) thus the 1 is a hundred percent of the 8kW from Column C plus the 8,000 watts rating for one range.
Obey Ohm's Law, 10,000 watts/ 240 volts =41.66 amps or 42 amps.

Using romex or type NM and the ampacity from T.310.16 in the 60 degree column it requires a 6 AWG at 55 amps.

Table 240.6(A) list a standard size to be a standard 45 amp OCPD. Check Section 334.80 Ampacity.

As to why I did that, take a moment and read that section for using the 60 degree column of T.310.16, the final ampacity for type NM.

Thanks for reading
TX+ MASTER #4544
 
roger

roger

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TX+ MASTER#4544 said:
Hello, retnoc.
Here's the way to calculate your household electric range.

Using the 2023 NEC Code. Section 220.55 refers to T.220.55 " ....for household demand factors and loads..."
See note Number 1 of that table for ".....Over 12 kW through 27kW...." You stated only one range at 12.3kW
Therefore we will have to use Column C titled... Maximum Demand (kW) (see notes) Not over 12 kW.

Therefore, your range is well over that rating so we must apply Note number 1of that table.
Referring again to that note, it says to increase Column C by 5 percent for every additional kilowatt of rating or major fraction thereof for the individual ranges exceeding 17.3 kW. (drop the 3 fraction).

Thus, 17 kW - 12kW = 5 kW at 5 percent 5% x 5Kw = .25 ( 5% for each Kw over 12kW per note number1)
One range from T.220.55 and column C is at 8 Kw.
Must increase that 8 Kw x .25 so multiply the 8 Kw x 1.25 = 10,000 Va or kW or 8,000 x 1.25 = 10,000 W or Va.

I put a number 1 in front of the .25 (1.25) thus the 1 is a hundred percent of the 8kW from Column C plus the 8,000 watts rating for one range.
Obey Ohm's Law, 10,000 watts/ 240 volts =41.66 amps or 42 amps.

Using romex or type NM and the ampacity from T.310.16 in the 60 degree column it requires a 6 AWG at 55 amps.

Table 240.6(A) list a standard size to be a standard 45 amp OCPD. Check Section 334.80 Ampacity.

As to why I did that, take a moment and read that section for using the 60 degree column of T.310.16, the final ampacity for type NM.

Thanks for reading
TX+ MASTER #4544
Click to expand...
You need to read the other posts in a thread. The OP's installation is in a commercial kitchen so 220.55 does not apply.
 
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