Is the load for a range 12,000 watts or 8000 watts? There is a space for a range but has not been purchased yet, so no nameplate. Ana here is another question. Say the nameplate is 7000 watts, should you wire the outlet to cover the client possibly buying a larger range later?
load for a range
- Thread starter mlnk
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- Location
- Chapel Hill, NC
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- Retired Electrical Contractor
Any range from 8 3/4 kw to 16 kw only needs a 40 amp circuit according to Table 220.55 however some range require a larger size by the nameplate.
We usually run a #6 but in most case a #8 copper will do the trick.
We usually run a #6 but in most case a #8 copper will do the trick.
kwired
Electron manager
- Location
- NE Nebraska
See note 4 of the table - it says you can use the table to come up with a branch circuit load for a single range.
Column C says the load for not over 12 kW range is 8kW. Note 1 says you can increase that by 5% for each kW over 12, this is where it allows up to a 16kW range on a 40 amp circuit.
Yes if you turned on every load in a 16 kW range it will exceed 40 amps, but they won't all stay on long before individual loads begin cycling and then you no longer have all 16 kW running at one time. Just the nature of the loads - they don't all run at once, or if they do it is not for very long.
Column C says the load for not over 12 kW range is 8kW. Note 1 says you can increase that by 5% for each kW over 12, this is where it allows up to a 16kW range on a 40 amp circuit.
Yes if you turned on every load in a 16 kW range it will exceed 40 amps, but they won't all stay on long before individual loads begin cycling and then you no longer have all 16 kW running at one time. Just the nature of the loads - they don't all run at once, or if they do it is not for very long.
Looking at load calculations for dwelling unit ranges, I have seen some people use 8,000 watts and some people use 12,000 watts. Per 220.55 I think the 8,000 is correct for the branch circuit load and the 12,000 should not be used.
Now lets talk about actual wiring. Specifications for some ranges say wire with #6 Copper on a 50 amp breaker. I know in actual usage they will never get near 40 amps, but is it Code legal to install it on a #8 Cu 40 amp circuit?
When you do not know what range will be selected, which is usually the case in a new home, I think #6 should be installed. ( but everybody else seems to be using #8.)
Also, I have installed a large double oven where specs required #6 Cu wire. I upgraded to #6, but would it have been Code legal to use the #8 already in the wall?
Now lets talk about actual wiring. Specifications for some ranges say wire with #6 Copper on a 50 amp breaker. I know in actual usage they will never get near 40 amps, but is it Code legal to install it on a #8 Cu 40 amp circuit?
When you do not know what range will be selected, which is usually the case in a new home, I think #6 should be installed. ( but everybody else seems to be using #8.)
Also, I have installed a large double oven where specs required #6 Cu wire. I upgraded to #6, but would it have been Code legal to use the #8 already in the wall?
- Location
- Connecticut
- Occupation
- Engineer
Depends on the calculation method being used. Assuming 12,000watts is the nameplate rating, for the standard calculation method, either 8000w or 12000w is OK. For the optional methods (220.82 and 220.84) only 12000w should be used.
kwired
Electron manager
- Location
- NE Nebraska
If you want to be nit-picky, I suppose it needs #6 and a 50 amp breaker.
Have you ever seen a 40 amp circuit not be sufficient in the real world?
12kW would be 50 amps, you would need to turn on all elements and in the HI selection to even have a chance at loading it long enough to trip the breaker. Traditional surface elements can run continuously on HI, and you may have slight chance of tripping breaker if you turned all them on HI as well as both bake and broil elements. Many other modern surface elements, especially those "smooth top" designs still have a limit thermostat that will still cycle them even on HI setting.
40 amp breaker with 50 amps of load - not sure exactly how long it will hold, should be at least several minutes I would guess, usually long enough that something has cycled off by then, lowering the load.
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