Code (NEC) question

If the thing in the picture is not a listed device (per the NEC meaning of "listed") then you cannot use it as part of the facility wiring and consider it NEC compliant. Volume computation doesn't come into it if the device is non-compliant.

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.

Ed

The devices are listed. I deliberately avoided the temptation to design my own interface to the signal lead.

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.

I figured a mains powered lamp, visible through the Jbox, wouldn't raise any eyebrows "electrically".

But, then have to consider how *that* is interpreted in volume calculations.

Yes, because it occupies volume that is thus made unavailable for any other use. In the extreme, there would be no volume available at all fro anything else.

Joe

D'uh... but, it doesn't tell me if it counts as the same 2 volume units as other "devices" or if it has some other burden rate. There is nothing on the device or the documentation to that effect.

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.

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 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.

Well, if willing, your local AHJ can assist you. The bottom line with "code compliance" is getting the local AHJ's approval.

Ed

I'm not worried about the conductors. I've done the calculations many times for different installations.

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.

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).

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.

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"

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. 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 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.

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".

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 lights needed.

Ed

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 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.

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!).

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.

"This module should be installed in a UL listed junction box. All connections should be made by a qualified electrician in accordance with the requirements of the national electric code and/or any other local codes having jurisdiction in your area."

Says a lot of nothing.

"volumne units"? I was under the impression that boxes were measured in cubic inches, surely you can determine this empirically.

Here's what you are up against: The AHJ may look at the "thing" and see that one of the conductors thjat is part of the "thing" is larger than any conductor entering the box. In the absence of any "official documentation" (ie NEC, listing testing lab's analysis) he/she may take the position that, regardless of the current electrical installation plan, at some time in the future a larger conductor may be used to connect to the larger conductor that is part of the "thing". As you have said, you are not in a position to support the position that "document XYZ" specifies the volume to be used in the computation for the thing.

I say this because you continually request that information in this conversation between you and me. I have tried, and failed, to get you to realize that NO ONE can give you that here with some unknown device being discussed. I've tried, and failed, to deal with this in the general sense with the device being a secret.

Ok, that said, please reconsider your approach to posting this. The question you should ask: "Per the NEC what is the volume to be used in computing junction box size for device P/N XYZ manufactured by ABC company when installing it in a junction box?"

You gave no specifics. I tried to answer the non-specific issue with general information as if I was the AHJ involved. Sorry, but that's the best I can offer.

Ed

They are listeds part. They are available in large quantities from any number of outlets. They are produced by leading manufacturers in that field (e.g., smoke detector companies) as "approved" interfaces to their own proprietary signaling systems.

The "shared interface" doesn't appear to be standardized as each manufacturer wants ONLY devices of their own make to intercommunicate with other (their) such devices.

I went this route rather than analyzing the interface and designing something that could snoop it /because the devices already exist and are already listed/. I'm not "breaking new ground".

Yet, they expect a "licensed electrician" to be able to intuit how the NEC (and local code) applies.

My question is: "Dear licensed electrician; when presented with THIS device and THIS paperwork and THIS listing, how do you interpret that in the context of the NEC and any other local codes? Please don't just wire it in place as the building may not be certified for habitation if you just 'wing it'"

Posting here, I was hoping that someone might have a more general understanding of how such questions would be resolved, beyond just asking an electrician and wondering how much of his response is authoritative vs. just bluster.

There's nothing "secret" about them. Manufacturers of "interconnected alarms" seem to offer them as a standard product to allow access to said "signaling" information.

In commercial settings, there are other approaches/devices.

I asked if it could be considered as a "device" in the same sense that a switch or receptacle would be considered. This acknowledges that it's *volume* isn't the important issue (I could measure that with a set of calipers) but, rather how the Code would view the item.

Note that it doesn't have a typical shape -- what are the physical extents of the device?

Note that I also asked how to handle using the isolated side in a low voltage application given that it isn't practical to ENSURE spacing inside a typical box of wire. And, proposed a solution that avoided the low voltage issue by using the device solely as an interface and manipulating another line-powered circuit.

This fits with the *typical* usage of such a device: "I want to sound an annunciator when the alarms are triggered" (except my annuniciator is another electronic device)

I can audibly couple to a detector but that's a bit more difficult to convince folks that such detection is "reliable".

Thanks. I'll escalate it to the architect and let him sort out how to address it with the regulatory authorities. He (via the developer) has much more at $take (and more levers to manipulate). Much easier than trying to explain how some random piece of electronics is interacting with a signal that isn't supposed to be "touched".