opinions needed

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g-and-h_electric

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northern illinois
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supervising electrician
Hey all:

I am doing a small partial kitchen remodel. Basically relocation of a few receptacles, and adding a couple pendant lights. Circuiting for the countertop, refrig, and microwave are actually correct, and adequate.

The electric range receptacle is my "issue". As I am in the Chicago area, it is wired with "greenfield" which goes into the basement and terminates in the old panel box (now a junction box, as the service was updated about 25 years ago). There is no separate grounding conductor run in it (this was common years ago). My quandary is this.... The customer is getting a new range, the old receptacle is a NEMA 10-50 3 wire non grounded. I am thinking that the raceway is adequate for the ground, and I should install a NEMA 14-50 4-wire receptacle.

Anyone see a reason to NOT go with the 4-wire?

Thank you.


Howard
 
The standard procedure is, if you're using an existing circuit, to use the matching plug and cord, and wire the bonding jumper in the range's wiring compartment to suit.

As for the flex, as long as there is an insulated neutral conductor (or the neutral of SE cable), the neutral is doing double duty as the EGC, not the flex; it's just protection.

No, there's no reason not to add an EGC and change the receptacle and associated parts, other than cost, and it really is a safety improvement to do so. So, I vote yes.
 
Adding the insulated ground is not an option for several reasons (none of them being cost related). First is the greenfield is (get this) 1/2 with 2 #6, 1 #8, and lord knows how it gets upstairs from the basement, which leads me to the second item... the basement is finished with a drywall ceiling.

I guess I will be bonding the neutral, and using a 3-wire connection, tho when the greenfield was installed it was common practice here to use the flex as the equipment ground without a separate conductor for sizes larger than 3/8



Howard
 
g-and-h_electric said:
Adding the insulated ground is not an option for several reasons (none of them being cost related). First is the greenfield is (get this) 1/2 with 2 #6, 1 #8, and lord knows how it gets upstairs from the basement, which leads me to the second item... the basement is finished with a drywall ceiling....
Click to expand...
A 10AWG thhn should fit in there just fine.
 
FMC can only be used as an EGC if it meets all conditions of 250.118(5).
 
g-and-h_electric said:
Hey all:

I am doing a small partial kitchen remodel. Basically relocation of a few receptacles, and adding a couple pendant lights. Circuiting for the countertop, refrig, and microwave are actually correct, and adequate.

The electric range receptacle is my "issue". As I am in the Chicago area, it is wired with "greenfield" which goes into the basement and terminates in the old panel box (now a junction box, as the service was updated about 25 years ago). There is no separate grounding conductor run in it (this was common years ago). My quandary is this.... The customer is getting a new range, the old receptacle is a NEMA 10-50 3 wire non grounded. I am thinking that the raceway is adequate for the ground, and I should install a NEMA 14-50 4-wire receptacle.

Anyone see a reason to NOT go with the 4-wire?

Thank you.


Howard
Click to expand...
1. Am I understanding that you would like to use the raceway of the Greenfield mc as the grounding conductor? Not sure if that particular cable meets code requirements for that, not all MC did or does. If it does then concern would be "knowing" a securely bonded connection between appliance connection and panel box, if you intend to use sheathing as the grounding conductor.
2. Or are you suggesting, (your response #3), to use the sheathing of the Greenfield as a FMC, and pulling new thhn through it as a raceway? Better check code for conduit fill for required wire size, if you need 50A the wire would exceed for 1/2" FMC, not sure of actual dimensions of the Greenfield compared to FMC, or whether it can be pulled thru.
 
If the FMC meets the requirements for an EGC as greentagger mentioned then you can use it. If not you're permitted to reuse the 3 wire circuit with the bonded neutral in the range.
 
you guys are ABSOLUTELY correct! .... 3- wire it is.

I read various current versions of the NEC, 250.118, and found that the flex as installed is not suitable as an EGC. I went back to a 1987 handbook, and found that even then it was not allowed..... Geez, I was taught wrong, and did it wrong for many years.

Thank you for the guidance, and the education!


Howard
 
It was not just "greenfield", but 1/2" with 2"6, 1#8. And fished (I think) above the now finished basement drywall ceiling..... chopping that open was not an option based on the scope of work in the kitchen (the sink, dishwasher, and disposer are staying where they are) SO no plumbing is being done, and I couldnt find an "excuse" to chop ceiling.
 
Guys, it definitely came empty, and my predecessor put the wires in........ 2 blue #6, and 1 #8 RED (not even marked as the neutral/ ground). Funniest thing is that the original work was allegedly done by a guy I knew that had a great reputation..... (I guess we all have our days.....)


Howard
 
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