US Mounting Outside Panel Question


Curious on how others have mounted their IoTaWatt units outside of the panel and are the CT connectors with the 1.5m (~5’) extended cables (from @overeasy) enough to reach outside of the panel from nearly all circuits without issue?

I have seen a YouTube video showing a small conduit on the side of the panel leading to another plastic box for the unit to sit in; with power. I’m wondering if it is better to mount the external box below the panel (if able) so that all the CT wires will drop to the bottom of the panel having more equal amounts of length when they come together. So, the mains up top would be the farthest reach to the bottom. I just assume that putting the external conduit on one side, the CTs for circuits on the other side need to wrap around before getting access to the conduit. Thoughts?

I see two options of mounting the external unit either right or left of the panel, or bottom of the panel; as the mains are at the top. I’m wondering if the ~5ft of cable allow reaching the device whether mounted on side or bottom of the panel.

Something like the dotted section at the bottom of the main panel:


I have seen some commentary on the National Electric Code that suggests a requirement to prevent casual access to low voltage wires that come from a high voltage panel. Once again, electricians know the local applicability and interpretation of the prevailing codes. I think the conduit and plastic box is intended to satisfy that requirement.

I’ve located the IoTaWatt both at the bottom and on the side. The biggest problem that I have is how to neatly organize the extra CT cable length. I don’t think side mount will sell you short on the far side, but it is a lot of wire to route around the inside of the box. Mine is at the bottom.


Thanks @overeasy as usual for the feedback and I was thinking more the bottom just fro the natural flow of gravity to help with cable organization. No issues with the ~5’ cords from the top mains to the bottom using a short conduit and box deployment? I think that is the way I’m headed and will just tie up the extra lengths in the sub box to keep things clean in the panel as you said.


I placed mine above the breaker panel. I attached a small piece of 3/4in plywood above my main panel and ran the sensor cables down through a punchout hole in the top of the panel. I organized the wires by using cable tie mounts every 12 inches. I looped the excess off to the side.


It’s going to depend a lot on your paper and how big it is. I have a plastic electrical junction box below my breaker panel. I have multiple blue Smurf tubes connecting it to the panel. Most of my CTs have 2m cables and they are more than long enough. 1.5m cables are just long enough for most breakers but don’t leave a lot of maneuvering room.


Wow, I would not have ever thought of mounting above as most mains come in from there. Interesting. I will also use cable ties to ensure a clean and out of the way install. Sounds almost like a professional job. Nice.


Thanks for the input @frogmore. Did you put extenders on as many of the CTs I have seen from China have 1m (~3.2’) cables and the ones that @overeasy is offering have some extra over the OEM at 1.5 (~5’). Are you getting cables from a supplier who provides you with 2m (~6.5’) cables on the CTs?


My low voltage box needed to be quite a bit below the circuit breaker box, which is why 1.5m is short of some breakers. The best way to tell is get some string and experiment with what length works. I would expect for a normal sized, ie not a large commercial 3-phase panel, the 1.5m cable would be fine. I bought a Brultech ECM-1240 and a bunch of micro 40 CTs many years ago. The company still exists, but they are not very open and the software has not evolved much in the last decade. I like the openess and responsiveness of @overeasy much better.


I’m with you here @frogmore. I want something that is supported and the more plug-and-play the better. It will be installed in a residential panel and I think going down it the way for me to keep things clean.