[Originally posted to energy because I misread the response from find-support] I have a device which has a TT-30 receptacle, an extension cord with a TT-30 plug on one end and a L14-30 receptacle on the other, and an L14-30 plug in a metal box. I’m looking for a smart plug that I can stick on either side of that extension cord to give me an idea of how much power is passing through the cord at any given time, with the eventual intent of making a dashboard graph showing power usage over time and cumulative power usage. Are there any smart plugs that aren’t boring old 110VAC? Thanks in advance!
#Looking to find a smart plug for L14-30 or TT-30
silver sentinel
cunning sedge
[Originally posted to energy because I misread the response from find-support] I...
i imagine the answer is no. you are likely better off using a ct clamp style setup. however you are also dealing with split phases here then this might be a bit complicated and also depends on your load configuration.
what is your actual use case? what is the load? how is stuff wired?
silver sentinel
The device is an Anker F2000, which only has a single phase, not a split phase. The "other side" is a power panel with multiple circuits that powers my home office / ham shack. The Anker has some telemetry but it doesn't accurately report how much power is being drawn.
cunning sedge
The device is an Anker F2000, which only has a single phase, not a split phase. ...
ah right i got you the l14-30 has split phase in theory but a tt-30 only has the ends for 240 power.
you should look at a ct clamp solution but you need to clamp only the live connection. you could make a box that wires inline on your extension lead that would allow you to power something like the shelly-em and clamp the live cable. or find a place to do this "upstream" potentially in the electrical box.
but in any case, your most likely not going to get "smart plug" style device for a 30A connection. and tbh if one does exist i probably wouldn't trust it
silver sentinel
From what I've been reading, the clamp solution requires cutting the extension cord and putting the clamp only on one of the 3-4 wires in the cord, right?
cunning sedge
From what I've been reading, the clamp solution requires cutting the extension c...
yes it needs to go over only 1 leg of the AC signal
silver sentinel
I think I've done that with a Fluke meter, but I don't know of any long-term solution with like Bluetooth or something, what vendors would offer something like that?
cunning sedge
a shelly-em is a wifi option
silver sentinel
Ah, found something on Shelly's website, clamp looks right but bare terminals for power looks like an accident waiting to happen for something outside a box
cunning sedge
get a plastic electrical box to put everything into
silver sentinel
Worst case I could probably 3d print something. That does look like it'd work. The 50A would be fine since the setup maxes out at 30A, right?
cunning sedge
yeah
silver sentinel
From here I should be able to figure something out. Thank you for the help!
cunning sedge
forgive the crude diagram but put stuff in a box. have the live/neutral into terminal blocks or something. split off those blocks to power the shelly then put the clamp over 1 leg (usually the live)
just go get a standard electrical wiring box to put stuff inside
there will be a ground/eath wire too obviously which you just connect together the sides
cunning sedge
From here I should be able to figure something out. Thank you for the help!
also please be careful. mains power can and will kill you.
silver sentinel
That's an interesting idea for boxing it up -- I was going to keep the Shelly base unit in a box, with clamp cable and power cable coming out of the box -- then remove the exterior wrapper of the extension cord to expose the bit where the clamp goes.
With your approach, I'd almost rather the box have a plug and socket on either side.
cunning sedge
so its hard to cut out sleving off without nicking internal cables and would also end up leaving you with only single insulated wires. putting it in a plastic box maintains the protection.
cunning sedge
With your approach, I'd almost rather the box have a plug and socket on either s...
yup, you could get a box and plug a socket on either side of the right type. just be sure that theres no way of wiring it so you have a death cable with exposed live pins
silver sentinel
Actually, hmm.
There exists a metal box with the plug in it already
The next time I take down the power, I'll open the box and see if there's room in it.
The "an L14-30 plug in a metal box" from the original description.
The metal won't be as kind as plastic to the WiFi but I think that's less of a concern.
cunning sedge
its quite alot to put in a plug backbox, plus if its metal you have to careful with the wiring to not run the risk of the box becoming live
silver sentinel
The existing box has a little grommet on the side the kind of thing that conduit would be attached to if it were wired through there
cunning sedge
The existing box has a little grommet on the side the kind of thing that conduit...
you could maybe add another box to the wall next to it for the shelly. that way you could wire through the gromet to get access to the 240 to power the shelly and also to clamp the live signal
silver sentinel
That way only the clamp would be in the existing box around the existing live connection
cunning sedge
you still need to power the shelly
which should be powered from the same line that your reading
silver sentinel
Yes
Data cable from clamp and power lines off the 240v would pass through the grommet to the new plastic box holding the Shelly
cunning sedge
yes
silver sentinel
A lot safer than the other idea of mine, thank you.