Power Monitor Modifications
pjpfeiff
| Posted in General Questions on
I have power monitor that I’d like to have totally enclosed in the electrical panel. Currently it has two things that plug into a receptacle–a 12 VAC adapter for monitoring voltage and a 5 VDC power supply via USB-C. Are there any products that could make those conversions from an empty breaker in a code-approved manner?
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Replies
I don't think there is a code compliant way.
The way these are always mounted are in an enclosure with a small conduit run to the main panel. This is compliant, pretty easy to do, cost not much more and make any servicing down the road a breeze.
Thanks, that's pretty much what my friend who created the monitor told me. Simple jobs often end up taking me a lot longer than seems reasonable, and I may be doing this at a few different panels, so I like to make it as simple as possible. But not having to open the panel to access the monitor will certainly be a plus.
+1 for installing all this stuff in a seperate enclosure outside the electrical panel. I would look into a "hoffman box" (Hoffman is a manufacturer, there are other options), which you can get in large sizes like 8 x 8 x 4 inches. Commercial electrical supply houses tend to stock these. Install a receptacle sideways on when edge of the box ("sideways" means facing towards the interior of the box, not towards the front). Link the box to the electrical panel with a short piece of conduit, typically called a "nipple". You can now put all your fancy monitoring gizmos in that box, powered from the receptacle in there, and run the monitoring wires back to the panel through the short piece of conduit.
As far as I know, there is no code compliant way to use plug-in power supplies within an electrical panel, and I wouldn't try to do that even if there was a code compliant way to do it.
Bill
Thanks. I like the idea of the receptacle attached to the edge. Do any of these hoffman boxes come with a mounting point for a junction box, or do you have to cut/drill your own? Or...do you put a handy-box inside the hoffman box?
For what it's worth I wasn't looking for a plug-in power supply to got inside the panel, but a hard-wired one. The Emporia Vue Gen 2 (which I do not have) apparently goes inside the panel and is wired directly to two empty breakers. I'm assuming it steps down the voltage in the unit itself.
Those boxes sometimes have knockouts, but otherwise you drill all your own holes. You can get back plates for some of them though, which provide a mounting plate that attaches to the back of the box with four nuts, so you can mount your gizmos to the plate, then mount the plate into the box.
I would use a handybox and handy box duplex cover for a receptacle in the box.
For a hard-wired power supply, I'd look at one of the DIN rail mountable power supplies for industrial controls. B and B Electronics has a lot of that sort of thing.
Bill
Thanks. I forgot to mention that the monitor communicates via wi-fi...should I be looking for plastic enclosures? Or, would it be acceptable (and effective) to cut some holes in a metal enclosure to allow wi-fi through?
Or actually, as long as the receptacle is in an appropriate box, do I even need an enclosure? Could I install everything in the wall and put an access panel over it? I'd prefer to have an enclosure, but going without should provide sufficient wi-fi signal.
Bill --
I know a little about electrical, and I'm always trying to learn more. My understanding is that a panel is treated like a junction box, anything that is allowed in a junction box is allowed inside a panel. Is that not correct? If so what's the division?
Thanks
You're not supposed to use the electrical panel as a junction box, i.e. any wire in that panel is supposed to go to something in the panel, not through it to something else.
Using a "junction box" the way I describe though is more like a small controls cabinet, and not really a junction box anymore. The box becomes the enclosure for the controls, so it's not really considered a "junction box" when used this way -- it's just easier (and a whole lot cheaper!) to buy a steel cabinet sold as a large "junction box", and then to use it as a controls cabinet. This sort of thing is done all the time commerically. If you step up to an "oil tight" box (still from Hoffman or similar), you get something that looks more like a cabinet though, with a real hinged door. Price is a lot higher for those though, and you don't really need a gasketed and hinged cover for something like this.
Bill
OK, I see the distinction. It seems not uncommon for there to be junctions in the panel -- a conductor that isn't long enough is extended using a wire nut.
Or should that not be? Should they have put an actual junction box and extended the cable to the junction box?
You're OK extending a too-short wire with a wirenut inside the electrical panel. That's OK, because you're extending a wire that is entering the panel with the intention of terminating on something within the panel (like a circuit breaker). What you're generally not supposed to do is to run wires into the panel, then pass them back out again on the way to something else. There are some exceptions to this, but it's generally considered to be bad practice. Wires that go into an electrical panel should terminate within that panel. If you have wires that need to pass through to somewhere other than that electrical panel, then you should use a junction box or trough outside of the electrical panel to make those "pass through" connections.
Bill
If I might make a suggestion and say you should get a different power monitor that hard wires directly into a breaker, like the sense monitor. The amount of work the alternative is does not make sense (pun intended) in my mind.
For one thing I want to monitor specific circuits. It looks like the Emporia Vue Gen 2 would fit the bill pretty well, but I would really like long term access to the 1-second data because I'm crazy. In any case, the monitor I have was created by a friend of mine, do that also makes me partial to it.
I believe you can flash the Vue Gen 2 with open-source monitoring software so you can keep the data on a local system.