250.140 frames of ranges

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Peter Furrow

Peter Furrow

We’re not born humble, we’re born to be humbled
Location
Cape canaveral Fl
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Electrical contractor
My brother is electrical contractor in Colorado and I am an electrical contractor in Florida. From our conversations Colorado seems to “strain the gnat” on the NEC . For example, my brother recently failed an inspection after installing a new 200 amp outdoor disconnect (residential).
The indoor electrical panel was existing.
The range & dryer had an existing three wire system. Because he implemented a new outdoor main disconnect which previously just had a meter can, the inspector now is obligating the homeowner to upgrade to a four wire system for the range and dryer. He said that if the range and the dryer went to the service equipment it would be permissible.
In 250.140 it allows a neutral to case connection .
In the 2020 handbook (commentary) it does talk about type SE cables supplying ranges that were required to originate at the service equipment to avoid neutral current from downstream panel boards being imposed on metal objects such as pipes and ducts. But nowhere in the code does it say that these 3-wire circuits have to originate at the service today.
If I have an indoor electrical panel that is fed with a four wire SER cable and The range circuit is fed with a three wire branch circuit with a neutral to case bond ..,that should be permissible? Correct? Why would the 3-wire rang circuit have to go all the way back to the service equipment?
Why would this Colorado Inspector obligate the electrician to upgrade to a four wire system when all he was doing was installing a new outdoor disconnect?
 
The rule for type SE conductors with a bare neutral is that it must originate from the main service panel. If the inside panel is now a subpanel and SE with a bare neutral was used, then the inspector is within his rights to require upgrading. The reason that I heard for not allowing the bare neutral in a subpanel is there is a chance the bare neutral could contact a conductive object (metallic) and cause unwanted current on all metallic objects along the path.
With that said, most inspectors here will allow us to tape the bare neutral in the panel and not have to change it.
Also, if your brother's job had an insulated neutral, then it is compliant to leave as is.
 
“The reason that I heard for not allowing the bare neutral in a subpanel is there is a chance the bare neutral could contact a conductive object (metallic) and cause unwanted current on all metallic objects along the path.
With that said, most inspectors here will allow us to tape the bare neutral in the panel and not have to change it.
Also, if your brother's job had an insulated neutral, then it is compliant to leave as is.”
 
Peter Furrow said:
“The reason that I heard for not allowing the bare neutral in a subpanel is there is a chance the bare neutral could contact a conductive object (metallic) and cause unwanted current on all metallic objects along the path.
With that said, most inspectors here will allow us to tape the bare neutral in the panel and not have to change it.
Also, if your brother's job had an insulated neutral, then it is compliant to leave as is.”
Click to expand...

Thank you for clarifying that.


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When the new main was added, was the original 3-wire service cable replaced with a 4-wire feeder?

It should have been, along with separating the neutrals and grounds, as with any sub-panel.

And, yes, the 3-wire major appliance circuits should have been re-wired as 4-wire circuits.

Present code doesn't say that 3-wire circuit need originate in the main because they're no longer allowed.
 
Yes . 4-wire SER feeder cable is present.
Neutrals and grounds are separated in the indoor panel. Main bonding is at the service main disconnect .
Little Bill (moderator) Explained it nicely when he said that “the inspector is within his rights to require upgrading”. The bare neutral of the range circuit would make contact with the metallic cabinet (panel) Creating objectionable current on the equipment grounding conductor. His suggestion was to tape the uninsulated neutral & with tape some inspectors may not obligate the upgrade to
4- wire range circuit.
My point in all this is that Florida is much more lenient on this matter. But after discussing it on this form I do understand the hazards.
 
In my area the AHJ makes us change it out if it is a short to medium run. Depends on your AHJ. Most of the time I try and change it for liability reason.
 
As this keeps coming up electricians may want to stop adding disconnects with fuses or breakers, and just add a non-fused disconnect to met this requirement. Keeping the current location for the service disconnect will simplify these installations
 
The scary thing is how many electricians or homeowners have no idea about removing the bonding strap on a dryer when you have a 4- wire.

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david said:
As this keeps coming up electricians may want to stop adding disconnects with fuses or breakers, and just add a non-fused disconnect to met this requirement. Keeping the current location for the service disconnect will simplify these installations
Click to expand...
A non fused disconnect is still the disconnect.

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Ohms law said:
The scary thing is how many electricians or homeowners have no idea about removing the bonding strap on a dryer when you have a 4- wire.

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Click to expand...

I agree. But let’s just say that you have a
4- wire dryer cord & a 4-wire dryer receptacle.
However, you only have three wires in the junction box because the circuit is a three wire system. (This scenario does come up for homeowners when their appliances are delivered. Sears and other companies have been known to send their appliances out with the neutral to case connection and still provide a 4-wire cord . Mike Holt mentioned in his bonding and grounding video under 250.140 section that he contacted the company and also UL regarding this matter but nothing was changed.)
But even if that was the case, There would be no objectionable current on the equipment grounding conductor in the circuit cable because there is no equipment grounding conductor , its 3-wire. The only objectionable current would actually be on the equipment grounding conductor in the appliance cord only.


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They enforce that here, they allow us to use the method where your allowed to tape the bare in the SE cable white and pull a #10 Green from:
250.130(C) said:
Any accessible point on the grounding electrode system
as described in 250.50
Click to expand...

Funny story: I had to do that for a apartment once, and it was going to be a bear of a job, and I first opened up the simple apartment range to remove the cord and there were no appliance wires on the white terminal!
Just the green wire to the frame.
I looked at the oven light and it was this little funny 240V candelabra type bulb.
I found a appliance schematic in an plastic pocket inside the cover and sure enough no neutral.
I put a NEMA 6-50 cord and receptacle on it job done.
The inspector wanted to see that schematic.
 
zbang said:
And that's the big question- is it now really a sub-panel? (4-wire feed, no SBJ, etc)
Click to expand...
Sub panel is not a NEC term.

It is either supplied by service conductors and contains the service disconnecting means or it is a feeder supplied panel. Feeder supplied is supposed to utilize separate EGC other than some previously allowed feeders to separate buildings. That allowance went away in 2008 NEC and is only an exception for previously allowed installations to remain that way. A feeder in same building as it originates was never allowed (at least in last 70-80 years AFAIK) to use same conductor for grounded and equipment grounding conductor purposes.
 
zbang said:
No, but most people know what it means.
Click to expand...
Well in a dwelling it is usually either the service panel or it is feeder supplied (AKA "subpanel")

If you would have a separately derived system then you can possibly have the first disconnecting means be a main breaker in a panel and have the neutral-ground bond there and is basically like a service panel.
 
rjniles said:
A non fused disconnect is still the disconnect.

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Click to expand...
A non fused disconnect satisfies the requirement without changing the service disconnect location. The power company has required a non fused safety disconnect ahead of 480/277 line voltage metering here for years this installation is not nothing new
 
I bet there are lots of ranges you can put on a 6-50 these days.
1590202436561.png

Ammeter a neutral on ranges when ever you get the chance, I have been doing it for a decade (since around when we had this thread 10 years ago here ).
I have found one from the 1940's that did.
I would be amazed to see a range manufactured in 2020 that uses the neutral for heating or anything other than the electronic display and light.
 
tortuga said:
I would be amazed to see a range manufactured in 2020 that uses the neutral for heating or anything other than the electronic display and light.
Click to expand...
Those loads were more than enough to severely injure a customer's child when he bridged the gap between the sink and the 3-wire-supplied range, and I found the cord's neutral wire to have pulled out of the crimped-on terminal in the wiring compartment.

They told me the light and clock had stopped working a few days before. What I found under the kitchen was not much better.

As part of a kitchen remodel, someone removed the receptacle, took the cord under the house, passed the terminal end of the cord through a new hole in the floor and back into the range, wrapped one strand of each range circuit cable through the hole in each plug blade, and taped them.

Because the range was moved farther from the panel, the whole thing was barely long enough to reach, putting a constant pull on the terminations. Of course, the cable clamp was missing, too.
 
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