Well I've spent several months reading responses to questions on here before deciding it was time to post a question of my own. Tkrussel, you should know that your no-nonsense direction and input has been very helpful to me during the last few months as I have been rewiring a cabin I purchased last year.

Here are my questions: What size wire do I need to use for a combined oven/cook top? It is an 8,800 watt, 120/240 volt, small apartment-sized oven with 4 burners on top. I think it is about 20 inches wide. I believe I will need to run a dedicated 40 amp circuit with #8 3-wire based on previous posts. Can someone tell me if that is correct?

Most range/oven units conform to that spec. NEC code lists 40 amps for a range/oven unit.

Also by code, range tops are 30 amp and separate ovens are also 30 amps.

Nope: a #5 or larger copper wire, 4-wire circuit. Larger meaning #4, 3, 3, 1, etc.
40A breaker is correct.

KISS,

Where did you get this info from? I'll append the Code section to this note when I get home. It's the 2008 version, but this section is unchanged from prior years.

Nope: a #5 or larger copper wire, 4-wire circuit. Larger meaning #4, 3, 3, 1, etc.
40A breaker is correct.

Thanks for the prompt responses donf and KeepItSimpleStupid. I'll wait for a consensus or a definitive answer to develop regarding the wire size issue. The concern I now have is that the oven/cooktop says "three wire" on the back of it and KISS indicated that this will be a 4-wire circuit. KISS, are you counting the ground when you say "4-wire" (bare with me here as I am not an electrician and am not entirely familiar with the trade talk). Also, can I purchase the No. 5 in cable form (romex) or do I have to run conduit and pull each individual wire. Until now, I've only purchased cable in the following sizes 12-3 w/G, 12-2 w/G, 10-2, 14-2 w/G.

#5? In the past, they allowed dryers and ranges to use the same conductor for neutral and ground. I think you can run 8-3 with ground. Red and black to the hots, white to the neutral, and bare to the metal shell. Break the neutral to ground connection if it has one. Is this a built in, one piece unit?

Don't buy any wire yet.

Because of the 240/120 designation. I assumed a neutral. Ranges in the past did not use the neutral. Code, I think, dictates that 4 wire circuits should be used for new work.

So, check the connections available. You may have to remove a ground strap to utilize the safer 4-wire connection.

The terminology is 3 pole with ground.

It looks like your right #8 is OK.
The NEC code says to use 60 deg. Ratings.
From: Engineering (http://www.cerrowire.com/default.aspx?id=53)

The generic term for Romex is NM-B. Some NM-B cables are here: Dale Electric Supply Co. - Since 1947 - Wholesale and Retail Electrical Supplies (http://www.dale-electric.com/)

I think #5 wire may have meant be #6. I always pull 6's instead of #8's, you then choose 40 or 50 Amp Breaker, no repulling wires later. That would be 2 #6's for hots, a #8 for Neutral, and 10 for ground.

Minimum size circuit for a range is a 40 amp , that would use #8-3 Romex cable.

It will be called 3 wire, with a black, red, and white, but there is a fourth bare wire that intended to be the ground, and is understood, in the trade.

So, as long as your #8 cable has four wires, your fine.

I would consider using #6 and going 50A for future upgrades. I have a double oven unit. I was a very happy camper to see my existing wiring was already set up for 50A because this unit required it.

Kiss,

Good morning. Here are the cites I pulled from the 2008 NEC code. Please note that there were no highlighted areas so this cites are unchanged from at lease the prior level of code.

210.19 A (C) Ampacity and Conductors. Table 220.55, Note (4) Nametag Rating.

220.18 Max load. And finally 240.140 Grounding conductor size and connections.

Well I've spent several months reading responses to questions on here before deciding it was time to post a question of my own. Tkrussel, you should know that your no-nonsense direction and input has been very helpful to me during the last few months as I have been rewiring a cabin I purchased last year.

Here are my questions: What size wire do I need to use for a combined oven/cook top? It is an 8,800 watt, 120/240 volt, small apartment-sized oven with 4 burners on top. I think it is about 20 inches wide. I believe I will need to run a dedicated 40 amp circuit with #8 3-wire based on previous posts. Can someone tell me if that is correct?
Thanks for all your help guys. Labman, the unit is a one piece unit, oven/cooktop with 4 burners. In the interest of future upgrades, I will use the 6/3 Romex (if I can find it). Alternatively, I'll use the 8/3 Romex as initially planned. For now, I'll go with the 40 amp breaker as I'm running low on available amperage. I have two final follow-up questions: (1) With a 40 amp breaker, will I need a 2-pole or a single pole? I don't really understand those designations. (2) I was not planning on wiring it direct as I understood that to be a questionable, if not illegal, practice based on previous posts. My plan was to purchase an appropriately sized plug and outlet. I just don't know what I should look for when it comes to plugs and outlets for my unit. Can you guys give me any guidance here?

A 2 pole breaker allows 240 Volts, a single pole breaker will get you 120 volts. Sounds like this needs to be hardwired, No plug or receptacle.

Labor,

Before you jump off the bridge, do you have the landlord's permission to make the change from a range to to a range/oven combination? Remember, that you also have to remove the breakers, conductors and receptacles from the panel box and behind the walls. Plus return the equipment presently installed to the owner.

If you do not have the landlord's written and notarized authorization to pull the electrical permit, then you will not be allowed to get the permit. Because you are not the owner of the property. Also, because this is a multiple dwelling, there may be other guidelines that have to be met before a permit can be issued.

I do not believe that an electrician can or will pull the permit for you again because you are not the owner of the dwelling.

Then there's the cost of the wire. #8 and #6 conductors (3) are very expensive because of the copper conductors and you would want filament conductors for their flexibility.

As to upgrading #6/3, I would not waste the money unless you have plans to change the equipment to commercial grade down the road. The controlling factor is the NEC here. They set the guidelines for the loads. The industry manufacturers then design to the spec. not the other way around.

And finally, why spend your money upgrading to #6 for an apartment that you do not own.

Labor,

Before you jump off the bridge, do you have the landlord's permission to make the change from a range to to a range/oven combination? Remember, that you also have to remove the breakers, conductors and receptacles from the panel box and behind the walls. Plus return the equipment presently installed to the owner.

If you do not have the landlord's written and notarized authorization to pull the electrical permit, then you will not be allowed to get the permit. Because you are not the owner of the property. Also, because this is a multiple dwelling, there may be other guidelines that have to be met before a permit can be issued.

I do not believe that an electrician can or will pull the permit for you again because you are not the owner of the dwelling.

Then there's the cost of the wire. #8 and #6 conductors (3) are very expensive because of the copper conductors and you would want filament conductors for their flexibility.

As to upgrading #6/3, I would not waste the money unless you have plans to change the equipment to commercial grade down the road. The controlling factor is the NEC here. They set the guidelines for the loads. The industry manufacturers then design to the spec. not the other way around.

And finally, why spend your money upgrading to #6 for an apartment that you do not own.

Don, I am not working in an apartment. Rather, I am updating and rehabbing a hunter's cabin in the north woods of Michigan that I purchased last year. Right now, I am in the process of installing new electric, including a new apartment-sized oven/cooktop combo unit. All of the electrical will be inspected after installation of a new meter socket, an exterior main breaker and an interior sub panel.

A 2 pole breaker allows 240 Volts, a single pole breaker will get you 120 volts. Sounds like this needs to be hardwired, No plug or recepticle.

So, is it correct for me to assume that I'll need to use a 2 pole breaker? Unless I am mistaken, the back of the unit says "120/240".

I've got to double check it, but I don't believe there was a plug on it when I looked at it over the weekend. Does the absence of a plug require that I hardwire it or does that simply mean that I've got to purchase a plug and corresponding outlet?

There are many things you can get away with: aluminum wiring, #8 for ranges, and #14 for recepticles. I refuse to do any. I believe in Overkill. Compare the price difference between the 2, if too expensive, use #8. Motors and Compressors especially love larger conductors. Never seen a problem with too large a conductor, have seen problems from too small a conductor.
Donf, you answered his question, I was probably saying "What I would do"
Take Care

You can buy the wire now. Buy a matching 4 prong cord set or pigtail and an outlet that matches it plus a double pole breaker. I haven't paid too much attention, but the big box stores have a big selection of cords and outlets. Look for 4 prongs and an amp rating matching your wire. If you find the #6, you can buy all 50 amp. Otherwise, it all must be 40 amp. Connect the red and black each to a screw on the breaker. The double pole breaker has 2 clips on the back to go on each buss, and2 screws to hold wires. If it has 2 handles, they are linked. Connect white to the neutral bar and bare to the equipment ground bar. The outlet should have directions or be marked where the wires go, perhaps red and black to L1 and L2. If no other way, make sure all 4 wires connect to the same ones in the cord set. Connect the cord as I said earlier.

Check code and see if a built in requires a cord, or just a disconect.

There are many things you can get away with: aluminum wiring, #8 for ranges, and #14 for recepticles. I refuse to do any. I believe in Overkill. Compare the price difference between the 2, if too expensive, use #8. Motors and Compressors especially love larger conductors. Never seen a problem with too large a conductor, have seen problems from too small a conductor.
Donf, you answered his question, I was probably saying "What I would do"
Take Care

Thanks Strat. I too believe in overkill.

You can buy the wire now. Buy a matching 4 prong cord set or pigtail and an outlet that matches it plus a double pole breaker. I haven't paid too much attention, but the big box stores have a big selection of cords and outlets. Look for 4 prongs and an amp rating matching your wire. If you find the #6, you can buy all 50 amp. Otherwise, it all must be 40 amp. Connect the red and black each to a screw on the breaker. The double pole breaker has 2 clips on the back to go on each buss, and2 screws to hold wires. If it has 2 handles, they are linked. Connect white to the neutral bar and bare to the equipment ground bar. The outlet should have directions or be marked where the wires go, perhaps red and black to L1 and L2. If no other way, make sure all 4 wires connect to the same ones in the cord set. Connect the cord as I said earlier.

Check code and see if a built in requires a cord, or just a disconect.

Thanks for your input labman. Your suggestion is what I had in mind and its nice to get an affirmation. I will play it safe and install a plug and outlet (provided that I confirm the absence of a plug on the unit). If the wire/conductor, plug and outlet is rated for 50 amp service, I'm assuming I can still use a 40 amp 2 pole breaker.

Labor

Sorry for the confusion about the apartment. I read the unit description and leaped to an unfounded assumption. Not the first time, but I do apologize.

However, that said, NEC code says that the combined Range/Oven will operate at 240 VAC with an ampacity of 40 amps, max. It makes no distinction between an apartment or a single dwelling residence.

By code, you will need a 40 amp Dual Pole, Single Throw breaker. Using #8/3 cable you connect the Black lead to one pole and the Red lead to the other pole. Ground and Neutral will connect to their respective bus bars. One lead per hole, do not double up the leads. Make sure that you leave enough wire to reach the bus bars.

Snake your wire to the panel first, add the outlet box in the kitchen. Place the box within six inches off the floor. Purchase a four port receptacle and face plate and a four wire range/oven line cord. On the unit, disconnect the ground lead. Place Black lead on one pole, the Red on the other pole. Neutral and Ground are connected as diagrammed. At the wall, install the outlet, connecting the leads as indicated on the back of the receptacle.

Now install the faceplate. Back at the panel, turn off the panel, connect the Black and Red leads to the breaker and install the breaker. Then cut the White and Ground leads to fit the length needed to Range Breaker on.

The more I think about it, the less sense a cord makes. If it is built in, how are you going to unplug it before working on it?

Ouch!

You have to use a 4 prong cord to connect to the receptacle. How about just because that's what NEC says you will do!

Also, Range/Oven units are designed with an open area under the unit to allow the extra cord a place to hide. You need the cord length so that the unit can be pulled out from the surrounding cabinets, if there are any, to allow a tech to get behind the unit for any live work he needs to do.

Please, a little common sense!

Where does Code say it has to be plugged in?

I was just at Lowe's and I found 3 and 4 conductor range cords pre-made with ring terminals.

The plug/cord depends on whether you can "convert" or use 4 wires. If three are used, then use the appropriate receptacle and cap off the white in the receptacle box.

Available amperage is not a function of the sum of the breaker values. The panel can accept a certain number of poles or places you can attach wires to and that is specified on the nameplate.

There are two types of breakers. One is designed to operate a 240 V load and the other is designed to operate two 120 V loads. The former has a bar between the breakers. The latter does not. It has 2 independent breakers in one unit.

Strat,

Under the index, Ranges first subject sends you to 422.16. Exception 2.

OOps, I was thinking cooktop, Another post. Ignore my statement about "where does code say..." Thanks, Take Care
I still use 2 6"s ,1 #8, and a 10. I never? Have to upgrade.

Don, please re-read Section 422.16 of the 2008 NEC. It is for flexible cords, and does not address whether a disconnect is required or not.

Which exception? I see no Exception #2. An exception will be related to a certain sub section.

I see no ranges listed in 422.16, other than 422.16 (3), which is for Wall mounted Ovens and Counter mounted cooktops, and how flexible cords shall be permitted, if used, but not required.

And no one should ever hesitate to ask "where in the code does it say"...