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I've had a couple of instances lately that involved existing branch circuit wiring for ranges and clothes dryers in condos. In both instances the equipment was supplied from the service panels in the condos which were not service equipment. The wiring for the ranges and dryers was NM cable with two insulated conductors and and uninsulated EGC. The wiring in both cases was inaccessible.

In the case of the dryer, the 3 slot receptacle was worn out and had to be replaced. In the case of the range, a new range was procured and had to be hooked-up via a 3 slot receptacle. In both cases I connected the frames to the EGC and for the range, connected the range neutral to the EGC also.

The requirements for existing installations spelled out in NEC 250.140 clearly were not met. Did I really screw up by not insisting that the branch circuit wiring be replaced or was what I did OK?
 

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RIP 1959-2015
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I've had a couple of instances lately that involved existing branch circuit wiring for ranges and clothes dryers in condos. In both instances the equipment was supplied from the service panels in the condos which were not service equipment. The wiring for the ranges and dryers was NM cable with two insulated conductors and and uninsulated EGC. The wiring in both cases was inaccessible.

In the case of the dryer, the 3 slot receptacle was worn out and had to be replaced. In the case of the range, a new range was procured and had to be hooked-up via a 3 slot receptacle. In both cases I connected the frames to the EGC and for the range, connected the range neutral to the EGC also.

The requirements for existing installations spelled out in NEC 250.140 clearly were not met. Did I really screw up by not insisting that the branch circuit wiring be replaced or was what I did OK?

From the 2014 NEC.

250.140 Frames of Ranges and Clothes Dryers. Frames of electric ranges, wall-mounted ovens, counter-mounted cooking units, clothes dryers, and outlet or junction boxes that are part of the circuit for these appliances shall be connected to the equipment grounding conductor in the manner specified by 250.134 or 250.138.
Exception:  For existing branch-circuit installations only where an equipment grounding conductor is not present in the outlet or junction box, the frames of electric ranges, wall-mounted ovens, counter-mounted cooking units, clothes dryers, and outlet or junction boxes that are part of the circuit for these appliances shall be permitted to be connected to the grounded circuit conductor if all the following conditions are met.
(1) 
The supply circuit is 120/240-volt, single-phase, 3-wire; or 208Y/120-volt derived from a 3-phase, 4-wire, wye-connected system.
(2) 
The grounded conductor is not smaller than 10 AWG copper or 8 AWG aluminum.
(3) 
The grounded conductor is insulated, or the grounded conductor is uninsulated and part of a Type SE service-entrance cable and the branch circuit originates at the service equipment.
(4) 
Grounding contacts of receptacles furnished as part of the equipment are bonded to the equipment.



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If they used Romex originally then they did it wrong,if it's SE cable you're fine.

The next guy would have done the same thing and charged less,there is no way to win except to sell a new circuit,and it's a hard sell.
 

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Ok so, all of this worked fine for 75 years and now it's a problem. Did some thing change?
BTW, Sears came out and installed by new stove and connected it to my three wire receptacle using a three wire cord they installed. They didn't install the jumper from the neutral to ground. I found this out the next day standing barefoot on my slate floor, which is slab on grade, shocked the Crap outta me.
C
I changed to 4wire that morning. :thumbsup:
 

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I've seen a bunch of old cables for ranges and dryers that had two insulated conductors and a bare conductor, but were in a cloth covered cable. To me, these would be a romex (NM) cable, and not an SE cable, and was maybe ran like that in older homes because they did not need a neutral on older appliances (?). In those circumstances, you probably (technically) have to re-run the circuit with the appropriate 3 wire + a ground cable to satisfy the code.
 

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But here is the question, Where these circuits derived from a main panel or a sub panel? You would instantly need a 4 wire if a sub panel was their feed point meaning the original install was an existing violation.
 

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I've seen a bunch of old cables for ranges and dryers that had two insulated conductors and a bare conductor, but were in a cloth covered cable. To me, these would be a romex (NM) cable, and not an SE cable, and was maybe ran like that in older homes because they did not need a neutral on older appliances (?). In those circumstances, you probably (technically) have to re-run the circuit with the appropriate 3 wire + a ground cable to satisfy the code.
Probably every electric range or dryer, built for use in this country and Canada, used a neutral.
BTW, I had a lot of words with the Sears installers, regarding the proper connections for the power cords. :eek:
 

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Ok so, all of this worked fine for 75 years and now it's a problem. Did some thing change?
BTW, Sears came out and installed by new stove and connected it to my three wire receptacle using a three wire cord they installed. They didn't install the jumper from the neutral to ground. I found this out the next day standing barefoot on my slate floor, which is slab on grade, shocked the Crap outta me.
C
I changed to 4wire that morning. :thumbsup:
Assuming that the third wire in the cord was connected to the neutral terminal in the stove, you should not get a shock unless there is a problem within the stove.
 
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