From: ehsjr@verizon.net   
      
   On 2/9/2026 12:17 AM, Don Y wrote:   
   > On 2/8/2026 8:32 PM, ehsjr wrote:   
   >> On 2/8/2026 7:28 PM, Don Y wrote:   
   >>> On 2/8/2026 3:11 PM, ehsjr wrote:   
   >>>>> But, that still doesn't tell me if it is considered as a "device"   
   >>>>> in the same sense that a light switch, receptacle, etc. would be   
   >>>>> in volume calculations.   
   >>>>   
   >>>> For volume calculations you need to look at NEC section 314.16   
   >>>> I can't tell for sure how many conductors are in the picture,   
   >>>> nor can I tell their size or the number of conductors of conductors   
   >>>> entering the box.   
   >>>   
   >>> I'm not worried about the conductors.   
   >> The box size must be computed based on the number of conductors   
   >> entering the box, among other things.  Since the picture shows   
   >> many conductors of unknown size there is no way readers of your   
   >> post can give you the answer you seek. We can't say "the minimum   
   >> box size for the thing (whatever it is) is X"   
   >   
   > I don't need to know the minimum box size.  What I need to   
   > know is how much the "device" ("thing") contributes to the   
   > volume calculation.  Can I reliably claim that it counts   
   > *as* a regular "device" -- 2 volume units?   
   >   
   > As I've said, I'm not worried about the conductors.  I've   
   > done these calculations for "normal 'devices'" since I was   
   > a child (I had two uncles who were master electricians   
   > so would play tag-along to job sites, each of them wanting   
   > to "show me things")   
   >   
   > The code claims that conductors originating and terminating   
   > in the box "don't count" (except grounding conductors).   
   >   
   > The conductors *entering* and exiting (passing through) the   
   > box are easy to address.   
   >   
   >> Next: from the picture it does not appear this is a yoke   
   >> connected device. If it is not a yoked device, then the   
   >> rule of 2 conductor volumes does not necessarily apply.   
   >   
   > *Something* will address it.  It's too much volume to   
   > just assume "it doesn't count".  From wire volume units   
   > *alone*, I likely could claim it could fit in a 6 cu in   
   > box -- despite the fact that it wouldn't actually FIT in   
   > such a small box!   
   >   
   >> For those unfamiliar with the code: That rule says that   
   >> for each yoked device installed at the box you must add   
   >> two conductor volumes for the largest sized conductor entering   
   >> the box.   
   >>   
   >>> I've done the calculations   
   >>> many times for different installations.   
   >>>   
   >>> *BUT*, I always knew that a switch, receptacle, etc. counted as   
   >>> a "device" -- 2 volume units.   
   >>>   
   >>> I don't see anything in the code or marked on the device (or its   
   >>> documentation) that would clearly state how this "thing" (avoiding   
   >>> the use of the term "device") should be handled in those calculations.   
   >>>   
   >>>> Whether compliant for installation where planned or not would be   
   >>>> determined by the AHJ during the electrical plan review phase.  Not   
   >>>> all jurisdictions follow the NEC. (For exanmple, NYC has its own   
   >>>> code) There can be local rules more stringent than the NEC. That   
   >>>> said for NEC compliance section 314.16 applies.   
   >>>>   
   >>>>>> If you're wondering about the UL224 marking, it's   
   >>>>>> for the heatshrink, not whatever is inside.   
   >>>>>>   
   >>>>>> Question 2:  dunno.   
   >>>>>>   
   >>>>>> Question 3:  Either get it listed, operate it under   
   >>>>>> "engineering supervision" acceptable to the AHJ   
   >>>>>> (electrical inspector at the usage location), or   
   >>>>>> build it into an appliance that is not part of the   
   >>>>>> facility wiring.  I'm sure you don't want any of   
   >>>>>> that; I don't know how else to do it. Sorry.   
   >>>>>   
   >>>>> I figured a mains powered lamp, visible through the   
   >>>>> Jbox, wouldn't raise any eyebrows "electrically".   
   >>>>   
   >>>> If you modify the box to make the lamp visible, that's   
   >>>> a violation.  The NEC says you must follow manufacturers   
   >>>> instructions for installation and use of equipment.   
   >>>> There may be some kind of listed "indicator" junction box   
   >>>> that suits your specific needs - I dunno.   
   >>>   
   >>> Install a listed "night light" and monitor the light   
   >>> output.  (we have several of these wired in hallways and   
   >>> bathrooms)   
   >>>   
   >>> But, then you have to explain "why is that light, there?"   
   >>> (forget the inspector; imagine the property owner asking)   
   >>>   
   >>> AFAICT, these "things" are primarily used to isolate   
   >>> a control signal to an external annunciator or actuator.   
   >>> E.g., switch the mains to a klaxon in the event of   
   >>> an "event".  Or, *remove* power from an electric door   
   >>> clamp (so fire doors close under spring power).   
   >>>   
   >>>>> But, then have to consider how *that* is interpreted   
   >>>>> in volume calculations.   
   >>>>   
   >>>> Well, if willing, your local AHJ can assist you.  The   
   >>>> bottom line with "code compliance" is getting the local   
   >>>> AHJ's approval.   
   >>>   
   >>> I'm not worried about *my* AHJ but, rather, someone who wants to   
   >>> install a system in Wyoming, Boston, Los Angeles, etc.  If I can't   
   >>> confidently argue for a particular interpretation of the Code, then   
   >>> I can be sure the local "inspector" will resort to whatever "whim"   
   >>> suits him (given this is likely NOT the sort of thing he would have   
   >>> encountered -- and, of course, their word is Gospel!).  I need to   
   >>> be able to comfortably describe the requirements to an architect   
   >>> and not have him balk at them so he can defend them to the local   
   >>> authority.   
   >>   
   >> I was afraid of that. Ok, apparently getting help from the   
   >> AHJ in your location is a non-starter.  He/she could have   
   >> steered you to the UL white book - if UL listed - or   
   >> documentation from whichever listing agency it is.   
   >   
   > My experiences with the local inspectors leaves a lot to   
   > be desired.  I learned, long ago, not to get into an argument   
   > with them as they'll just dig in their heels and "can't"   
   > be proven wrong (legally!).   
   >   
   > [I recall asking the fire department for information on   
   > siting smoke detectors and they looked at me like they had   
   > never heard of such things!]   
   >   
   >> You said it is listed so there should be manufacturer's   
   >> instructions for installation/use, but apparently that's   
   >> not the case with this "thing".   
   >   
   > The instructions pertain only to the functionality of the device,   
   > not the code requirements that it must meet.  E.g., here's   
   > what the wire colors mean, here's how to wire it for a load   
   > to be activated during alarm events, here's how to wire it for   
   > a load that should be *dropped* during alarm events, etc.   
   >   
   > Beyond that, the load carrying capacity of the contacts   
   > and a constraint not to exceed 1000 ft of signaling wire   
   > in the net.   
   >   
   > And, a precaution not to power the device from an inverter.   
   >   
      
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