What size circuit breaker for Oven

Hi,

The owners manual for our 240 volt oven says it has a max of 4730 watts. The 2 pole circuit breaker says 30 amps on each half. Is that to big? We have had a couple of heating elements go bad with sparks, bright lights, smoke and everything and the circuit barker did not trip.

thanks
Jeff

 

If you do not know this, you should probably let someone who does do the wiring.

A 30 amp double pole breaker, times the 240 volts will supply up to 7,200 watts.

That is only an oven ? On its own breaker a 30 amp will be fine. An electric stove with an oven (not just a cooktop) usually requires a 50 amp which ill supply up to 12,000 atts, and requires heavier guage wire. It also uses a special outlet so it is not confused with an air conditioner, clothes dryer or whatever.

Amma tellya what, if you do not know what you are doing just pay someone weho does. you cannot trust youtube fro instructions, or books, or even the guys down at the local DIY type store. In fact you can't even trust people out of the phoine book, even if they are licensed, bonded and insured. If you want it done right, tell the electrician himself that you want to see his journeyman's card from the union. Tell the company on the pohone you want to see that.

I know tis would cut me out of the job for you, but so be it. I have a rep locally and people know I can do it, and to code. In fact better than code. But apparently you don't have the luxury of knowing someone local. Otherwise this might have been done for a case of beer or something.

If you do htis yourself, make sure the wire is as big as possible. Also, and more importantly, tighten the screws. I mean tighten them until you think they will breakk, they won't. Also wiggle the wire as you tighten the connections. Sometimes you wiggle it and find it WILL tighten just a little bit more. MAKE SURE IT IS DEAD TIGHT.

When they said loose wires cause fires they were not kidding. Really, you are more likely to have a fire with a loose wire than one that is of a bit too small of a guage. In the former situation the heat is all concentrated at the faulty connection poit, in the latter with the too thin wire it is distributed pretty much evenly through the whole length of the run. Not really safe, but less unsafe than a loose connection.

You can look up AWG ratings on Google for all kinds of specs on this. In fact I have a table of all that somewhere on the PC but will never find it. On the web it gives you the ampacity of all the guages, and you might find one for aluminum wire as well but I think that has been outlawed in the US except for the main lead in. But then that only goes from the meter to the panel and tose fitting are made for it. Don't use aluminum wire inside the house for anything even if it is legal where you live.

 

Sparking and arcing mean nothing to the circuit breaker. Only a short circuit does. It probably simply was not shorting out.

 

[Phil Allison]

sculp

The owners manual for our 240 volt oven says it has a max of 4730 watts. The 2 pole circuit breaker says 30 amps on each half. Is that to big? We have had a couple of heating elements go bad with sparks, bright lights, smoke and everything and the circuit barker did not trip.

** It won't trip unless the current is substantially more than 30 amps and continues over a period of time - while instant tripping needs a current 10 times the nominal rating. Wire fuses are even slower acting.

You faulty element did not cause enough current to flow for enough time.


.... Phil

 

The weird thing is that ever since the heating element burnt out, the on/off switch has been acting flakey.

Jeff

 

[Dan Coby]

On 2/14/2015 3:07 PM, sculptorpro@gmail.com wrote:

Hi,

The owners manual for our 240 volt oven says it has a max of 4730 watts. The 2 pole circuit breaker says 30 amps on each half. Is that to big? We have had a couple of heating elements go bad with sparks, bright lights, smoke and everything and the circuit barker did not trip.

The short answer is that the circuit breaker is there to make sure that
the wire to the oven is not overloaded. The rating of the circuit
breaker is chosen based upon the wiring size. A 30 amp breaker is
commonly used to protect 10 AWG wire.

The circuit breaker is not there to protect your oven.


Dan

 

>"You faulty element did not cause enough current to flow for enough time. "

Plus that fact when that shit happens it usually does not short out, it opens up.

 

[Ron M.]

Completely agree on the use of aluminum wire inside the house. Repaired some wiring once after I was told sparks and smoke were coming from an outlet. They had allowed a family member to wire it up originally. Opened it up and found that dipshit had used aluminum wire. They were extremely lucky not to have burned the house down. Replaced both outlets and the wire with copper. Scares me to think there are people out there doing crap like that.

 

[Jasen Betts]

On 2015-02-15, jurb6006@gmail.com <jurb6006@gmail.com> wrote:

If you do not know this, you should probably let someone who does do the wiring.

A 30 amp double pole breaker, times the 240 volts will supply up to 7,200 watts.

that depends if it's twice 240V or twice 120V



--
umop apisdn

 

[Jasen Betts]

On 2015-02-15, sculptorpro@gmail.com <sculptorpro@gmail.com> wrote:

The weird thing is that ever since the heating element burnt out,
the on/off switch has been acting flakey.

I've seen that happen after a containment failure on a element

If you can get a short between the live end of the element and ground,
unusually high currents can flow which damage the controller.

often this will blow a hole in the element sheath.


--
umop apisdn

 

[Cydrome Leader]

sculptorpro@gmail.com wrote:

Hi,

The owners manual for our 240 volt oven says it has a max of 4730 watts. The 2 pole circuit breaker says 30 amps on each half. Is that to big? We have had a couple of heating elements go bad with sparks, bright lights, smoke and everything and the circuit barker did not trip.

That should be fine.

In the US, the next smaller double pole breaker would be 20A, which is too
small for a 4730 watt load as you're not supposed to exceed 80% of the
current rating for continuous duty loads.

As long as the wiring from the breaker to the oven is properly sized at
10guage or larger, all the connections are solid you should be ok.

Fireworks inside the oven are not good, but won't burn your place down.
Now if your wiring outside the oven goes up on flames, well that's a more
serious problem and that's what the circuit breaker and properly sized
wiring is for- protection if the wiring and not your load itself.