Objectionable current question.

pipe_bender said:
Yes its a old building, there is a large new meterpack each apartment has a feeder from the meter pack. My boss concluded the code allows a old 3-wire range NEMA 10-50 (or dryer 10-30) receptacle to remain in a 'subpanel' with the local AHJ here, and it had previously passed an inspection.
Click to expand...
Does Boston allow independent egc to be run to the receptacle or is that what was amended out?
 
pipe_bender said:
Yes its an old building, there is a large new meterpack each apartment has a feeder from the meter pack. My boss concluded the code allows a old 3-wire range NEMA 10-50 (or dryer 10-30) receptacle to remain in a 'subpanel' with the local AHJ here, and it had previously passed an inspection.
Click to expand...
That’s weird because mass deleted 250.140(b)(5) so technically the only way a existing 3 wire range/drier feed can remain is if it originates at the service 🤷‍♂️
 
Jaybone812 said:
That’s weird because mass deleted 250.140(b)(5) so technically the only way a existing 3 wire range/drier feed can remain is if it originates at the service 🤷‍♂️
Click to expand...
The way 250.140(B)(4) reads to me is its a two clause sentence divided by a boolean OR at the comma with a compound AND in the 2nd clause. If the grounded conductor is insulated then (4) is stratified with no further stipulations. Its a odd sentence though.
EDIT I think I asked in the other thread why MA deleted 250.130(C) we have allot of members on here from MA do you @Jaybone812 or anyone else from MA know the reason?
 
Last edited:
tortuga said:
The way 250.140(B)(4) reads to me is its a two clause sentence divided by a boolean OR at the comma with a compound AND in the 2nd clause. If the grounded conductor is insulated then (4) is stratified with no further stipulations. Its a odd sentence though.
EDIT I think I asked in the other thread why MA deleted 250.130(C) we have allot of members on here from MA do you @Jaybone812 or anyone else from MA know the reason?
Click to expand...
you make a very valid point , after reading your comment then going back to 250.140(b)(4) I’m in complete agreement with your interpretation, if the grounded conductor is insulated it can originate from other than the service, and I feel the reason I overlooked that language because I’ve never actually come across an existing 3 wire range/dryer feed that used a insulated grounded conductor to bond the frame . It’s either been bare and part of a se cable assembly and compliant or they used the bare grounding conductor from a nm cable assembly for the violation
 
tortuga said:
The way 250.140(B)(4) reads to me is its a two clause sentence divided by a boolean OR at the comma with a compound AND in the 2nd clause. If the grounded conductor is insulated then (4) is stratified with no further stipulations. Its a odd sentence though.
EDIT I think I asked in the other thread why MA deleted 250.130(C) we have allot of members on here from MA do you @Jaybone812 or anyone else from MA know the reason?
Click to expand...
@tortuga i can only assume mass deleted 250.130(c) so they didn’t have to enforce its compliance when it was applicable which leaves gfci protection as the only available option which is much easier to enforce and prove has been done correctly, of course that’s only my opinion nothing concrete
 
Jaybone812 said:
you make a very valid point , after reading your comment then going back to 250.140(b)(4) I’m in complete agreement with your interpretation, if the grounded conductor is insulated it can originate from other than the service, and I feel the reason I overlooked that language because I’ve never actually come across an existing 3 wire range/dryer feed that used a insulated grounded conductor to bond the frame . It’s either been bare and part of a se cable assembly and compliant or they used the bare grounding conductor from a nm cable assembly for the violation
Click to expand...
I have run into it. They made 10 3 romex with red black and white. It was made until the early 90s even though most went to SE cable before that. There was a lot of cloth romex that had it and the next most common I've seen is white sheathed stuff. I've seen the 10 with no ground way more than the 6 3 or 8 3 romex no ground.
 
Jaybone812 said:
@tortuga i can only assume mass deleted 250.130(c) so they didn’t have to enforce its compliance when it was applicable which leaves gfci protection as the only available option
Click to expand...
I highly suspect MA has this in their code in error because from 62' -93' the code allowed you to ground a receptacle to any point on a cold water pipe, and I think the MA ban goes back to banning that. In '93 the code language changed to what we know 250.130(C) as today and MA should have dropped the ban in '93.

In that other thread on objectionable current the most economical way to eliminate the N-G bond in a combo gas/electric range (or several ranges in that thread) is to run a suitable bare or green ground wire off the GEC to the range receptacle and convert a old range receptacle to a from the old '3-wire' 10-50 to a '4-wire' 14-50 .
I don't think can be accomplished with a 2P GFCI breaker on the range circuit.
I'd say if a state AHJ wants to eliminate situations like that keep 250.130(c) and delete 250.140(b) entirely if a state did that it would nudge appliance manufacturers to make a straight rated range (240V instead of 120/240) if they dont already.
Then a combo gas/electric range on say common 3-wire SE cable could convert to a 6-50 from a 10-50.
 
Last edited:
Here is a photo from a gas/electric range install, (I cant remember what the square is for must have been important at the time). The homeowner retired from owning a restaurant and got a nice range that had a gas 6 burner cooktop and the oven electric. The old NEMA 10-50 was in a odd box like a octagon box and had to be removed, and a green wire was pulled back to the GES per 250.130(C) so a 14-50 could be installed. the old wire was in fine shape other wise it would be rewired, it has a insulated neutral.
I suspect the 120V was only needed for the oven light and the gas controls and i am sure the manufacturers could make these to just be '240' eliminating the need for this 4-wire circus. I did not cut the hole in the wall, I believe the GC used the boot method of making the hole.gas_elect_range_s.jpg
 
ptonsparky said:
I started in 76. I never used any thing that did not have an insulated grounded conductor for ranges or dryers. Things are different in various parts of the country.
Click to expand...
I remember the 10-3 or 8-3 without a bare equipment ground we had to say 'With ground' to the counter guy or we'd get no bare wire.
Not sure when they quit making that but I still say 'with ground' when ordering NM and the parts counter guy gets a kick out of that.
 
You must log in or register to reply here.
Top