Range Question

[dwellselectric]

I have a well perhaps a silly question. Now we haven't roughed a house in god knows how long. For the reason that my boss lost about ten grand from a GC and now we do small remodels and a ton of old work. Dont get me wrong the work is great and we are very busy. But I was talking to another electrican in class the other night and he asked me a question and I guess I got the answer wrong. He said what size wire do you generally pull for an electric range. If I recall we used to wait to see what range the HO got and run what the range requires. He said that was not the right thing to do. I guess he said your supposed to pull a 6/3? He said that was a rule of thumb. Is this true? Sorry if its a stupid question. Just wondering what you guys do when pulling for a range.

 

[nyerinfl]

I pull 6/3 if unknown. The reason is incase their is any LED or anything requiring a neutral. If it is straight burners (resistive loads) a 6/2 would do. Pulling an 8 guage you could short yourself on the amperage, but 8 is 'usually' good for smaller ovens, even then an 8/3 would be the safe choice.

 

[mdshunk]

An 8/3 NM on a 40 amp breaker will do 90% of the typical freestanding ranges. I generally always pull a 6/3 just in case I get ambushed with a bigger range that needs the 50 amp OCPD. It is also safe to say that every range nowadays will need the neutral, so pulling anything besides a 3-wire is just silly.

 

[Dennis Alwon]

An 8/3 NM on a 40 amp breaker will do 90% of the typical freestanding ranges. I generally always pull a 6/3 just in case I get ambushed with a bigger range that needs the 50 amp OCPD. It is also safe to say that every range nowadays will need the neutral, so pulling anything besides a 3-wire is just silly.

Although I agree with you, I have wired a Viking or a Wolf range that was straight 240V-- no neutral.

 

[mdshunk]

Although I agree with you, I have wired a Viking or a Wolf range that was straight 240V-- no neutral.

Point taken, but I think that even if I knew that such a range was going to be installed as original equipment, I'd still pull a 3-wire without thinking twice about it.

 

[electricmanscott]

I run a 6/3 to a range. Covers all the bases. I am working on a remodel where they had a 10/3 fed from 30 amp fuses on a range with a nameplate of about 53 amps I believe. They've never had a problem.

 

[frizbeedog]

What would frizbeedog doo?

What would frizbeedog doo?

6-3 definitely.

 

[Dennis Alwon]

I'd still pull a 3-wire without thinking twice about it.

That is exactly what I did. I was just trying to enlighten you to the fact that there are ranges out there that have no neutral.

 

[iaov]

I'm waiting for a HO to make up there minds right now on the range. I'm not going to pull a 6/3 unless I have to. I'm spending my money so if I can get away with an 8/3 I will.:smile:

 

[Cavie]

8/3 is the standard here. I found lots of ranges that called for 6/3. When I brought it up I was told not to look at ranges on the final. I was told "let the contractor worry about it." On the Mega houses it was not a problem.

 

[dwellselectric]

Thank you guys for your answers I guess I will follow suit and pull a 6/3 :grin:

 

[electricmanscott]

I'm waiting for a HO to make up there minds right now on the range. I'm not going to pull a 6/3 unless I have to. I'm spending my money so if I can get away with an 8/3 I will.:smile:

Can you some do some work at my house? I could use some free electrical work around here.

 

[jrannis]

I have a well perhaps a silly question. Now we haven't roughed a house in god knows how long. For the reason that my boss lost about ten grand from a GC and now we do small remodels and a ton of old work. Dont get me wrong the work is great and we are very busy. But I was talking to another electrican in class the other night and he asked me a question and I guess I got the answer wrong. He said what size wire do you generally pull for an electric range. If I recall we used to wait to see what range the HO got and run what the range requires. He said that was not the right thing to do. I guess he said your supposed to pull a 6/3? He said that was a rule of thumb. Is this true? Sorry if its a stupid question. Just wondering what you guys do when pulling for a range.

Answer. AVOID WORKING FOR GCS!
6/3

 

[gndrod]

Thank you guys for your answers I guess I will follow suit and pull a 6/3 :grin:

Good decision...for those who pull 6 Cu, but pulling 8 is a gamble on what the AHJ may enforce when applying 210.19(A)(3). This issue was hotly argued last year on this forum about using Table 220.55 Demand Factor and overall service Loads calculations as a means of determining conductor sizing.

Wording has been revised in the 2008 Branch-circuit rating Article 422.10(A) as it now states, "Branch circuits and branch circuit conductors for household range and cooking appliances shall be permitted to be in accordance with Table 220.55 and shall be sized in accordance with 210.19(A)(3)." Using the NPR as a sizing basis is probably a good choice in determining the range BC sizing, providing it is the final installation. I know from past use of 8 awg for ranges, the AHJ can tag using 220.55 for sizing as a violation. Some high-end installations use commercial grade equipment with 16kW+ amenities. FWIW, I would not take a chance wiring 8 Cu for a range unless it is spec'd on the plans. rbj

 

[LarryFine]

You can often tell by the house what is likely to be installed. A 1K-s.f. house isn't likely to receive a range requiring 50a. Jf the cabinet opening is 36" or larger, a 50a circuit is a good bet.

 

[haskindm]

Wording has been revised in the 2008 Branch-circuit rating Article 422.10(A) as it now states, "Branch circuits and branch circuit conductors for household range and cooking appliances shall be permitted to be in accordance with Table 220.55 and shall be sized in accordance with 210.19(A)(3)." Using the NPR as a sizing basis is probably a good choice in determining the range BC sizing, providing it is the final installation. I know from past use of 8 awg for ranges, the AHJ can tag using 220.55 for sizing as a violation. Some high-end installations use commercial grade equipment with 16kW+ amenities. FWIW, I would not take a chance wiring 8 Cu for a range unless it is spec'd on the plans. rbj

220.55 States that for ranges up to 12KW you calculate the load as 8KW. 8KW is 40-amps @ 240-volts. Unless the range exceeds 12KW nameplate there is no reason to install a branch circuit larger than 40-amps. You may wish to install a 50-amp circuit "just in case", but you need to stop somewhere. You could also install a 100-amp circuit "just in case" the homeowner wants to install a commercial type range. If the homeowner could not tell me what size range they planed to install I would note on the contract that I had wired for a 12KW maximum range. If they then wanted something different, it was a change order.

 

[gndrod]

220.55 vs 210.19

220.55 vs 210.19

You can often tell by the house what is likely to be installed. A 1K-s.f. house isn't likely to receive a range requiring 50a. Jf the cabinet opening is 36" or larger, a 50a circuit is a good bet.

Hi Larry,

I agree with you in dingbat housing, but in condo's that could be a surprise when options and clients are involved. Personally have had the experience of being tagged on final. There are 30" wide AER's with bread cookers that are specifically manufacturer spec'd for 6 Awg, and that's where installing 8 Cu is too marginal for guessing what's going in there if plan legend isn't spec'd.

Hi Haskindm,

The 220.55 uses the word 'calculate', the 2008 Article 422.10(A) has been revised to use the word 'size' in accordance with 210.19(A)(3). What is your interpretation on why the CMP made that change? Just curious. rbj

 

[haskindm]

The 220.55 uses the word 'calculate', the 2008 Article 422.10(A) has been revised to use the word 'size' in accordance with 210.19(A)(3). What is your interpretation on why the CMP made that change? Just curious. rbj

I don't see that the word change did anything except make you go through several code sections to come back with the same answer we had to start with.
210.11 instructs you to supply branch circuits for appliances with an ampacity as calculated in 220.10.
220.10 specifies that you use table 220.55 to calculate a range load.
422.10 also specifies that 220.55 is used to calculate the load but also tells you to "size" it according to 210-19(A)(3).
210.19(A)(3) specifies that the branch circuit must be adequate for "the load to be served" but does not make any other statement about how that load is determined. It does go on to say that the circuit must be rated 40-amps for any range rated 8 3/4 KW (8750 watts) OR MORE. So without any instruction to the contrary, it seems that 220.55 is again used to "size" the branch circuit.
All that brings us back to sizing the branch circuit to serve the load as calculated using 220.55. We are not presented with an alternative. If the intent was that the branch circuit must be sized to provide the full nameplate, it would say so. It seems clear to me that the 220.55 value is what we are to use.
220.55 clearly shows that the "load" for a single 12KW range is calculated to be 8KW. 8KW at 240 volts is about 34 amps, but since 220.19 tells us that a 40 amp circuit is required for a range rated at 8-3/4 KW OR MORE, we must install a minimum 40-amp circuit. Then 210.24 allows us to install a 50-amp receptacle on a 40-amp circuit.
At this point everyone should be happy and all of the applicable sections of the code should be satisfied.

Whew! I don't know about you, but I am exhausted. NOTHING should be this complicated.

 

[gndrod]

good synopsis

good synopsis

I don't see that the word change did anything except make you go through several code sections to come back with the same answer we had to start with.

Whew! I don't know about you, but I am exhausted. NOTHING should be this complicated.

Haskindm,

That was a great effort on your part. I guess we are still in the dark as why the change was made to 422.10(A) 'sizing' conductors for a reality of the real world of wiring. It all comes down to the AHJ interpretation and call. Checking the range mfr recommended hookup specs on final can be disaster. Thanks, rbj

 

[electricmanscott]

I don't see that the word change did anything except make you go through several code sections to come back with the same answer we had to start with.
210.11 instructs you to supply branch circuits for appliances with an ampacity as calculated in 220.10.
220.10 specifies that you use table 220.55 to calculate a range load.
422.10 also specifies that 220.55 is used to calculate the load but also tells you to "size" it according to 210-19(A)(3).
210.19(A)(3) specifies that the branch circuit must be adequate for "the load to be served" but does not make any other statement about how that load is determined. It does go on to say that the circuit must be rated 40-amps for any range rated 8 3/4 KW (8750 watts) OR MORE. So without any instruction to the contrary, it seems that 220.55 is again used to "size" the branch circuit.
All that brings us back to sizing the branch circuit to serve the load as calculated using 220.55. We are not presented with an alternative. If the intent was that the branch circuit must be sized to provide the full nameplate, it would say so. It seems clear to me that the 220.55 value is what we are to use.
220.55 clearly shows that the "load" for a single 12KW range is calculated to be 8KW. 8KW at 240 volts is about 34 amps, but since 220.19 tells us that a 40 amp circuit is required for a range rated at 8-3/4 KW OR MORE, we must install a minimum 40-amp circuit. Then 210.24 allows us to install a 50-amp receptacle on a 40-amp circuit.
At this point everyone should be happy and all of the applicable sections of the code should be satisfied.

Whew! I don't know about you, but I am exhausted. NOTHING should be this complicated.

This is why I just run a #6 and install a 50 amp breaker and receptacle...too much reading otherwise.