Old houses , 406.4(D)(2)(c) and 250.114

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drcampbell

drcampbell

Senior Member
Location
The Motor City, Michigan USA
Occupation
Registered Professional Engineer
Situation: Old house with 2-wire NM cable concealed in the walls, not feasible to replace the cable or add a ground wire.

406.4(D)(2)(c) seems to permit the use of 3-conductor grounding-type receptacles if they're ground-fault protected and labeled.
But 250.114 seems to require certain appliances to be grounded, apparently without exceptions.

Two questions come to mind:
Does anybody know of a source of cover plates permanently engraved with the required messages "GFCI Protected" and "No Equipment Ground"? Sharpies look unprofessional and Post-It notes lack permanence.

Does 250.114 supersede 406.4(D)(2)(c), and if so, in the case of a non-double-insulated window air conditioner (among other appliances) with a 3-wire cord and a 3-conductor plug,
how is the average homeowner/tenant supposed to know that the normally non-current-carrying metals parts shall be connected to an equipment-grounding conductor, and they're not supposed to plug it into a 3-conductor receptacle so labeled?
 
drcampbell said:
Does anybody know of a source of cover plates permanently engraved with the required messages "GFCI Protected" and "No Equipment Ground"? Sharpies look unprofessional and Post-It notes lack permanence.
Click to expand...

No but GFCI receps come with those stickers. Or Wal mart has a label maker for $25. Yeah its a stupid requirement. Non electricians have no idea what that means. I remember seeing some of those label outlets as a teenager before I got into electrical and had no idea what it meant :?:
 
drcampbell said:
..Does 250.114 supersede 406.4(D)(2)(c)..
Click to expand...
Notice 250.114 is limited to “Equipment.” Not branch circuits. The authority of 250.114 ends at the appliance cord and plug, in agreement with NRTL listing requirements for appliance construction requirements.

406.4(D) prevails, since a 3-prong corded appliances with low level fault is extnguished near 6ma with class-A GFCI protection, and saves lives long before a grounding wire can overload the 20A fuse.
 
I've passed so many of these with DF's , but they are not the end all cure for no EGC

Wasn't there a recent change that allowed us to utilize any available ECG from proximal circutry?

I can't seem to find it....:(

~RJ~
 
drcampbell said:
Situation: Old house with 2-wire NM cable concealed in the walls, not feasible to replace the cable or add a ground wire.

406.4(D)(2)(c) seems to permit the use of 3-conductor grounding-type receptacles if they're ground-fault protected and labeled.
But 250.114 seems to require certain appliances to be grounded, apparently without exceptions.

Two questions come to mind:
Does anybody know of a source of cover plates permanently engraved with the required messages "GFCI Protected" and "No Equipment Ground"? Sharpies look unprofessional and Post-It notes lack permanence.

Does 250.114 supersede 406.4(D)(2)(c), and if so, in the case of a non-double-insulated window air conditioner (among other appliances) with a 3-wire cord and a 3-conductor plug,
how is the average homeowner/tenant supposed to know that the normally non-current-carrying metals parts shall be connected to an equipment-grounding conductor, and they're not supposed to plug it into a 3-conductor receptacle so labeled?
Click to expand...
Just out of interest, how old is old?
 
This question has come up more than once, but the house we're currently working on was probably built in the 1920s (some pre-NEMA receptacles, bare-bulb ceiling light fixtures, tar-impregnated cotton sleeves) and upgraded in the 1940s or 1950s. (knotty-pine finished basement, 12-circuit fuseboxes)
 
drcampbell said:
This question has come up more than once, but the house we're currently working on was probably built in the 1920s (some pre-NEMA receptacles, bare-bulb ceiling light fixtures, tar-impregnated cotton sleeves) and upgraded in the 1940s or 1950s. (knotty-pine finished basement, 12-circuit fuseboxes)
Click to expand...

Is this house Downriver, or possibly in Dearborn? I do most of my work in Livonia, and most homes are built in 1950 or later. It's the 1950-56 ones that have the problem with wiring lacking an EGC.
 
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