Is a neutral wire required in a metal switch box?

[Danny89]

Situation is a single circuit 120v. Simple single pole toggle switch. My journeyman said if it's in pipe no neutral is needed in the device / switch box. If it is in MC cable then a neutral must be in the device switch box.

Is there a code reference for this. I thought I remembered reading in the 2017 code a neutral must be in the switch/ device box no matter if it is in pipe or EMT...

Thanks in advance

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[FionaZuppa]

N or EGC you talking about?

For some switched items you can bring only the switch leg to the switch (w/ egc). So like "romex" 14/2 that comes down from a light, you hook white & black & egc to the switch yoke. Hence no need to cap the N for passthrough.

Can you add some clarity to your Q?

 

[tom baker]

Its all about adding a motion sensor later. Most motion sensors work Hot to Ground, putting about .05 mA on the EGC, in a large building this can add up and present a shock hazard. Please see 404.2 C and then 404.22

 

[tom baker]

N or EGC you talking about?

For some switched items you can bring only the switch leg to the switch (w/ egc). So like "romex" 14/2 that comes down from a light, you hook white & black & egc to the switch yoke. Hence no need to cap the N for passthrough.

Can you add some clarity to your Q?

In some cases with romex the neutral must be available even with a switch loop

 

[McLintock]

I put the neutral in every box I do, lot less headache in the future. The cost is a few cents more, so do you really save money not running a neutral?

My boss ran a 14/2 for a 4-way switch, so had to use a neutral off another circuit, he did not tell me, got shocked yelled at him and told him not to do that again, spend a little more on 14/3 and make everything simple and safe


“ shoot low boys their riding shetland ponies”

 

[Dennis Alwon]

I put the neutral in every box I do, lot less headache in the future. The cost is a few cents more, so do you really save money not running a neutral?

My boss ran a 14/2 for a 4-way switch, so had to use a neutral off another circuit, he did not tell me, got shocked yelled at him and told him not to do that again, spend a little more on 14/3 and make everything simple and safe


“ shoot low boys their riding shetland ponies”

Why bother running the neutral if it is not compliant. Connecting to a different circuit is not compliant, IMO

 

[electrofelon]

No one has really directly answered the OP. Yes it is now code required to have the circuit neutral/grounded conductor available in the switch box. There are some exceptions such as if the wiring method is conduit so it can be added later, or for switches controlling receptacles. See 404.2

 

[tom baker]

No one has really directly answered the OP. Yes it is now code required to have the circuit neutral/grounded conductor available in the switch box. There are some exceptions such as if the wiring method is conduit so it can be added later, or for switches controlling receptacles. See 404.2

I answered with the code section

 

[electrofelon]

I answered with the code section

Sorry, don't know how I missed that.

 

[Jon456]

Its all about adding a motion sensor later. Most motion sensors work Hot to Ground, putting about .05 mA on the EGC, in a large building this can add up and present a shock hazard. Please see 404.2 C and then 404.22

I would add that it's not just for motion sensor switches. Most modern "smart" switches and timer switches require a neutral because they use a constant trickle current to power the switch's internal electronics.

ETA: I know that you know that, Tom, but I just wanted to give a more complete reason for any readers wondering why code now requires a neutral in switch boxes.

 

[480sparky]

I would add that it's not just for motion sensor switches. Most modern "smart" switches and timer switches require a neutral because they use a constant trickle current to power the switch's internal electronics.

ETA: I know that you know that, Tom, but I just wanted to give a more complete reason for any readers wondering why code now requires a neutral in switch boxes.

Yes... this is exactly the reason the neutral requirement was added to the Code. Too many installers of these electronic switches were bootlegging onto the grounding conductor. Yes, it works, but now you're got current flowing on the ground all the time.

 

[tom baker]

Yes... this is exactly the reason the neutral requirement was added to the Code. Too many installers of these electronic switches were bootlegging onto the grounding conductor. Yes, it works, but now you're got current flowing on the ground all the time.

And the electronic switches were designed to connect to the EGC, which is why 404.22 was added, this section took effect Jan 1, 2020, to prevent introducing current on the EGC.

 

[FionaZuppa]

And the electronic switches were designed to connect to the EGC, which is why 404.22 was added, this section took effect Jan 1, 2020, to prevent introducing current on the EGC.

404.22 makes back ref to 404.2(C)

But what is meant by this exception 404.2(C)Ex4 ?
Doesnt the electronic doodad control the switching by "automated" means, like a room occupancy light controlled by motion sensor in the switch?

And then 404.2(C) says for some types of installs, the grounded CCC is not required at every switch location.

 

[ActionDave]

404.22 makes back ref to 404.2(C)

But what is meant by this exception 404.2(C)Ex4 ?
Doesnt the electronic doodad control the switching by "automated" means, like a room occupancy light controlled by motion sensor in the switch?

That's not what the section is talking about. At the far end of the spectrum there are entire buildings where the lighting is controlled by automated systems and the controls are all networked back to a central control room. Even in places not that extreme it is not uncommon for there to be rooms where there is not anything that resembles a traditional light switch anywhere.

And then 404.2(C) says for some types of installs, the grounded CCC is not required at every switch location.

Am I ever going to need a neutral for a motion sensor inside the door switch that turns on a light when I open my closet?

 

[kwired]

Please also note the title of 404.2(C) "Switches controlling lighting loads".

This rule applies to circuits that utilize a grounded conductor, which most general use lighting circuits do, but say it were a 240 or 480 volt circuit that did not utilize a grounded conductor you wouldn't need one there either.

Also if wiring method is raceway you don't necessarily need to install the grounded conductor, but somewhere they did throw in that you must still have room in the raceway to add one if ever needed, that rule was not there the first code cycle that had this grounded conductor in the switch box requirement but got added the next cycle.