From: blockedofcourse@foo.invalid   
      
   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.   
      
   > Personally - but based on the picture alone - I doubt the thing   
   > can be installed in a junction box in facility wiring in   
   > compliance with NEC or local electrical code.  Perhaps it could   
   > be installed in some kind of control panel with whatever indicator   
      
   [continued in next message]   
      
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