240v range receptacle question

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  #1  
Old 02-09-15, 12:47 PM
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240v range receptacle question

We just moved into a new house, came with a brand new LG electric range. We are used to gas so we ordered new GE dual fuel and planned to sell the electric LG.

I knew that the GE dual fuel needed the receptacle at floor level same as current but on right side.

I came to move it last night and discovered that when they installed the LG they installed the new lower box into the enclosure for the furnace return that occupies the bottom 7" along the available width. They drilled through the horizontal upper stud and ran 5" of conduit down into the new box.

You can see the grill for the furnace return through the hole in the drywall.

I had no idea the furnace return box occupied the whole wall cavity, assumed when I saw the relod box that they had done it correctly. My reading of NEC is that you can run conduit into HVAC venting but only for devices that have something to do with the HVAC. Also I'm struggling to see how gas line installer will cope as GE manual says gas needs to be left side at floor level and the return box actually wraps under the kitchen floor 2". I'll wait and see what he says.

We may exchange GE to a Bosch which needs electric box 12" off ground on the right hand side which is above the return box at same level as original 220 box. I may run new 8ga wire to panel which is directly underneath using old as pull, rather than do another extension with lugs. If I do this should I run 4 wire? Its not a subpanel so ground/neutral are bonded in the panel so I'm not sure if there is a practical advantage to 4 over current 3?

There is a vertical stud on the right of the two current boxes and another vertical stud on the right of the small pilot hole I drilled and the the horizontal stud 7" up the seperates the return box from rest of wall cavity.
 
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  #2  
Old 02-09-15, 12:55 PM
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Four wire is required by code. Even the existing three-wire cannot be moved by code because it is grandfathered as-is, but new location isn't.

Since you're only talking a few feet of new cable, I'd run it new and leave a loop of cable to a surface mount box behind the range. That would allow you to relocate the box whereever it fits for the range you end up getting. You can route the new cable through the back of the adjacent cabinet if you can't get access directly beneath because of the HVAC duct. New cable should be 8/3g NM-B
 
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Old 02-09-15, 01:24 PM
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I expect well be governed by the gas, if we have to swap to the Bosch its install instructions say that flush mount receptacle is required, so that the range goes fully against wall. Lots of reviews of the GE say it didn't go all way back against wall, presumably because either gas or electric wasn't placed correctly
 
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Old 02-09-15, 02:21 PM
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Gas and electric connections are always an issue as the appliance manufacturers don't follow any type of standardization in hookup locations on the appliances.
 
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Old 02-09-15, 03:03 PM
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So the gas guys came, only option is to run flex gas line inside the return (which is the joist bays just covered with sheet metal rather than actual ducting). Supposedly ok to run inside supply duct but they were unsure on inside a return. They called someone in a different jurisdiction who said that was allowed but I suggested they get answer from this city since they will be the ones doing inspection. So they left and may return end of week.

City called me back and chief inspector confirmed I can't run wire inside ducting unless device is for HVAC (smoke detector etc) so I'm assuming that prohibits going through return box also.

Install instructions are below, pic on last page shows surface mount box so I think I can run new wire horizontally behind wall through current upper box location (above the horizontal stud that is the upper part of return box), abandon the box and come through wall 3" from right side and then run wire down outside to surface mounted junction box just above floor per location in instructions. Can't come through side of cabinet as back left edge of stove literally touches rear wall. This is the style that has controls on front so it goes flush with back wall (ideally)

Gas guys said Bosch required gas location is worse for them and it requires flush mount electric box which I dont see how I can access so I guess we're keeping GE.

http://products.geappliances.com/Mar...e=31-10982.pdf
 
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Old 02-09-15, 03:18 PM
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I don't believe gas can be run thru any ductwork or HVAC air carrying chamber anywhere in the system.... supply or return.
 
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Old 02-09-15, 03:25 PM
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They assured me supply was done all the time. Agree it sounds like something that is a BAD idea.
 
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Old 02-09-15, 03:33 PM
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I suggest you go to a store that will allow you to look at back of range before purchasing.
I've been through this many, many times. I remodel kitchens.
The manufacturer's call outs are not always the only option. Sometimes they are, but these appliance engineers are not real high on my list of people to trust.

Once you can see back of appliance, it will take careful measurements and planning.
 
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Old 02-09-15, 04:52 PM
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Too late we already own stove plus gas is going to be issue for any as the return is two stud bays wide. City said they can run through duct (I.e in one side terminate out other) but cannot run down length, so we need HVAC guy to reduce width of return if possible, box it so it takes up 1-3/4 stud bays for example, apptmt set for tomorrow
 
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Old 02-12-15, 03:12 PM
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New cable should be 8/3g NM-B
The GE stove we're using calls for 40A minimum branch circuit. Current wiring is THHN 6ga in conduit. I know some stoves require 50A. 50A would I believe require 6/3 NM-B. Since I'm going to be buying new cable is there any reason to not run 6/3 to the panel?

The breaker is only 40 at present, sufficient for the GE. I also don't think the range comes with a cord/whip so I'll have to get one, again 40A is sufficient. I believe NEMA 14-50. The manual says to use a 40A whip and that 50A is not recommended (due to clearance into the range).
 
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Old 02-12-15, 03:30 PM
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I wouldn't recommend running anything smaller than 6/3 to a range. Connecting it to a 40A breaker is fine. I don't think a 40A receptacle and cord is physically much smaller than a 50A set.
 
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Old 02-12-15, 03:48 PM
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I wouldn't recommend running anything smaller than 6/3 to a range. Connecting it to a 40A breaker is fine. I don't think a 40A receptacle and cord is physically much smaller than a 50A set.
Yeah, I assumed 6ga but ibpooks who's a forum topic moderator earlier said "8/3g NM-B"

The manual for the GE range says:

"A range cord rated at 40 amps with 125/250 minimum volt range is required. A 50 amp range
cord is not recommended but if used, it should be marked for use with nominal 13⁄8” diameter
connection openings. Care should be taken to center the cable and strain relief within the knockout hole to keep the edge from damaging the cable"

I figure a 4' 40A whip will be cheaper than a 50A anyhow.

I'll probably as I said earlier surface mount the box and run the wire out through a hole in the drywall and then down to the box.

Not sure if this:
http://www.leviton.com/OA_HTML/Produ...&section=42418

or a standard 4" metal box and this:

http://www.leviton.com/OA_HTML/Produ...minisite=10251

is the better option.

If I go with a 4" metal box I don't believe there is any requirement to ground it (unlike a junction box), it'll be grounded via (hopefully) a solid connection to the receptacle.
 
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Old 02-12-15, 03:51 PM
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Your unit requires 8/3. You can always run larger wire. It can never hurt.

The only issue that running a larger wire can cause is that it may be harder to get to it to fit in the 40a receptacle.
 
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Old 02-12-15, 04:06 PM
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Do they make a 40A receptacle? All the 4' 40A whip cords have a 14-50p on the end. 14-50r is rated 50A. There is a 14-30r. Anyhow, we're in the weeds. Thanks for the help. I'll run 6-3, it's 30c more a foot and I only need 5' or so.
 
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Old 02-12-15, 04:38 PM
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Can I run the 6/3 NM-B inside the existing conduit? I know that's allowed for 12/x and 14/x (single cable only).

Or am I going to have to remove the existing conduit (upper left in image below, other end of conduit is attached to the junction box shown in first post)?

Also, can someone point me to the section of the NEC that deals with what protection is necessary for cables leaving the panel. On the panel at our old house I always used a short section of EMT or flex conduit (with a threaded clamp and plastic protector on the end) whenever wires existed the panel but that was in an unfinished space.

This new panel is in a "finished" space (kind of, backs upto unfinished space). I noticed they are running several wires through one knockout with just a plastic clamp.

If I have to remove the existing flex conduit I'm not sure if I can use a similar plastic clamp or if I need to retain a short section of the flex conduit where I exit the panel.
 
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Old 02-12-15, 06:11 PM
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Can I run the 6/3 NM-B inside the existing conduit?
Best practice to run individual conductors not cable in conduit.
 
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Old 02-12-15, 06:18 PM
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There is no 40 amp cord or receptacle. A 50 amp configuration is used.
 
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Old 02-12-15, 06:29 PM
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Originally Posted by pcboss
There is no 40 amp cord or receptacle. A 50 amp configuration is used.
Really? This is rated 40A but has a 14-50p at the end.

PETRA 90-2060 4-Wire Range Cord, 40A (4ft)

Originally Posted by ray2047
Best practice to run individual conductors not cable in conduit.
I realize this. If you read the earlier discussion the box needs to be mounted at floor level, so I was going to use xx/3 NM-B, run it out through the drywall above the return box and then down the wall to a surface mounted box at floor level.

I'll just remove the conduit and run NM-B. Open question, do I need a short length of flex conduit where the wire leaves the panel, or can I just use a plastic knockout clamp as they have done for the 12/2 and 14/2 (see picture of panel below).
 
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Old 02-13-15, 08:29 AM
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Yes the NEMA configuration for 40A and 50A circuits use the same plug and receptacle -- the 14-50.

Go ahead and keep your #6 in the conduit if you can -- it's better than either 8-3 or 6-3. You can always use a larger size wire than required.

The NM cable does not need to be sleeved in flex. It can utilize a normal cable clamp at box KOs, stapled to studs, etc.
 
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Old 02-27-15, 01:45 PM
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I've been fixing up our old house, finally getting back to this.

So we had the gas installed, inspected and also the HVAC contractor come out last week.



The HVAC guys are going to pan-off the part of the return that's now being used by the gas creating a new smaller return area below the green line and to the right of the yellow line. This area is of course is where the GE instructions say to mount the outlet *but* they picture a surface mount box.

There seems to be plenty of room for a flush mount box in the area shown above (blue box) and below (red arrow):



So I figured I'd run conduit and THHN to this new box location. Today I tried to pull one of the existing blue hot wires to get an idea of existing length but I cannot get it to pull through the conduit, I tried channel locks and hauling on it, won't budge.





Also, the diameter of the conduit isn't going to allow 4 #6 wires and I imagine the existing conduit is running through studs.

At the box and also the panel the neutral is the same cloth covered solid core so I don't think there is a hidden intermediate box.

I also wish people who do this wouldn't leave so much exposed feed wire at the main breaker.

I'm thinking maybe ditch the conduit? Use 6/3 NM-B to the new recessed box? I still need to pull that new cable somehow. Suggestions?
 
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Old 03-04-15, 11:06 AM
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I got the conduit removed. New 6/3 NM-B pulled, about 8 feet of it. I'll be reusing the old panel knockout, metal NM clamp. Have new clamp for the receptacle box.

I assume the standard stapling requirements apply here, within 12" of the panel and box. Not sure exactly how I'll satisfy the every 4-1/2' requirement.
 
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Old 03-04-15, 11:12 AM
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Fished cables are not required to be secured where inaccessible.
 
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Old 03-04-15, 11:37 AM
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Fished cables are not required to be secured where inaccessible.
Ok, thanks. I assume I still need to staple within 12" of panel and receptacle even though cable is clamped at both. I'll need to go get some SE staples. Before I patch the drywall I'll be able to staple that close to the receptacle and no problem within 12" of panel.
 
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Old 03-04-15, 12:13 PM
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If the cable is accessible it needs to be secured within 12" of the box or receptacle.
 
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