Neutral required in switch box?

[tom baker]

I was cleared by exception 1 but exception 2 has me curious:
I guess "open framing cavity" refers to situations like a computer-room floor or hanging-grid ceiling... but entering a switch box through a floor or ceiling? are we even allowed to place lighting switches there? (I know it is not ADA compliant unless the ceiling is below 42" high)

All kidding aside is this supposed to mean that if you have an unfinished attic or basement that exception 2 applies?

Framing cavity would be a 2x4 wall that you could get into later.

 

[ActionDave]

Framing cavity would be a 2x4 wall that you could get into later.

That is the way I read it too.

 

[renosteinke]

There are a thousand ways to run wires so that a light may be switched. I thnk it's clear that the intent of the code panel was to limit your choice to but one way.

That way is to wire from the panel, through the switches, and then to the light. Period. Just like you'd draw it on a ladder diagram. No more running direct to the light, then just sending a pair of wires out to the switch.

That's how I read it.

 

[kwired]

Lighted switches don't require a neutral... they run by a trickle of current through the light fixture, (if you remove the bulb or fixture the "lighted" switch stays dark)

404.2 has a comment that says it was added because of the increased use of electronic controls and timers.

Not if they are an indicating light that the load is "on". But I bet you knew that

 

[suemarkp]

There are a thousand ways to run wires so that a light may be switched. I thnk it's clear that the intent of the code panel was to limit your choice to but one way.

That way is to wire from the panel, through the switches, and then to the light. Period. Just like you'd draw it on a ladder diagram. No more running direct to the light, then just sending a pair of wires out to the switch.

You can still run direct to the light and then to a switch, but you'll need 14-3 to the switch so a neutral is there (assuming a non-3-way switching setup). In the days of incandescent lamps, I never thought running to the light fixture first was a smart thing to do -- too hot of an environment for what could potentially be a full load running through the power wires in that ceiling box. Now that lights are cool fluorescent/LED, there may not be much of a heating issue anymore.

 

[RustyShackleford]

Framing cavity would be a 2x4 wall that you could get into later.

What wall cavity CAN'T you get to later if you try hard enough ?

No more running direct to the light, then just sending a pair of wires out to the switch.

Correct, no simple switch-leg. But you can always run 3-wire for the switch leg and then include an outlet there by the switch.

 

[DaveTap]

Not if they are an indicating light that the load is "on". But I bet you knew that

Yep

 

[DaveTap]

Framing cavity would be a 2x4 wall that you could get into later.

Yes but framing cavity that is open at the top or bottom on the same floor level
Don't see that too often except computer room floors or offices with false ceilings.

Unless their idea of "open" is about a 1/2" hole?

 

[ActionDave]

Yes but framing cavity that is open at the top or bottom on the same floor level
Don't see that too often except computer room floors or offices with false ceilings.

Unless their idea of "open" is about a 1/2" hole?

Exception:
(2) Cable assemblies for switches controlling lighting loads
enter the box through a framing cavity that is open at
the top or bottom on the same floor level, or through a
wall, floor, or ceiling that is unfinished on one side.

You don't even need a hole. You only need to be able to make one from the attic or the crawl.

 

[RustyShackleford]

Exception:
(2) Cable assemblies for switches controlling lighting loads
enter the box through a framing cavity that is open at
the top or bottom on the same floor level, or through a
wall, floor, or ceiling that is unfinished on one side.

You don't even need a hole. You only need to be able to make one from the attic or the crawl.

That sure seems like a reasonable interpretation, but as always, for all practical purposes, it's up to the AHJ.

 

[mike9593]

can someone post art 404.2(C) nec 2011?

(C) Switches Controlling Lighting Loads.​

​

​

​

​

Whereswitches control lighting loads supplied by a grounded generalpurpose branch circuit, the grounded circuit conductorfor the controlled lighting circuit shall be provided at theswitch location.​

Exception: The grounded circuit conductor shall be permittedto be omitted from the switch enclosure where either ofthe following conditions in (1) or (2) apply1) Conductors for switches controlling lighting loads enterthe box through a raceway. The raceway shall have sufficientcross-sectional area to accommodate the extensionof the grounded circuit conductor of the lightingcircuit to the switch location whether or not the conductorsin the raceway are required to be increased in sizeto comply with​

​

​

​

310.15(B)(3)(a).(2) Cable assemblies for switches controlling lighting loadsenter the box through a framing cavity that is open atthe top or bottom on the same floor level, or through awall, floor, or ceiling that is unfinished on one side.​

Informational Note: The provision for a (future) groundedconductor is to complete a circuit path for electronic lightingcontrol devices.​

This section is new in the 2011​

​

​

​

Code. Many electronic lightingcontrol devices require a standby current to maintain theready state and detection capability of the device. This allowsimmediate switching of the load to the ?on? condition. Thesedevices require standby current when they are in the ?off ?state, that is, when there is no load current. Many of these devicesutilize the equipment grounding conductor for thestandby current flow. Prior to this requirement, a groundedconductor was not usually provided in the switch box forswitches controlling lighting loads, so these control devicesneeded to utilize the equipment grounding conductor to conductthe standby current. Occupancy sensors are permitted byUL 773A, Standard for Safety of Non-Industrial PhotoelectricSwitches for Lighting Control, to have a current of up to0.5 mA on the equipment grounding conductor. In fact, anumber of UL standards permit up to a 0.5 mA ground leakagecurrent as acknowledgment of an operational necessity.This is allowed because the function of an occupancy sensorrequires a low level standby current. The standard permits thiscurrent on the equipment grounding conductor because in atypical installation there may be no grounded circuit conductorin the switch box that can be used as the return conductorfor the standby current. The exception allows two scenariosunder which the grounded circuit conductor is not required. Inthe first scenario, the exception permits the conductor to beomitted in raceway installations where it is practical to add aconductor at the switch location in the future, if needed. Thesecond scenario allows the conductor to be omitted where theconstruction of the framing cavity in which the switch box islocated permits access through which the conductor can be​

run in the future.

 

[sketchy]

Does the neutral have to be from the same circuit? If I have 2 lighting circuits in the same box, one with a neutral and the other a dead end 3 wire for a separate circuit, is that legal?

 

[RustyShackleford]

Does the neutral have to be from the same circuit? If I have 2 lighting circuits in the same box, one with a neutral and the other a dead end 3 wire for a separate circuit, is that legal?

It doesn't seem like it should be, since the intent (as I understand it) is for the neutral to carry the return current for an occupancy sensor (or similar "smart" switch). If the neutral were from another circuit, then you'd essentially be forming a circuit with the ungrounded conductor from one circuit and the grounded conductor from a different circuit. Which has gotta be illegal, though I can't cite code right now. Of course, it's a pretty miniscule current ... The other issue is that it's not necessarily very easy to tell WHICH branch circuit a neutral belongs to.

In some situations there's no clean way to get the neutral there without 4-wire (e.g. neutral, hot, travelers). Fortunately 14-2-2 is becoming fairly easy to find, and this place sells 4-wire by the foot for a pretty reasonable price:

https://www.munroelectric.com/silve...Wire,NM.B.Cable.(Romex)&path=find&ds=dept&a=1

 

[Dennis Alwon]

Does the neutral have to be from the same circuit? If I have 2 lighting circuits in the same box, one with a neutral and the other a dead end 3 wire for a separate circuit, is that legal?

It must be the same circuit based in part on art 300.3. If you have 2 circuits in the 2 gang switch box then a neutral from each circuit must be present

 

[George Stolz]

404.2(C) explicitly requires the neutral from the controlled lighting circuit.

 

[jimman]

NC DOI Building Code Council

NC DOI Building Code Council

This is from the December 10, 2012 minutes as listed on NC DOI website. Note addition of item 3.

Item D-24 Request by Robert Privott, NC Home Builders Association, to amend the 2011 NC Electrical Code, Section 404.2 (C). The proposed amendment is as follows:
Section 404.2 (C) Switches Controlling Lighting Loads
(C) Switches Controlling Lighting Loads. For switches controlling lighting loads supplied by a grounded general purpose branch circuit, the grounded circuit conductor for the controlled lighting circuit shall be provided at the switch location.
Exception: the grounded circuit conductor shall be permitted to be omitted from the switch enclosure where either of the following conditions in (1), or (2) or (3) apply:
1. Conductors for switches controlling lighting loads enter the box to a raceway. The raceway shall have sufficient cross sectional area to accommodate the extension of the grounded circuit conductor of the lighting circuit to the switch location whether or not the conductors in the raceway are required to be increased in size to comply with 310.15(B)(2)(a).
2. Cable assemblies for switches controlling lighting loads enter the box through framing cavity that is open at the top of bottom on the same floor level, or through a wall, floor, or ceiling that is unfinished on one side.
3. Residential one- and two-family dwellings.
Motion/Second/Adopted as modified ? This motion was passed unanimously

 

[RustyShackleford]

We join at least one other state in amending 404.2(C). From another forum:

2011 Mass Electrical code

404.2(C). Designate the exception as “Exception No. 1” and insert an additional exception as follows:
Exception No. 2: Where multiple switch locations control the same lighting load in an interior room or space, a grounded conductor of the lighting circuit shall not be required at each such location if one has been provided at one or more switching points that is (are) visible from most areas within the room including all principal entry points.

Where a switch controls a receptacle load or a lighting load that does not serve a habitable room or bathroom, or where automatic control of lighting has been provided or the switch is not within the lit area, a grounded circuit conductor shall not be required.

 

[RustyShackleford]

This is from the December 10, 2012 minutes as listed on NC DOI website. Note addition of item 3.

The proposed amendment is as follows:
Section 404.2 (C) Switches Controlling Lighting Loads
(C) Switches Controlling Lighting Loads. For switches controlling lighting loads supplied by a grounded general purpose branch circuit, the grounded circuit conductor for the controlled lighting circuit shall be provided at the switch location.
Exception: the grounded circuit conductor shall be permitted to be omitted from the switch enclosure where either of the following conditions in (1), or (2) or (3) apply:
1. Conductors for switches controlling lighting loads enter the box to a raceway. The raceway shall have sufficient cross sectional area to accommodate the extension of the grounded circuit conductor of the lighting circuit to the switch location whether or not the conductors in the raceway are required to be increased in size to comply with 310.15(B)(2)(a).
2. Cable assemblies for switches controlling lighting loads enter the box through framing cavity that is open at the top of bottom on the same floor level, or through a wall, floor, or ceiling that is unfinished on one side.
3. Residential one- and two-family dwellings.
Motion/Second/Adopted as modified ? This motion was passed unanimously

So does this mean that, effectively immediately, 404.2(c) no longer applies to those of us doing residential work in the Tarheel State ? Is there an issue of when the permit was pulled relative to the date of this amendment ? How much likelihood is there that local inspectors would be unaware of this amendment, and if so, would simply showing them a printout (of the relevant page from the NC DOI minutes) do the trick ?

 

[John120/240]

This is from the December 10, 2012 minutes as listed on NC DOI website. Note addition of item 3.

Item D-24 Request by Robert Privott, NC Home Builders Association, to amend the 2011 NC Electrical Code, Section 404.2 (C). The proposed amendment is as follows:
Section 404.2 (C) Switches Controlling Lighting Loads
(C) Switches Controlling Lighting Loads. For switches controlling lighting loads supplied by a grounded general purpose branch circuit, the grounded circuit conductor for the controlled lighting circuit shall be provided at the switch location.
Exception: the grounded circuit conductor shall be permitted to be omitted from the switch enclosure where either of the following conditions in (1), or (2) or (3) apply:
1. Conductors for switches controlling lighting loads enter the box to a raceway. The raceway shall have sufficient cross sectional area to accommodate the extension of the grounded circuit conductor of the lighting circuit to the switch location whether or not the conductors in the raceway are required to be increased in size to comply with 310.15(B)(2)(a).
2. Cable assemblies for switches controlling lighting loads enter the box through framing cavity that is open at the top of bottom on the same floor level, or through a wall, floor, or ceiling that is unfinished on one side.
3. Residential one- and two-family dwellings.
Motion/Second/Adopted as modified ? This motion was passed unanimously

So does this mean that, effectively immediately, 404.2(c) no longer applies to those of us doing residential work in the Tarheel State ? Is there an issue of when the permit was pulled relative to the date of this amendment ? How much likelihood is there that local inspectors would be unaware of this amendment, and if so, would simply showing them a printout (of the relevant page from the NC DOI minutes) do the trick ?

Yes it seems to me that you are free to omit the neutral at switch boxes. But why do you want to do that ? Cost ? Wiring to the NEC

minimum is legal but a poor choice IMHO. How much would you save with out a neutral ? Leaving out the neutral at switches

in conduit installations makes more sense than romex installations.

 

[RustyShackleford]

Yes it seems to me that you are free to omit the neutral at switch boxes. But why do you want to do that ?

Only conceivable reason to provide neutral is for occupancy sensor (right ?), and it just doesn't seem to make any sense if switch is not in same area as the light (as per the MA amendment to the provision, mentioned above). I currently have a specific situation where it'd just be awkward to run neutral to both switches in a 3-way setup and it just doesn't seem like there's any good reason. Note it's not always as simple as running 3-wire instead of 2-wire; sometimes 4-wire is required and availability is limited.

I agree with you that NC is overdoing it by completely eliminating 404.2(C) for most residential.