I am replacing a wall oven. The current model uses gas, but research shows that electric is better, and can be installed without reframing the cabinet. The GE model calls for 120/240v with 20A rating. First question is: if the manufacturer calls for 20 amps, do I go with 20 amps or upgrade to 30 amps? Cauldwell’s book makes a note that an oven, when fully used, may draw more than the rated amps, quoting from a memory.
Second: I’d like to describe the work I plan to do and would like your opinion. I’m not an electrician. When renovating a house, an electrician upgraded the main panel, but I added a few breakers later. My panel is Square D. The work planned will be done in the Murrey panels(my parent’s house), and it has main breaker that shuts off rest of the breakers. I plan to remove 40A breaker (double pole) that supplies power to main entrance wall heater that has not been used. Using the same space, I will get power to new oven with lock out, double pole 20A(or 30) breaker using 10/3 wire. Sounds good so far? Is there anything in what I described, working in Murrey panels or working with 240v system that would call for an electrician, in this case? I am hoping to save a few hundred dollars and upgrade the oven to stainless.
Third, does anybody know of someone in NJ who can repair Chambers gas range?
Thank you to all in advance.
Replies
I used to install appliances for a living and if the specs for the wall oven call for 20 amp 220v, then use 12 guage wire, or you could use 10 guage, but make sure the breaker is still a 20 amp double pole breaker
Craig
Yeah, use the breaker size called for by the manufacturer, but it might not be too dumb to go up a size on the wire, in case the unit is replaced with a larger one down the road.
Seven blunders of the world that lead to violence: wealth without work, pleasure without conscience, knowledge without character, commerce without morality, science without humanity, worship without sacrifice, politics without principle. --Mahatma Gandhi
Thank you all for the replies. I will go with 20A double pole breaker with 12 ga. wires. This will supply only the single wall oven. The range is gas. Again, thanks.
You should use a breaker that matches the current rating of the oven as called out in the installation manual. If it's 20A, then don't go any higher. It's OK to use a larger gauge wire because there will be less voltage drop, especially in a long run. You want power to go into heating the inside of your new oven, not the wire running through the walls.
I disagree. There is no danger in installing a 30-amp circuit and running a 20-amp appliance off it. In that most full-sized electric ranges require 30 amps, if he or some future owner remodels the kitchen he will be able to use that circuit to power a range instead of a small wall oven.
As long as he installs 10-3 with that 30-amp breaker it should meet code. The only question is what kind of plug the 20-amp oven is equipped with. A 30-amp plug does not have the pins in the same configuration as a 20-amp.
I am not sure whether a 30-amp circuit terminating with a 20-amp outlet is legal. It doesn't seem to present a danger of overloading the circuit, but it would be a good idea to check. Code-writers are not always masters of logic....
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
>>I am not sure whether a 30-amp circuit terminating with a 20-amp outlet is legal. It doesn't seem to present a danger of overloading the circuit, but it would be a good idea to check. Code-writers are not always masters of logic
I can't find anything illegal about it in my code book.
When talking about appliances and circuite breaker sizing we tend to forget that the breaker is there to protect the wire, and thus the home, not the particular appliance. A 20a breaker will certinly protect a 10 ga wire well below its' design current limit.
Hubbel has a 120/240v 20a receptical, but since this is a wall cabinet installation, it may be a hard wire.
Dave
While you can run #10 or even bigger you can't install a 20 amp receptacle on a circuit protected by a 30 amp breaker.BTW, to the original poster I would like to see the specs on the oven. Just sounds a little low to me.Table 210-24
>>While you can run #10 or even bigger you can't install a 20 amp receptacle on a circuit protected by a 30 amp breaker
I didn't say that Bill. I said you can use a 20 amp breaker to protect a 10 ga. wire. The breaker will trip on overload conditions long before the maximum wire ampacity is reached (table 310.16 NEC 2005)
Dave
Bill, would that be because a 20-amp receptacle can't take 30 amps of juice? Or just to avoid confusing the HO?
Seems to me any spec-grade receptacle should be able to pass 30 amps of current without overheating. They're all built with solid conductors which are much heavier than 10awg wire. What am I missing here?Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
Confusion and application and long term safety.Now all 15 amd 20 amp receptacles are rated for 20 amp feed through.Thus on 15 amp circuits you can use 15 receptacles.On 20 amp circuits you and use MULTIPLE (and a duplex receptacle counts for 2) 15 amp receptacles or 20 amp receptacles. And the 20 amp receptacle can accept 15 amp plugs.But once you get past 20 amps you need to match the receptacle to the circuit.If you used a 20 amp recpt on a 30 amp circuit some one could plug in 2 15 amp loads and over load the receptacle.If you installed a 30 amp recpt on a 20 amp circuit someone might try to use a 30 amp load and trip the breaker. Thus "encouraging" people to change the breaker to match the receptacle. Which is OK if big enough wire had been run in the first place. But often that would not be the case.
>If you used a 20 amp recpt on a 30 amp circuit some one could plug in 2 15 amp loads and over load the receptacle.How would you plug in 2 15 amp loads on a 20 amp recpt? Or are you talking about downstream in the 30 amp circuit?Thanks, good points and post as always!
"How would you plug in 2 15 amp loads on a 20 amp recpt? Or are you talking about downstream in the 30 amp circuit?"The question was about installing 20 amp receptacle on a 30 amp circuit.If that 20 amp receptacle is of the common duplex types you couple plug in two loads. I picked two 15 amp loads the total is 30 amd thus will not trip the 30 amp breaker. But it is much more than the receptacle is rated to handle (20 amps).
Thanks for the read on that; it makes sense.
I'd like to see code require permanent labeling of circuits on each cover plate. But even so, a lot of people just don't read (or understand it if they do). It would be mostly of use to servicemen and remodelers.Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
I promised myself I would not get into these but I believe he is talking about a wall oven. Started typing before I went back to original post to verify. I thought you normally wire to a box and use the factory whip (metal flex) hardwired into box for this and surface ranges. Also thought you are supposed to use the breaker specified by equipment mfr for single appliance circuit such as this. Certainly nothing wrong with upsizing the wire.
I thought you normally wire to a box and use the factory whip
For a floor range, a plug/outlet connection is required here. But for a wall oven, now that you mention it, I think you're right. So he could install a full-blown 30A circuit against a possible future upgrade, connect the BX to it and be more than good to go. That 20A oven will never pull the capacity of the circuit unless it shorts out somewhere.Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
Sorry about the incomplete information. The oven is single, electric wall oven. It is Bosch brand (I would appreciate any information as to any different electrical requirement it may have due to its European origin, although I assume it is made for US requirement.) It has no convection feature. The manual rates the oven as 120/240 volt, 3350 watts and 14 amps. I found that standard wall ovens all cook at 3000 to 3600 watts and most call for 20 amps.
I had planned to use 20A breaker based on the GE brand requirement. But I will call the Bosch service to find out if I should use 15 or 20A breaker. This breaker sizing has become confusing.
For example, there is a GE model (about 3600 watts) that calls for 20A "minimum". Does this mean for maximum protection, I should go to 30A for GE model? Is Bosch rating of 14A mean minimum required (therefore going to 20A) or using 15A breaker? The manual does not give the breaker size, and I admit I have not read the information tag in the oven, yet. Anyway, thank you again in advance.
Edited 11/5/2006 6:41 pm ET by k1c
The smaller the breaker, the more protection you get for both house wiring and oven parts. However, it may be that 15 vs 20 amps is a wiring option, with the oven not producing as much heat when set up for 15 amps. So it's best to read the install instructions.
Seven blunders of the world that lead to violence: wealth without work, pleasure without conscience, knowledge without character, commerce without morality, science without humanity, worship without sacrifice, politics without principle. --Mahatma Gandhi
Also keep in mind that a breaker is supposed to be sized larger than the max anticipated steady current flow by some percent (around 20% but I don't recall the exact number). For this reason a 14A unit may require a 20A breaker, eg.
Seven blunders of the world that lead to violence: wealth without work, pleasure without conscience, knowledge without character, commerce without morality, science without humanity, worship without sacrifice, politics without principle. --Mahatma Gandhi
You are right.
Recommended circuite loading is 80% of breaker size.
20 amp x .80= 14 amp.
As an aside, breakers normaly trip at 125% of rated size after the surge current has exceeded the built in time delay for start up currents.
dave
Thank you all, and here is a new problem.
I called the Bosch customer service. The answer was that I need 40A breaker, because this oven has a self-clean feature (sorry, I forgot to mention this in my posts). Then I remembered reading, a long time ago, something about self-clean ovens becoming very hot during this cycle because the oven runs at maximum heat for the cleaning period. I can't remember if this was about having enough heat-clearance from the cabinet wall or the breaker sizing.
What gauge wire would I need in this case? #8 ga.?
I still want to do the work myself. I plan to double check with the technician to make sure that he is not talking about range-oven combo unit, or based on a general knowledge and not this oven, although I assume the manufacturer's technician would know the answer. He correctly identified the self-clean feature based on the model number. But I did not talk directly with the technician.
The electrical book I have (1991 edition) shows a diagram which states 5200 watt clothes dryer connected to 30A breaker and 8200-16000 watt range-oven to 50A. Bosch oven (runs?) on 3500 watts for self-clean cycle, although clean cycle may be longer than that of the clothes dryer. Still, 40A breaker seems way too high. Of course, I am imagining these differences in my head as if I were comparing weights in my hands, and I know this can't be. It almost seems like I have to call both electrician and an appliance serviceman to install what I thought was a simple oven.
I looked at the cover plate, at the manufacturer's website specifications and at the seller's (Sears) website specs, and none of them mention the need for 40A breaker.
Anyway, to stop the rambling, I would like to check with you all about the correct size wire I should use for 40A breaker. Again, thank you in advance. I really appreciate your attention.
Yes, you need #8 if the breaker is 40 amps.But that is a strange way to spec it for a heating appliacne.Could you post the model number? I would like to see if I can download the installation information.
Thank you for the reply. The model number is HBL503AUC. It is 30 inch, single electric oven with self-clean mode, no convection. The wiring diagram that came with the oven lists bake, broil and self-clean at 3500 watts each.
The site address is: boschappliances.com and look for ovens, then 500 series.
Guess what, even as I was typing above message, I was talking to the manufacturer's representative. He and the technician double checked the model number and now I am told that a single oven will use 20A. 40A was for the double-oven. I think I will triple-check with the seller's service department.
I will post this message in case you want to pursue this for your benefit.
Again, thank you all and please post anything you think of.
"Guess what, even as I was typing above message, I was talking to the manufacturer's representative. He and the technician double checked the model number and now I am told that a single oven will use 20A. "The installation manual is generic for all of the models.But it does show that this model is 3500 watts, 14 amps.This a 20 amp circuit is right. But if it is practical NOW and access would be hard in the future I would run #10.I knew that that the 40 amps just did not make sense. Now things with large motors (air conditioning) do have completely different rules.But for heating appliances all you need to go with is the watts and that shows a 20 amp circuit.
Thank you to everybody for your advices. I think I have the final answer, and it turns out the answer may have been right under my nose, so to speak. I went to the store and the salesman had a hand-sized binder full of information on all models in the store, and there it was in print: breaker size 20 amps.
Thank you again and again. This post was not only informative, but also a lot of fun.
I knew that that the 40 amps just did not make sense. Now things with large motors (air conditioning) do have completely different rules.
Yeah no shid----- I had a big ol lennox electric toaster ---furnace
Had to 60amp 220 breakers to it
My screwdiver found out later that it had a 3rd 20amp breaker to it----- OOPS missed that one“It so happens that everything that is stupid is not unconstitutional.” —Supreme Court Justice Antonin Scalia
(I would appreciate any information as to any different electrical requirement it may have due to its European origin, although I assume it is made for US requirement.)
Unless you bought it on the 'grey market', your assumption is most probably correct. Grey-market merchandise (stuff imported 'legally' but in contravention of manufacturer's export agreements with their exclusive distributors) might be Euro-standard and give you fits to make it work here. However, more and more manufacturers of electrical appliances destined for a world-wide market build-in small circuits that enable the unit to be switched to run on either 50Hz or 60Hz and some give one the option of 120 or 240 volt operation, too.
The manual rates the oven as 120/240 volt, 3350 watts and 14 amps. ...This breaker sizing has become confusing.
Just remember that a breaker rating is the maximum amount of amperage which the breaker will allow to pass through itself before it 'breaks' the circuit and cuts off the power to the wiring in the walls.
Therefore, you must use a breaker rated for at least the maximum total amperage rating of the appliance(s) that you plan to power from that circuit.
You may use a breaker rated higher than that, and it will work fine and be safe...AS LONG AS YOU ALSO USE WIRE FOR THAT CIRCUIT RATED AT LEAST AS HIGH AS THE BREAKER.
In other words, in general:
It's okay to use a 20-amp breaker with #12AWG wire to power a 14-amp appliance. You may not use a 20-amp breaker with 14-gauge (or smaller) wire.
It's also okay to use a 30-amp breaker with #10AWG wire (copper only; for aluminum you must use #8) to power the same 14-amp appliance. You may not use a 30-amp breaker with 12-gauge (or smaller) wire.
And it would even be theoretically okay to use a 15-amp breaker with #14AWG wire to power that same 14-amp appliance...IF that 14-amp rating on the appliance were truly the PEAK amperage rating, and not the average amp rating.
Since this last distinction is not always obvious from the data plate, it's better to assume the figure you're given is the average amperage rating, and upgrade your supply circuit accordingly. I wouldn't recommend running a "14-amp" oven on a 15-amp circuit.
Understand: it would be perfectly safe to power an appliance rated at 20 amps with a 15-amp circuit--but it just plain wouldn't work. Every time the appliance tried to draw more than 15 amps through the wiring, the breaker would pop open and shut off the power.
The way people get themselves in trouble is in getting frustrated at that situation, and simply replacing the 15-amp breaker with a 20. Thus they are allowing TOO MUCH ELECTRICITY to flow through the 15-amp-rated wiring and overheating it. That is how electrical fires get started.Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
Thank you all for your replies. I don't think I would have got all of this from the manufacturer's technician. At least now I can ask some relevant questions when I call them, especially about the peak use amps. By the way, the oven has a "whip" that gets connected directly to the supply wires in a junction box, and I plan to use 10/3 wires.
I bought this from Sears, just being extra careful when asking about any difference.
Again, thank you.
Edited 11/5/2006 11:59 pm ET by k1c
Good luck to you. If you're not sure about anything while you're doing it, though, call in an electrician. Mistakes with this stuff can have serious consequences.
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
Sounded low to me too, but then I figured it must be a single oven.
I have double ovens I ran 6g from previos range location to new oven location.
My sparkys on the job said why did ya do that yer oven only needed 8g, I told them that friggin 1975 aluminum romex from my old range to the panel was 6g so that's what I connected to it.
I was then briefed (polite term) on the difference between aluminum & copper.
I said "OH YEAH, well it's not like I paid for the wire it came outta your scrap stash"
Had to buy him & his apprentice lunch after that comment.“It so happens that everything that is stupid is not unconstitutional.” —Supreme Court Justice Antonin Scalia