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Please help me figure out amperage for the oven

Posted by tunafish76 (My Page) on
Wed, Dec 26, 12 at 18:45

A newbie needs some help here. I'm puzzled by the instruction manual of the oven I got. The oven in question is kuppersbusch 9800.5MX. it has a 3 wire 240 volt connection, red grey and a green/yellow. My understanding it could be wired with a 2 wire and a ground 240 single phase service. the color grey and not black for the wire is my first concern. The conduit coming from the oven has 14GA wires. The "Maximum Power" listed on the oven is 3850W. 240V, 60Hz. the instruction says the oven "is run on a industry low 15A service" and here is where I'm puzzled again. If I calculate the amperage using the ohms law it comes to 3850/240=16A. Why do they say the fuse amperge is 15A? Because of NAC table 220.55 listing the demand for this type of ovens at 80%??? Bottom line is it safe in your opinion to put it on the 15A breaker? I was going to run a dedicated circuit using 12-2 romex tot he junction box (just in case i would need a 20A in the future.
2. I also have thermador steam oven rated at 240V/15A. What breaker do I need for its circuit - 15A?
3. I'm replacing my electric range with a gas range so i will have a free 40A dedicated circuit. NEC says that you can branch circuit wall ovens - is it wise/safe to use this circuit and tap two 12-2 wires into it for my above ovens, or is it better to run 2 additional individual circuits and leave this 40A as is. I was just wondering if a 15A oven shorts would it be enough to trip 40A breaker? thanks a lot

Follow-Up Postings:

RE: Please help me figure out amperage for the oven

1.) Page 5 of the installation manual says the oven requires a 120/240v, 3-wire with ground circuit fused at 15 amps. The manual also says 3.6kW (3600 watts / 240 volts = 15 amps). In any case, you'll need 3 wire plus ground cable. You might want to give the German engineers a call and see if they have any explanation. ;-)

Frankly the "industry low 15 amp" stuff sounds like a bunch of marketing bovine defecation to me. Smaller wire is a little cheaper but watts are watts.

2.) A double pole, 15 amp breaker.

3.) Not sure about that one. Ron or Pete will be along soon.

RE: Please help me figure out amperage for the oven

Thanks for the reply, Mike. The 3 wire with ground was a 9800.0MX in 9800.5MX they went with 3 wires (go figure) and the manual that has infor for UK and Ireland only. Since it clearly says 60Hz and has USA on the box I assumed the stove is made for US market. Emailed to Germany already to no avail. USA rep said "people put them on different breakers" I just hope this darn thing cooks well when I hook it up. Otherwise it is pain in a rear

RE: Please help me figure out amperage for the oven

From what I saw this oven is expensive and one would hope you'd get a bit more support from the manufacturer. Given the information you have, I'd probably use 12 gauge wire and a 20 amp breaker. You could start with a 15 amp breaker and see if you experience any nuisance tripping and then switch to a 20 amp if necessary (using 12 gauge wire to run the circuit). Breakers aren't very expensive.

RE: Please help me figure out amperage for the oven

I'm not going to search for you, but I seem to remember someone here having essentially the same question not too long ago. That is, installation of two Gagg ovens with an existing single oven/range circuit in place. I don't remember the consensus.

RE: Please help me figure out amperage for the oven

You could (if you complied with other requirements) tap a 50A range circuit for multiple units. This however is only 40A.

RE: Please help me figure out amperage for the oven

they left the us market, therefore the customer service is not top notch if it ever was. I will try to do exactly what you suggested. After all NEC table does list demand factor at 80% for the ovens less then 8kW

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