Haywire circuits

[mc5w]

1.) National Electrical Code section 210.4

2.) New Text

3.) Proposal:

Haywire Circuits: Loads shall not be supplied by tapping one or more conductors of a branch circuit and 1 or more conductors of another branch circuit. 15-ampere to 50-ampere single-phase branch circuits shall be wired so that GFCI protection for people or equipment can be applied at or near the supply panelboard.

A nonmetallic sheathed cable type NM, NMC, or UF that is installed as a retrofit with nonmetallic boxes to correct haywiring shall be permitted to take any convenient route.

In new installations where 2 or 3 nonmetallic sheathed cables types NM, NMC, SE, or UF are installed in accordance with 300.3(B)(3) to provide 4 to 9 current carrying conductors between 2 boxes shall be installed within 4 inches ( 100 millimeters ) of each other and shall pass entirely on 1 side of any metal object such as plumbing or ductwork.

4.) Justification and Reasoning:

Some electricians are still wiring stairway lights by tapping a hot wire on the lower floor, going through the 3-ways and 4-ways with 2-wire with ground type NM cable, and then tapping a neutral that is on a different circuit on the upper floor. This creates unexpected shared neutral circuits that can be harzardous to service and the shared neutral could be overloaded if both overcurrent devices are somehow on the same phase. Haywire circuits also make installation of ground fault circuit interrupters and arc fault circuit interrupters for the whole branch circuit or a large part of it impossible without having to do major extra work.

There is no excuse for NOT doing light switches by the book. Haywiring was done back in the days of knob and tube wiring where a #6 common neutral wire ran the length of a floor and is an obsolete concept.

When 2 or 3 cables are installed to serve the logical equivalent of a single cables then the workmanship needs to be done similar to a single cable.

[ April 17, 2005, 02:28 AM: Message edited by: mc5w ]

 

[charlie]

Re: Haywire circuits

I like the concept but it is way to verbose. It needs to cut down to a single line or two and get rid of the slang term "haywiring".

 

[George Stolz]

Re: Haywire circuits

I'm late for work, maybe that's the problem, but I don't understand any of this except for your intent.

But I AM late...

 

[don_resqcapt19]

Re: Haywire circuits

Haywire Circuits: Loads shall not be supplied by tapping one or more conductors of a branch circuit and 1 or more conductors of another branch circuit.

Doesn't 300.3(B) already cover this issue.

15-ampere to 50-ampere single-phase branch circuits shall be wired so that GFCI protection for people or equipment can be applied at or near the supply panelboard.

That appeas to be a design issue, not a code issue.

In new installations where 2 or 3 nonmetallic sheathed cables types NM, NMC, or UF are installed to provide 4 to 9 current carrying conductors between 2 boxes shall be installed within 4 inches ( 100 millimeters ) of each other and shall pass entirely on 1 side of any metal object such as plumbing or ductwork

The seperation of the cables does not cause any problems as long as the conductors for a circuit are not in two or more cables.
Don

[ April 14, 2005, 11:49 AM: Message edited by: don_resqcapt19 ]

 

[izak]

Re: Haywire circuits

QUOTE *** The seperation of the cables does not cause any problems as long as the conductors for a circuit are not in two or more cables.
Don


What i do not understand about that is how are residential electricians able to get away with running 'travelers' in a seperate cable by themselves, sometimes as much as 20 or 30 feet away from the cable containing the grounded conductor...

i mean, is the fact that its not in a metal conduit make That much difference? is it safer to do that in NM??

 

[mc5w]

Re: Haywire circuits

I tweaked the proposal a little.

300.3(B)(3) theoretically allows 2 or 3 nonmetallic sheathed cables to provide 4 to 9 conductors plus equipment ground between 2 boxes because obtaining a single cable is more expensive ( 12/4 about twice as much as two 12/2 for materials ) or impossible. Also, running concealed conduit in a mainly romex system can be a real pain in a certain body part. Smurf tube has excessive internal friction when doing wire pulling.

300.20 does not address what happens when current in 1 cable is on 1 side of a steel duct and the current goes back through another cable on the other side of the duct.

Something known as a Hitlock(R) when it was under patent allows two 12/2 cables to enter a metal box through te same knockout. This would allow a circuit to be wired using 2 hot wires and 2 neutrals.

I have also seen instance where Carter-wired 3-ways ( a method now banned for new work ) is supplied with 2 hot wires and 2 neutrals. This is how you get 240 volts in a 3-wat switching circuit. This is also how you get something that is not as deenergized as advertized.

Also, a little bit of redundancy does not hurt. When 1 Code section refers to other Code sections then National Electrical Code starts to read like stereo directions.

 

[George Stolz]

Re: Haywire circuits

Michael, I don't know about the others, but I find it hard to see progress in this kind of thread when you edit the original with the updates. I think Holt's has ample space for you to repost it with changes.

 

[iwire]

Re: Haywire circuits

Originally posted by georgestolz:
Michael, I don't know about the others, but I find it hard to see progress in this kind of thread when you edit the original with the updates. I think Holt's has ample space for you to repost it with changes.

I think that is an excellent point.

Each time a change is made make it in a new post to the same thread with the changes in bold or italics so we can see how the proposal is evolving.

Perhaps it should be a rule of this forum section.

JMO, Bob

 

[George Stolz]

Re: Haywire circuits

Morning, Bob.

Stretched my legs and thought I'd better elaborate on the "back door" bit. A traveller will induce a small amount of voltage onto it's mate, but I've never encountered a situation where the induced voltage is enough to feel a tingle, or light a light bulb.

You seem to be (justifiably) concerned with installers stealing a neutral from another circuit, and causing a neutral current danger by direct connection of the conductors. Your proposal should deal directly with this problem, using concise language.

 

[mc5w]

Re: Haywire circuits

I have never heard any kind of official term for this kind of circuit. I do not have a better term than haywire. I would need some help from you guys as to an official term.

The anonymous shared neutral hazard and the induction heating hazard are two different hazards. The former is a direct electric shock hazard and both my buddies and I have had this problem when changing residential panelboards because we usually like to get some of the lighhts going again as we are working.

Limiting the separation of the cables is more of a workmanship issue and to also keep some ingenious fool from coming up with some crazy circuit. I am not too worried about induction heating around ductwork and so forth but more of a matter that if 2 or 3 nonmetallic sheathed cables are installed to serve the logical purpose of 1 cable then they need to be in close proximity to each other. That is, a group of cables that serve the purpose of a single cable need to installed in a similar manner to a single cable.

 

[George Stolz]

Re: Haywire circuits

Sometimes the best term is no term at all. A description of the configuration of the conductors would probably take less space and have fewer loopholes, than creating a term and using it.

If you are dealing with two different problems, perhaps it would be best to split up your two ideas into seperate proposals. That would make it clearer, and then you've probably doubled your chances of succeeding.

If you want to close the door on the NM loophole, perhaps it belongs in 334? 300.20 is very clear on it's intent at the moment, despite it's similarity to what you're wanting to do.

I question the choice of 210.4, because the only item it deals with is multiwire circuits. If your stolen neutral is on the same phase, then 210.4 wouldn't be in the same ballpark anymore.

IMO, I think the existing system isn't perfect, but I enjoy having the option of doing something ill-advised to get out of a pinch. I believe the EMF side of this problem is more compelling than the stolen neutral aspect of it. IMO.

 

[mc5w]

Re: Haywire circuits

Revised Proposal:

1) Code section 210.4

2) New text

3) Proposal:

210.4(C) Anonymous Shared Conductor Circuits also known as Haywire Circuits. Loads shall not be supplied by tapping 1 or more conductors of a 2-wire or multiwire branch circuit and 1 or more conductors of another 2-wire or multiwire branch circuit. Grounded circuit conductors and neutral conductors of differnet circuits shall not be interconnected. Where 2 or more circuits are in the same box they shall be numbered or otherwise identified as different circuits.

A nonmetallic sheathed cable type NM, NMC, or UF installed as a retrofit to correct an anonymous shared conductor a.k.a. haywire circuit shall be permitted to take any convenient path provided that an induction heating hazard is not created.

Where 2 or 3 nometallic sheathed cables type NM, NMC, UF, or SE are installed inaccordance with 300.3(B)(3) to provide 4 to 9 insulated conductors between 2 boxes they shall be grouped together. Proximity of the cables shall be reasonable and they shall not be required to pass through the same hole in wooden framing members.

 

[George Stolz]

Re: Haywire circuits

Originally posted by mc5w:
Revised Proposal:

1) Code section 210.4

2) New text

3) Proposal:

210.4(C) Anonymous Shared Conductor Circuits also known as Haywire Circuits. Loads shall not be supplied by tapping 1 or more conductors of a 2-wire or multiwire branch circuit and 1 or more conductors of another 2-wire or multiwire branch circuit. Grounded circuit conductors and neutral conductors of differnet circuits shall not be interconnected. Where 2 or more circuits are in the same box they shall be numbered or otherwise identified as different circuits.

A nonmetallic sheathed cable type NM, NMC, or UF installed as a retrofit to correct an anonymous shared conductor a.k.a. haywire circuit shall be permitted to take any convenient path provided that an induction heating hazard is not created.

Where 2 or 3 nometallic sheathed cables type NM, NMC, UF, or SE are installed inaccordance with 300.3(B)(3) to provide 4 to 9 insulated conductors between 2 boxes they shall be grouped together. Proximity of the cables shall be reasonable and they shall not be required to pass through the same hole in wooden framing members.

Delete everything but the bold, and it's a go!