What do I do with the White Wire

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  #1  
Old 04-25-04, 01:57 PM
Rondo
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What do I do with the White Wire

I am installing an new 220v oven (Jenn Air) that is wired to the new 4 wire standard (2 hots, ground & a white neutral) in a home that only has the 2 hot leads and a bare ground (schielded cable) that is grounded to the grounding teriminal in the service - grounded neutral.

I know the red and black from the oven goes to the hot leads and the bare ground from the oven should go to the bare wire from the feed line but what do I do with the white neutral from the oven - Am I suppose to terminate it or connect to the grounded neutral???

Dave
 

Last edited by Rondo; 04-25-04 at 03:08 PM.
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  #2  
Old 04-25-04, 03:46 PM
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I hate to break this to you but you must run a new line from the panel.Since the 1996 NEC the grouning conductor is not alowed to be used as a neutral.Therefore you need to use a 3 wire cable {2 hots, 1 neutral,1 ground} with an ampacity suitable for the range.
 
  #3  
Old 04-25-04, 04:16 PM
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For electric ranges and clothes dryers, it _used_ to be permitted to ground the frame of the appliance using the neutral conductor. This was not as safe as having a separate ground and neutral conductor, but it was considered acceptable. As ampz noted, this was changed with the 1996 edition of the code.

Under some circumstances, you can continue to use a three wire branch circuit for a new range. This is called grandfathering, the practice of leaving old apparatus in place if it was installed correctly under the original code rules. A 'grandfathered' circuit is _not as safe_ as a circuit installed to current rules, however safety is always balanced against cost, and re-wiring is almost always more expensive than new wiring, so the safety standards for old wiring are slightly lower.

If you can install a new four wire circuit, IMHO you should do so.

1) If your three wire circuit was installed after the 1996 code took effect, then it was not code at the time of the install, and thus not permitted to be grandfathered. Clearly the difference between a circuit permitted to be grandfathered and one not permitted to be grandfathered is purely legal, but if someone didn't know enough to install a circuit to code, then do you really want to trust their work?

2) The installation manual which came with your range should describe how to connect it to a three wire circuit. If the installation manual does not show how to make a proper connection to a three wire circuit, then it may be that the range _must_ be on a four wire circuit. In this case you will need to change to the 4 conductor cable. If the manual does not show a correct connection to three conductor cable, then contact the manufacturer.

3) The grounded (neutral) conductor must be 10ga copper or larger or 8ga aluminium or larger. If the neutral is too small, then you will need to replace the cable.

4) The grounded (neutral) conductor must either be insulated, or if it is not insulated it must be part of 'Type SE service entrance' cable. If you have 'Romex' type cable with a bare ground, then you will need to replace the cable.

If you meet all of the above requirements, then the instructions from the manufacturer will explain how to connect the ground and neutral correctly for your particular range.

-Jon
 
  #4  
Old 04-25-04, 04:21 PM
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No, you do not have to run new wire. Code requires you to upgrade to 3-wire plus ground only if you are replacing or wiring the circuit. Since you are merely replacing the appliance, no upgrade is required.

All ranges come with two sets of instructions, one for 3-wire connections and one for 4-wire connections. Study the installation instructions more carefully and find the alternative set of instructions. Follow them exactly. It will require the connection of a bonding strap on your range.
 
  #5  
Old 04-26-04, 08:38 PM
Rondo
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Jenn Air directions confusing

The manual reads:

The neutral of this unit is grounded to the frame through the green or solid grounding wire. (The green and the white wires are twisted together at the termination of the conduit.) If used on new branch-circut installations (1996 NEC), mobile home, recreational vehicles, or in an area where local codes prohibit grounding through the neutral conductor, untwist or disconnect the green wire and connect the green wire to ground in accordance with local code. Connect the white neutral to the service neutral. Connect all wires with approved connectors.........


The part that confused me was "(The green and the white wires are twisted together at the termination of the conduit.)" Which I took to mean in the juction box.

BUT then it went on to say "If used on new branch-circut installations (1996 NEC), mobile home, recreational vehicles, or in an area where local codes prohibit grounding through the neutral conductor," >>>Here is the confusing part >>>" untwist or disconnect the green wire and connect the green wire to ground in accordance with local code."

This seems to imply the the wires were already twisted together but they aren't. Do the directions assume I read the "(The green and the white wires are twisted together at the termination of the conduit.)" and twisted them together?? And then go on to say that I should untwist???


The oven is installed so I check it with a meter. There are no diagrams but the grounding wire is grounded to the frame of the oven and the white wire isn't.


All others appliances I have ever installed in older homes (all my own) I have connected the green or solid grounding wire to white neutral in the junction box when code allowed.


Thanks in advance for all your help.

Dave
 
  #6  
Old 04-27-04, 05:18 AM
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The directions _are_ confusing. It is not clear if the wires were already _supposed_ to be joined, or if you are supposed to join them at the time of installation, or if they are joined elsewhere in the appliance. However since you have a three wire feeder to your oven, the second part of the instructions:
BUT then it went on to say "If used on new branch-circut installations (1996 NEC), mobile home, recreational vehicles, or in an area where local codes prohibit grounding through the neutral conductor," >>>Here is the confusing part >>>" untwist or disconnect the green wire and connect the green wire to ground in accordance with local code."
do not apply to you.

The 'common sense' reading is that in the junction box you should join the white wire from the range, the green wire from the range, and your neutral feed. Because the instructions are unclear, I would suggest checking with the manufacturer.

Could you tell us what sort of cable is used to feed the range?

-Jon
 
  #7  
Old 04-27-04, 06:24 AM
Rondo
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It is has two hot leads and a "neutral ground" there is no separate neutral. The house was built in 1975.

Dave
 
  #8  
Old 04-27-04, 06:29 AM
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Is the neutral/ground a separate insulated conductor, or is it bare?

If bare, is the neutral/ground a bunch of wires that surround the hot leads, or is it a single conductor?

Are the conductors copper or aluminium?

Can you see the printing on the cable anywhere? What does it say?

-Jon
 
  #9  
Old 04-27-04, 09:33 AM
Rondo
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I am at work now I'll check the cable label when I get home.

The neutral/ground is a bunch of wires that surround the hot leads.

The conductors are aluminium.

Dave
 
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