advice on wire gauge for built in oven

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Jono604

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Hello,
I 'm in the midst of a kitchen renovation and I'd like some advice on the wire gauge for a built in oven.

The oven is the the only electrical appliance on the circuit and supplied directly from the panel. The cooktop is gas and it's electrical needs will be supplied by a separate 15A circuit.

The oven manufacturer calls for a 30A circuit and lists 7300W in the specs.

I'm inclined to use 10AWG because of the 30A circuit but in some other on-line material I've seen a suggestion that says 10AWG is suitable for 30A appliances with power draw lower than 7200W.

I'm a little bit confused. Does the 7300W rating have any impact on the wire gauge selection of is the 30A circuit the overriding factor?

appliance specs are shown below

thanks
Jonathan



Bosch oven HBL5450UC
http://www.bosch-home.ca/en/products/cooking/ovens/single/HBL5450UC.html?source=browse

Energy source: Electric
Watts (W): 7,300 W
Current (A): 30 A
Volts (V): 240/208 V
Frequency (Hz): 60 Hz
Approval certificates: CSA
Power cord length (cm): 127.0 cm
Plug type: Fixed connection, No plug
 

Dlarrivee

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Well seeing how 30amps * 240 volts would be 7200watts, I think you're sort of crazy and over-thinking this whole thing...
 

Jono604

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"over-thinking" probably.
"crazy" ... I don't know about that. ;-)
I'm just a first time home-owner and first time renovator who's trying to do things the right way.
 

JWelectric

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You admitted to having a lose screw (crazy) in the first sentence of your original post ie: I 'm in the midst of a kitchen renovation

Always install a piece of equipment according to any instructions included in the listing and labeling of the equipment, 110.3 (B) of the NEC

If the installation instructions say 30 amps are what are needed then a 30 amp is what is required to be installed regardless of the math we do. The appliance has been tested by a third party who says that the 30 amp circuit is all that is needed.
 

Leejosepho

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The oven is the the only electrical appliance on the circuit and supplied directly from the panel. The cooktop is gas and it's electrical needs will be supplied by a separate 15A circuit.
I also have an electric oven with a gas top, but both draw power from the 240V connection. So, are you sure the gas top requires a separate 120V circuit?

The oven manufacturer calls for a 30A circuit and lists 7300W in the specs. I'm inclined to use 10AWG because of the 30A circuit but in some other on-line material I've seen a suggestion that says 10AWG is suitable for 30A appliances with power draw lower than 7200W.
Sure. The 10ga wire can be used for anything *up to* 30A, and that means it is also fine with anything drawing less than your oven's possible maximum of 7300W.

Does the 7300W rating have any impact on the wire gauge selection of is the 30A circuit the overriding factor?
No. Volts X Amps = Wattage, and circuits are rated according to amperage while total wattage used is being measured out at the electric meter.
 
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JWelectric

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If volts times amps equals wattage would that not mean that wattage divided by voltage give us amps.

In the equation we know the wattage 7300 and the volts 240 so what would the amperage be? 30.4

Now a quick look at 220.5 (B) Fractions of an Ampere. Calculations shall be permitted to be rounded to the nearest whole ampere, with decimal fractions smaller than 0.5 dropped.

Now we are back to 30 amps just as the instructions called for
 

Jimbo

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Here is the watts breakdown of the components in the oven:
Bake Element Wattages cavity 1 (W): 2000 W
Broil Element Wattages cavity 1 (W): 3600 W
Convection Element Wattages cavity 1 (W): 2000 W


Add that up and it is 7600 watts, but would broil ever run concurrently with bake? Would convection run concurrently with both of the other two???


That is why the "system" is listed as 7300 watts, which is probably at the very high end....and 30 amps is fine.
 

hj

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The circuit breaker determines the MINIMUM wire size, and #10 wire is adequate for a 30 amp breaker. That is ALL you have to know, once you determine that the unit is rated at 30 amps.

Leejoseph; If that is a "hybrid" range, then the 120 control circuit for the cooktop is coming from the 240/120 electric supply. Even electric ovens use 120 for their circuit boards.
 
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Jono604

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Thanks for the feedback everyone.

This all makes sense. I just wanted to be thorough and understand everything before I slap drywall up.

The oven (wall mounted) and cooktop are in different areas so it didn't make sense to have them on the same circuit even if that was allowed.

And to "jwelectric" I guess you're right. I probably do have a screw loose. Not only am I renovating the kitchen, I'm renovating the whole house... as hj and dlarrivee can attest to from my plumbing questions in the other forum.
fun fun fun ...
 

JWelectric

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And to "jwelectric" I guess you're right. I probably do have a screw loose. Not only am I renovating the kitchen, I'm renovating the whole house... as hj and dlarrivee can attest to from my plumbing questions in the other forum.
fun fun fun ...

It won’t be long until you will be ready for one of those pretty white coats that buttons in the back. You know the one with the extra-long sleeves.
 

Leejosepho

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Leejoseph; If that is a "hybrid" range, then the 120 control circuit for the cooktop is coming from the 240/120 electric supply. Even electric ovens use 120 for their circuit boards.
Yes, I understand, and I was just not sure whether the OP had the same or had separate oven and cooktop units. Either way, having a gas top means we can still cook something even while the power is out since our top only needs power for the igniters.
 

Bsperr

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If you have a gas range top, I believe the NEC allows you to put it on one of your 20A small appliance branch circuits, so you shouldn't need to run a 15A circuit just for that (I guess the manufacturer's instructions could trump that though).
 

Electromen

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Run 10/3 with ground "kleenex®". Most of the new ovens have four wires, 2 hot, neutral and ground. Plan on connecting it in a 4" square, 2 1/8" deep metal junction box with 1/2" knock outs. The 10/3 will bit in a 1/2" romex connector. The oven will come with flexible metal conduit. You'll need to buy a 1/2" flex connector, also call a Greenfield connector. If the oven comes with just three wires, 2 hot and a ground, simply do not use the white neutral, cap it off with a wire nut. However most ship with four wires.

ed. sorry you cannot use that other word for wire on here. their lawyers told us so.
 
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Electromen

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If you have a gas range top, I believe the NEC allows you to put it on one of your 20A small appliance branch circuits, so you shouldn't need to run a 15A circuit just for that (I guess the manufacturer's instructions could trump that though).

Do not connect the gas cooktop to a GFCI protected circuit. The ignitor on the cooktop usually trips the GFCI. Connect it to 15 or 20 amp circuit.
 

Electromen

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Where do I go to see this information? Even if it did it wouldn’t be much to reset it.

It's just experience. I've never connected a cooktop to a GFCI circuit. I was called in on a new house to trouble shoot someone else's work. That person had the cooktop connected to a GFCI circuit. The ignitor would trip it every time. I installed a new circuit that was not GFCI protected and it's worked ever since.
 
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Electromen

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I wouldn't want it on a GFCI because if it did trip, gas could fill the room. You have to assume that your clients are going to make mistakes.
 

DonL

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Run 10/3 with ground "kleenex®". Most of the new ovens have four wires, 2 hot, neutral and ground. Plan on connecting it in a 4" square, 2 1/8" deep metal junction box with 1/2" knock outs. The 10/3 will bit in a 1/2" romex connector. The oven will come with flexible metal conduit. You'll need to buy a 1/2" flex connector, also call a Greenfield connector. If the oven comes with just three wires, 2 hot and a ground, simply do not use the white neutral, cap it off with a wire nut. However most ship with four wires.

ed. sorry you cannot use that other word for wire on here. their lawyers told us so.



I never could get kleenex® to conduct electricity very well, When it is wet it does conduct better.
 
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