Cooktop and Electric Installation

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Old 03-15-13, 09:14 AM
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Cooktop and Electric Installation

Hello,

I bought a cooktop to build me a nice kitchen.

Shop Whirlpool 30-in Smooth Surface Electric Cooktop (Black) at Lowes.com

It does not say how much AMP it has.
My fuse shows 53 AMP.
I have three wires (I think AWG 6) coming out of the wall.
Red, WHite and Black.

Name:  Wires.jpg
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Out of the cooktop are only coming a red, a black and a copper wire. (Wires look like AWG 14)

How do hook it up to the electrical box?

Thank you
 
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Old 03-16-13, 12:43 AM
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That picture is the insides of a range receptacle. You could install a cord on the cooktop to match.

If the cooktop comes with its own power cable then you will need to remove that existing receptacle from the wire and install it into a 4" square junction box. Now connect the wire that comes from the cooktop into the same junction box.
Red to red
black to black
white to bare.

See page 7 of the installation instructions for that unit. If you don't have them yet, see page 7 in the link below.
http://pdf.lowes.com/installationgui...25_install.pdf
 
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Old 03-16-13, 07:42 AM
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My fuse shows 53 AMP.
No such thing as a 53 amp fuse in residential service and I'd be surprised if you had fuses at all. You need a 40 amp 2 pole breaker or 40 amp fuses for the cooktop.
 
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Old 03-16-13, 08:03 AM
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No such thing as a 53 amp fuse in residential service and I'd be surprised if you had fuses at all. Your picture shows a 3-wire branch circuit. Might be time to upgrade to a safer four wire service.
The installation instructions do not give the maximum overcurrent protection anywhere that I could see. Working backward from the requirement for #8 AWG wire (box at top of p. 6 in the instructions) gives 40A.

The wire coming out of the cooktop will not be #14 AWG unless the fuel is gas, not electricity.

You should replace the cable from the wall to the panel with a 4-wire #8 AWG cable as Ray suggested and protect that with a new 40A 240V breaker, replacing the breaker that is protecting the heavier 3-wire cable now. You should then install a J-box under the counter and splice the whip for the cooktop to the wires from the panel in that box as the instructions show.

There should be a nameplate on the cooktop that gives the specific information on the load and required overcurrent protection.
 
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Old 03-16-13, 09:05 AM
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If you look at the link I left which was the actual model in question here.......it states a 40 amp two pole breaker.
 
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Old 03-16-13, 09:11 AM
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Yes, my 40 amp was based on the linked PDF.
 
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Old 03-17-13, 08:00 AM
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Hello all,

thank you so much for trying to help, but I am totally confused now.
I read here that it is possible to hook up both, the cooktop and the oven to the same box.

wiring oven/cooktop | Fine Homebuilding | Breaktime

@ ray2047
Sorry, but I meant braker. In Europe is fuse, here braker.

Here are picture what's under the cooktop, the wires and the fuses box, ahm for ray2047, braker box.



(Larger image http://imageshack.us/a/img138/3920/bild024cy.jpg)




 
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Old 03-17-13, 08:08 AM
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A 3-wire or 4-wire, single phase, 120/240 volt, 60-Hz., AC only electrical supply is required on a separate, 40-amp circuit fused on both sides of the line
That is from the installation manual from the cooktop you are looking at.
So if the circuit needed to be protected at 40 amps you could not tie a second device in.

Even if you were using a 50 amp breaker....both units combined require 60 amps. That would also be an issue.

You mentioned on the other site adding a sub panel and increasing the circuit size. It would probably be easier to just add the needed new 20 amp circuit.
 
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Old 03-17-13, 12:01 PM
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Can't the cooktop just hooked up to the oven direkt?
And what if I would replace the 50amp braker with a 60 amp one?
In Europe you can hook up the cooktop to the oven and using only one outlet box.

 
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Old 03-17-13, 07:24 PM
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If you look at the link I left which was the actual model in question here.......it states a 40 amp two pole breaker.
The link I included actually shows the same thing. I just missed it. It's at the bottom right of p. 4, under Before You Make the Electrical Connection:
To properly install your cooktop, you must determine the type of
electrical connection you will be using and follow the instructions
provided for it here.
■ A 3-wire or 4-wire, single phase, 120/240 volt, 60-Hz., AC
only electrical supply is required on a separate, 40-amp
circuit fused on both sides of the line
.
I think the two links show the same pdf.

[Note to self: Read full threads!]
 
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Old 03-17-13, 07:46 PM
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Can't the cooktop just hooked up to the oven direkt?
Speaking of reading full threads, this is from the final post in the thread you linked to:
The only real answer is in the installation instructions... You need to be sure that if there is an internal fault that the internal wiring will hold until the breaker trips.
This is covered in Section 110.3 of the NEC, among other applicable sections.
 
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Old 03-18-13, 02:12 PM
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You should replace the cable from the wall to the panel with a 4-wire #8 AWG cable as Ray suggested and protect that with a new 40A 240V breaker, replacing the breaker that is protecting the heavier 3-wire cable now. You should then install a J-box under the counter and splice the whip for the cooktop to the wires from the panel in that box as the instructions show.

There should be a nameplate on the cooktop that gives the specific information on the load and required overcurrent protection.
How do I replace a 3-wire cable with a 4-wire cable?
And couldn't I just use the current power and add the new ones later for the oven?
 
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Old 03-18-13, 02:46 PM
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I am confused. Are yo talking about the cable on the cooktop or the one on the wall which I need to replace?
 
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Old 03-18-13, 02:49 PM
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As I said in my first post the cable in the cooktop isn't relevant to the discussion except for the number of wires. The only thing relevant is the cable from the wall it is connected to and that is what this discussion is about.

This is the new cable you need to run from the breaker box to the junction box where you will connect the whip (group of wires) on the oven.



And this is a 4x4 junction box that would be used for the connection. You would put a blank cover plate on it.



Assuming the whip on the oven is metallic yo will use a right angle connector at the Jbox.

and an NM connector for the 8-3 Romex.
 

Last edited by ray2047; 03-18-13 at 03:17 PM.
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Old 03-19-13, 08:11 AM
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Thank you, but my questions WAS if I can use and hook up the cooktop to the current wires and how.
I know now that I have to add a new braker, run new wires for the oven itself and to hook up both separately.

Sorry for my stupidity.
 
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Old 03-19-13, 08:55 AM
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Yes, you can use the current wires for the cook top. Does it have a whip? Is the whip 2 wires plus a ground or 3 wires plus a ground? Your current cable has no ground. It is grandfathered but by current code a white that small can't be repurposed as a ground so if the whip on the cooktop has only two hots and a ground there is really nowhere to hook the ground. If the whip is four wire ground and neutral can be connected together to the white wire. Yes, confusing and it all depends on what the inspector says. I'd run new cable just to avoid the confusion or run just a new ground wire to it. No easier but cheaper and would be code compliant.
 
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Old 03-19-13, 09:21 AM
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Damn. I thought I could avoid that to run new wires for the cooktop.
Thank you though
 
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Old 03-19-13, 09:25 AM
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You can if the whip on the cooktop is four wires. It is only questionable if it has just two hots and a ground because the ground alone should not be hooked to a white. Check with your inspector.

You could run #4 on a 70 amp breaker to a small subpanel if you have a suitable place to put it then branch out to each off separate breakers. Code also permits combining the two on a 70 amp circuit as you originally asked about but that would probably offer no protection for the internal wiring of either one. (Code is about protecting the wire to the outlet not after the outlet.)
 
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Old 03-19-13, 09:36 AM
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It has two hots and a ground only.

According to this circuit dwg it has only the possibility to mount two wires on.
Would be easier just to replace the two wire + ground with a 3 wire + ground.
(right click to get a larger image)

 
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Old 03-19-13, 01:52 PM
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I may be missing something but I don't see the controls and display in that circuit drawing.

Would be easier just to replace the two wire + ground with a 3 wire + ground.
Less confusing too.
 
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Old 03-19-13, 01:58 PM
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Oh man, please don't write in riddle.

Can I just replace the 2-connector cable on the cooktop with a 3-connector one?
 
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Old 03-19-13, 03:08 PM
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Can I just replace the 2-connector cable on the cooktop with a 3-connector one?
No. You can only change the wiring from the wall.
 
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Old 03-20-13, 09:25 AM
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Oh man, please don't write in riddle.
What didn't you understand? It can probably be said a different way.
 
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Old 03-23-13, 09:33 AM
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I have an update.

If you have an older home with three wires, red, white and black, and you have a electric range or cooktop with a red, black and ground wire, it is allowed to connect the ground to the neutral (white).
I did that. Works great.

Mod Note: There are safety issues with the statement above and it may not be code compliant. See next post.
 

Last edited by ray2047; 03-23-13 at 09:56 AM.
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Old 03-23-13, 09:50 AM
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and you have a electric range or cooktop with a red, black and ground wire, it is allowed to connect the ground to the neutral (white).
Generally a white #6 or smaller can not be used as a ground. So it may work but is not code compliant and you are providing a path for everything with a neutral though the metal of the cooktop which could be dangerous. What gets confusing here is code does permit ground and neutral of a four wire appliance to be connected to a neutral but you do not have a four wire appliance.

Time and time again we have told you how it needs to be connected. If you wish to ignore that advice and do it in an unsafe manner just because it works that is your choice.
 
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Old 03-23-13, 11:51 AM
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It just doesn't make sense for me.
Here is a source that confirmed it too.

Wiring a Range Power Cord
 
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Old 03-23-13, 01:25 PM
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This is from that link:

"The following steps apply ONLY if the range specifically states that it can be wired for either 3-Wire OR 4-Wire Connections. Some new ranges may require a Separate Insulated Neutral Wire AND a Separate Ground Wire for a 4-Wire Connection Only.
Be sure to consult your range installation manual specifications for the configuration that is allowed."

Does the manufacturer allow this type of connection?
 
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Old 03-23-13, 02:17 PM
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Old 03-23-13, 02:36 PM
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If you feel safe doing it that way then that is your choice.
 
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