help with new oven wiring

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  #1  
Old 09-04-06, 06:30 PM
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Question help with new oven wiring

The new oven details:
KitchenAid Wall Oven: requires 30 amp circuit.
Electrical connection instructions read: use 8 gauge solid copper wire. Electrically ground range.

My home has: (in conduit) red, black, white 10 gauge solid copper.

4 wires from new oven, in metal cable are: red, black, white, bare copper.

Do I really have to replace #10 & pull new solid #8? (I thought 30 amp was #10.)
Can I use threaded #8 instead of solid?
What do I do with the bare copper wire?

Install instructions read:
If local codes PERMIT connecting cabinet-grounding conductor to the nuetral white wire in junction box: connect bare factory-crimped bare and white oven cable wires in juncton box. (the wires were not factory crimped though)

I local codes DO NOT PERMIT..(same as above): connect white to white, connect bare to grounded wire in junction box.

There is no grounded wire in junction box.
The old oven wiring was #12, w/crimped bare and white connected to white #10. which may or may not have been installed correctly

HELP!
 
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  #2  
Old 09-04-06, 06:51 PM
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How the previous unit was hooked up is of little value. This new unit needs to be connected properly.

You are correct in that a 30 amp circuit typically means 10 gage wire.

However, if the instructions of an appliance or device specify something, then generally you must follow what is specified.

It appears that to comply with the installation instructions, you must pull new conductors, which must be solid copper number 8. You would need to pull four conductors, allowing one for the ground, which could be bare or could be green insulated.

The good news is that this is conduit, meaning that you can (with assistance and with some work) pull the new wire.

I am interested to see what others have to say about these installation instructions. Perhaps there is a way out for you.
 
  #3  
Old 09-04-06, 07:14 PM
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I googled the installation instructions. They can be found here:

http://www.kitchenaid.com/assets/pdfs/literature/Installation%20Instructions%20-%204452615.pdf

They appear to be generic instructions writtin to be sent to several counties. It specificly says that you should get an electrician to decide the circuit size and wire size for your local area.

What is the modle number? It shows different model numbers have different requirements.

If it is the 30 amp model as you say, I would go with the 30 amp breaker and number 10 wire. Use the four conductors that you have keeping the ground and neutrals seperate. Be sure and pigtail a ground to that junction box where you make the connections.

Edit to add: Can you post also the name plate data from the Microwave itself? The directions say that you should be able to find that info on the oven frame, or oven door.
 
  #4  
Old 09-04-06, 07:59 PM
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Model # KEBC107KSS05
3 wire 120/208-240 volt 80 HZ AC only
Kilowats 4.8 @ 120/240 volts

Installation instructions also say: Models rated from 7.3 to 9.6kW at 240 require a separate 40 amp circuit. Models rates at 7.2 kW and below at 240 volts require a seperate 30-amp circuit.

Your wire connection advise sounds logical to me. What about the #8 solid copper wire, as noted in instructions though? can I use stranded #8 instead, if I have to pull new wire?
 

Last edited by bbqbyrds; 09-04-06 at 08:18 PM.
  #5  
Old 09-05-06, 04:59 AM
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Smile

You are allowed to utilize a EXISTING 3 wire feed (2 hots and a ground) to your oven.
The branch circuit has to be large enough to supply the load.
4.8 Kilowatts = 20.9 Amps at 230V supply
#10 copper is good for 30 Amps
Follow the instructions for hooking the neutral and ground together on the oven.
 

Last edited by DIYaddict; 09-05-06 at 07:03 AM. Reason: removed quote as it's unnecessary to quote the entire post that's directly above yours
  #6  
Old 09-05-06, 09:57 AM
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Originally Posted by bbqbyrds
Your wire connection advise sounds logical to me. What about the #8 solid copper wire, as noted in instructions though? can I use stranded #8 instead, if I have to pull new wire?
Hillbilly covered the ground/neutral issue.

As for the solid/stranded issue. IMHO stranded is better wire. It is also usually more expensive.

I don't think you have to worry though, as you can re-use the wire you have.

If you decide to pull new wire, then the clause that hillbilly mentioined will no longer apply. (you will not be grandfathered in) You will need to pull four wires to replace the three you have.
 
  #7  
Old 09-05-06, 01:40 PM
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It sounds like you are all in agreement that I can just hook up to the three existing #10 wires.
What about that 4th wire, the bare copper though? Hillbilly says fasten bare and white together. I spoke to an install guy at the local appliance store who felt that unless the bare wire and the white were crimped at the factory, that I should attach the bare copper to the junction box. That option seems more in line with the instructions I quoted in my original post. Any further thoughts on that issue?

One last issue I thought of is the length of the run from panel to oven. The original oven was about 40' (50' max) from panel. I now have a junction box at what was the oven, and have extended the wires in a new run of conduit to the new oven location, about another 15-20'. Is this an issue at all?
 
  #8  
Old 09-05-06, 01:49 PM
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Yes, your extension is an issue. You should have mentioned it originally. You cannot legally extend a three wire circuit for this purpose.

If the existing conduit supplied an approved ground and you extended with conduit that continues the ground then you have a ground by using the metal box.

However, if the conduit is PVC or otherwise does not supply an approved ground then you MUST run a new wire in the existing conduit for the ground.

Further, the junction box you added MUST be permanently accessible. If for any reason it is not, then you need to make it so.
 
  #9  
Old 09-05-06, 03:14 PM
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All the conduit is metal, and all the junction boxes are accessible. So I can't extend a three wire circuit? There is nothing else in the junction boxes except this circuit.
 
  #10  
Old 09-05-06, 03:35 PM
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The issue here is that a three way circuit is no longer correct for this installation. The installation requires a four wire circuit. Your three wire circuit is grandfathered as long as you do not have to modify it. Extending it as a three wire circuit is not allowed.

In order to use this circuit with only three wires you need the proper type of conduit and the conduit MUST make a proper connection at both ends. This is sometimes difficult and not necessarily reliable.

Since it does not appear the the three wire circuit used the conduit as a ground, and because of the difficulty verifying the existing conduit, I recommend that you install a ground wire all the way back to the main panel. If you do this you will have a proper four wire circuit. Done.
 
  #11  
Old 09-05-06, 04:37 PM
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OK, so if I pull four new wires, assuming I can't extend the existing 3 wire circuit legally, and I make the red, black, and white #8, even if it is overkill, then what about the ground (green)? what # does it need to be? where does it hook at the panel? Or, do I only need to pull 4 wires from the new junction box to the old junction box, since three wires was alright from there before?
 
  #12  
Old 09-05-06, 04:58 PM
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Pull three wires from the old junction box to the new junction box. Make them #10 to match the existing wires, and match the colors.

Pull one wire from the main panel to the new junction box. Make it #10 and either green insulated or bare.
 
  #13  
Old 09-05-06, 05:56 PM
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Originally Posted by racraft
Pull three wires from the old junction box to the new junction box. Make them #10 to match the existing wires, and match the colors.

Pull one wire from the main panel to the new junction box. Make it #10 and either green insulated or bare.

Now your DONE. And it's All good.
Pulling tip #1) Buy #10 green and another color, use the existing wire (of the same color) as a pull wire in the old conduit.
(pull in stranded #10 much easier in an existing run.)
 
  #14  
Old 09-06-06, 08:28 AM
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All my existing house wiring is grounded using the conduit. Where am I fastening the new green wire in the panel?
 
  #15  
Old 09-06-06, 08:32 AM
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Assuming that this is the main panel in your house then the green ground wires gets connected to the ground/neutral buss, which should be where the external ground is connected. The external ground is where the water pipes in the house and the external ground rod connect. If this is the main panel then a three wire feed will come in from the meter.

If this is not the main panel in the house then you either need to find a ground buss or install one. If this is not the main panel in the house then a four wire feed will come in from the meter box, where there will be a main disconnect.
 
  #16  
Old 09-06-06, 09:44 AM
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Art 250.118 Types of Equiptment GroundingConductors (EGC ) -----

"The EGC ENCLOSING the circuit-conductors (Black/Red/White wires) shall be--- (4), Electrical Metallic Tubing ---- "

If the assembly of the EMT raceway forms a solid and continual metallic path between the panel and the outlet-box where the appliance connects, then the EMT is an approved EGC.

You could improve the Ground-path by threading
"Bonding bushings" on the threads of the EMT connectors at both ends, and connecting copper "jumpers" to the lugs on the Bonding bushings. At the Service panel, the jumper connects to the Neutral terminal strip; at the outlet box, it connects to a lug fastened to the surface of the box.
 
  #17  
Old 09-06-06, 12:10 PM
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Originally Posted by PATTBAA
Art 250.118 Types of Equiptment GroundingConductors (EGC ) -----

At the Service panel, the jumper connects to the Neutral terminal strip; at the outlet box, it connects to a lug fastened to the surface of the box.
Sorry for continuing to beat a dead horse here. When examining the panel there are three wires in from meter, 1 common and 2 hot. There is one bare copper wire in BX attached to the common bar in the panel, going up to who knows where. The common bar is attached (grounded?) to the panel itself by a small metal strip attached to a green screw. I see no obvious other grounding of the panel to the ground, water pipe, etc.

PATTBAA, Are you saying that I don't need the green 4th wire?
 
  #18  
Old 09-06-06, 12:15 PM
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The "common bar" (neutral buss) is BONDED to the panel.

The copper wire coming in from "who knows where" is your ground wire.

Connect the green wire you are adding to the neutral buss.

This green wire is not mandatory. If the conduit is intact and you can verify it's function, it can function as the ground. I told you this from the beginning.

However, verifying the conduit as a proper ground is not a trivial matter, and the previous ovendid not use it as a ground. (I don't know why the previous oven did not use it as a ground.) For this reason I strongly recommend that you pull the extra wire and use it as the ground.
 
  #19  
Old 09-06-06, 05:28 PM
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Thumbs up

thank you to all responders. I think I'm good to go on this.
 
  #20  
Old 09-06-06, 08:56 PM
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Originally Posted by racraft
Pull three wires from the old junction box to the new junction box. Make them #10 to match the existing wires, and match the colors.

Pull one wire from the main panel to the new junction box. Make it #10 and either green insulated or bare.
I have this exact same issue. I am purchasing a new stove that needs a 4-wire outlet. The old location of the stove is approx. 10 feet away from the new location. I understand that I need to have a ground all the way back to the panel. Is it acceptable to wire just a ground all the way back to the panel from the new location, and just 3-wire from the old location to the new location?

The old location would be spliced in a junction box, 100% acceptable (dropped ceiling in basement). With the high cost of wire, anything I can do to save some $$$ is a big help.
 
  #21  
Old 09-07-06, 05:56 AM
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[QUOTE=bbqbyrds]It sounds like you are all in agreement that I can just hook up to the three existing #10 wires.
What about that 4th wire, the bare copper though? Hillbilly says fasten bare and white together.

I want to clarify because I think that you misunderstood me. I used the word "together" in my original post, and that is probably not the correct word. I was trying to tell you to use the instructions that came with the stove when you hook up the neutral "and" ground.
The neutral and ground "NEVER" get tied together downstream of the main breaker panel. They are bonded together in the Main Panel along with the Grounded service conductor and the grounding electrode conductor. That is the only place that they should ever touch each other.
steve.
 
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