Stove/dryer receptacles

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RatherBeFishin

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Electrical apprentice
Two questions here,

Was in a house where homeowner had a three wire dryer receptacle and there was a 10/3 in the box where the guy had the neutral and bare ground together on the w neutral terminal. Did the right thing and changed the cord to a 4 wire and 4 wire receptacle but homeowner wanted to leave the 3 prong cord and outlet as is. Thinking about it would it have been alright to leave the insulated neutral on the receptacle and move the bare ground onto the ground screw of the metal box and leave the three wire set up as is?

Second, If se cable was allowed to serve three wire stoves and receptacles and someone used a metal box and raised ring with device how was that ever allowed? There would be no path back for an ungrounded receptacle if there were a short from hot to ground onto the box or cover. Small area to get shocked off of just the box but still
 
In the old days the neutral served as a dual purpose conductor. The neutral and ground were connected together so there was no separate ground.

<y question is why did the owner want to leave the 3 wire cord. If you didn't do any work on this it would have been fine to leave it. If you moved it then Imo you need to use a 4 wire setup. Don't let the homeowner dictate code to you.
 
Heats_in_da_tools_kid said:
Thinking about it would it have been alright to leave the insulated neutral on the receptacle and move the bare ground onto the ground screw of the metal box and leave the three wire set up as is?
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No, as the dryer frame would still have been bonded to neutral instead of ground, and 250.140 Exception would not apply as you did have an EGC in the receptacle box.

Heats_in_da_tools_kid said:
Second, If se cable was allowed to serve three wire stoves and receptacles and someone used a metal box and raised ring with device how was that ever allowed? There would be no path back for an ungrounded receptacle if there were a short from hot to ground onto the box or cover. Small area to get shocked off of just the box but still
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250.140 Exception would require that the metal box be bonded to the neutral.

Cheers, Wayne
 
wwhitney said:
No, as the dryer frame would still have been bonded to neutral instead of ground, and 250.140 Exception would not apply as you did have an EGC in the receptacle box.


250.140 Exception would require that the metal box be bonded to the neutral.

Cheers, Wayne
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Thanks Wayne, first answer makes perfect sense but to your second why would we want to bond neutral to ground and create another parallel path for neutral current to flow? If ground is bonded to neural whatever current is on that neutral will now also be on the metal box and metal cover no? But then with se cable being allowed on dryer rec’s i don’t understand the logic of that if someone used a metal box and metal cover with no egc present a fault can’t clear. Maybe that’s why surface mount plastic cover stove/dryer outlets were used even though the back plates were metal
 
wwhitney said:
In your question, the metal box was isolated so would otherwise be floating. By bonding it to the neutral, no parallel paths are created.

Cheers, Wayne
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I’m sorry im not sure what you mean. I’m talking about a non grounding type receptacle with the bare neutral on the receptacle. I don’t understand how a ground fault would clear if a hot wire came in contact with the box unless you ran a separate ground from the panel or from another outlet ground out of that same panel. How would you not have current flowing on a metal box/ cover if you bonded neutral to the box? I understand grounding the frame to neutral because there was no ground in the dryer but not sure why you’d wanna apply neutral current onto a metal object. Unless I’m missing something correct me please
 
Heats_in_da_tools_kid said:
I’m sorry im not sure what you mean.
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Below is a very crude drawing. Red/White/Black are L/N/L, blue is the metal box or metal range frame. The left hand side is the 3-wire/no EGC supply. The box shows a hardwired connection, but it could be receptacle and plug, makes no difference.

In the absence of an EGC, the intentional bond of the neutral to the range frame allows a fault path should a hot conductor fault to the range. Works the same way with the metal junction box. Only allowed on existing installations per 250.140 Exception.

Cheers, Wayne

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Thanks Wayne! Going forward if I ever come across a dryer/stove outlet wired with se cable or Romex with no ground I’ll bring a tail off the neutral terminal to bond the box. At first I thought it would create unwanted current on the cover in the event of a ground fault but electricity wants to find the source so that bond makes slot of sense to me now!
 
wwhitney said:
Below is a very crude drawing. Red/White/Black are L/N/L, blue is the metal box or metal range frame. The left hand side is the 3-wire/no EGC supply. The box shows a hardwired connection, but it could be receptacle and plug, makes no difference.

In the absence of an EGC, the intentional bond of the neutral to the range frame allows a fault path should a hot conductor fault to the range. Works the same way with the metal junction box. Only allowed on existing installations per 250.140 Exception.

Cheers, Wayne

View attachment 2562445
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Sorry Wayne, one more for you on this matter lol. So just wanted to be sure in this scenario my wiring methods would be proper. Youre really only allowed to have an insulated neutral, or the neutral of bare seu cable was allowed also allowed on dryer receptacles per code (forget the section but it’s there).

How would one properly bond the box to the device if there’s no spot for a ground on a three wire non grounding type device? Would it be ok to bring another piece of bare aluminum to match the neutral wire to the back of the box off of that same terminal on that device? Couldn’t imagine if fitting under that same terminal. Or perhaps a smaller piece of bare insulated number 10 with some no alox? Mind you I’m talking if a new 10/3 with ground couldn’t be ran and you have to do your best with the existing wiring whether it be 10/2 with bare copper, 10/2 with insulated neutral, or seu with concentric neutral. Thank you!
 
RatherBeFishin said:
How would one properly bond the box to the device if there’s no spot for a ground on a three wire non grounding type device?
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You don't bond the box to the device, you always bond the box to the wiring method. The bond for a box needs to stay in place even if the receptacle is temporarily removed, etc. So in the case under discussion, you'd connect the branch circuit neutral conductor to a bonding screw tapped to the box, or some other bonding means for a box (those clips, or something else I'm not aware of). Same way you bond enclosures of service equipment upstream of the service disconnect.

Cheers, Wayne
 
wwhitney said:
You don't bond the box to the device, you always bond the box to the wiring method. The bond for a box needs to stay in place even if the receptacle is temporarily removed, etc. So in the case under discussion, you'd connect the branch circuit neutral conductor to a bonding screw tapped to the box, or some other bonding means for a box (those clips, or something else I'm not aware of). Same way you bond enclosures of service equipment upstream of the service disconnect.

Cheers, Wayne
wwhitney said:
You don't bond the box to the device, you always bond the box to the wiring method. The bond for a box needs to stay in place even if the receptacle is temporarily removed, etc. So in the case under discussion, you'd connect the branch circuit neutral conductor to a bonding screw tapped to the box, or some other bonding means for a box (those clips, or something else I'm not aware of). Same way you bond enclosures of service equipment upstream of the service disconnect.

Cheers, Wayne
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Got it, you made it click for me. Lay in lug so the wire can hit the lug tapped to the back of box and and then land on the device neutral screw would be perfect, then no pigtail needed. Thumbs up
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