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This is the serial plate on my electric range. Why are there 2 rows of power usage. One for 6.9 kW and one for 9.3. Is it possible to determine the amperage from this information? I looked up an online manual for this range and it said it was 20 amp , but I believe that was for the gas cooktop version.

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    The two ratings are consistent. For a resistive heating element the power output is proportional to the square of the voltage (ignoring any change in temperature of the element itself). 6.9 x (240 x 240) / (208 x 208) = 9.2. – alephzero Dec 18 '16 at 9:20

Different electrical systems, same range

On the far right, do you see where it says "208Y/120V" in the first row and "120/240V" in the second row? Most electric cooking appliances are designed to run off of two different voltage systems, yours included, and that is why they have two ratings.

Figuring out what you have

The easiest way to figure out which of the two systems you have is to measure at the range receptacle with a voltmeter hot-to-hot. The 120/240V line is the normal split-phase North American residential and light commercial electrical service -- there is 240V (well, 220-250V) between the hots, and 120V hot to neutral. This system is nice for residential work as it supplies both utilization voltages cheaply and allows heating appliances to work at full power -- 9.3kW for your stove.

However, if you measure 208V (or somewhere between say 190-220V) between the hot lines, you have at least two and perhaps all three phases of a three phase wye electrical service, which uses the "208Y/120" line on the range and is found in large buildings, such as high-rises, large institutional buildings, and industrial facilities, although some very large older homes in the South and Southwest use a three phase service due to the size of their air conditioners. Three phase service is helpful for larger buildings as it's a more efficient way of moving power around than single phase or split phase. However, the reduced voltage available at the wall outlet means that heating appliances run at reduced power -- a mere 6.9kW in the case of your stove.

Once you know

Once you know which line to use, simply divide the nameplate power consumption from that line by the line-to-line (hot-to-hot) voltage to get the current draw.

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  • Thanks! I highly doubt I have 208 volts. So I guess that means my range is a 40 amp – Chris Dec 18 '16 at 4:58

If this range is connected to the usual 120/240 V service, then its maximum power is 9.3 kW, which would draw a maximum of 9300 W / 240 V = 39 A. The owner's manual would no doubt say that the circuit should be on a 40-A breaker and of course have wire which is rated for 40 A.

If this range would be on 208Y/120 V, then it would be 6.9 kW. You probably do not have this in a residence. As I understand it 208Y/120 is from a certain kind of 3-phase service which you almost certainly don't have. This would draw a maximum of 33 A and the manual might specify a 40-A breaker.

In actual service the range would almost certainly never be used at its maximum and so it would no doubt work with a smaller breaker, but this would probably be a code violation.

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