Flex sensor

I would like to monitor all the electricity used on a breaker. This breaker is on a separate panel from my main panel that the Sense monitor is on. Panel is about 40 feet away from the main panel. So how would I do this? Could I hook up a flex sensor and have a run that long to the breaker in the remote panel?

Yes, Sense offers extension cables in up to 40’ lengths. But some posters here have also created their own up to about 100’.

Thanks. Even 40 feet might be cutting it close. How do you make an extension cable? What type of connectors are they?

Here’s a DIY example.

1 Like

Thanks. So what kind of connector does it have?

I’m still hoping to see a WiFi enabled CT’s that will integrate with sense.

I totally agree about Wi-Fi. That makes perfect sense.

But in the meantime, regarding the extension cables, can you chain them together?

If you make your own, you would just use 18-22awg twisted pair wire. I’m not sure what distance you would have to start worry about interference but STP (shielded twisted pair) would help. It doesn’t look like the wire that are on the CTs are shielded, I’m not sure about the sense ones from their store.

Cat5e wire is normally 24awg
Cat6 and Cat7 wire is 23awg and you won’t get into the 22awg stuff until you hit Cat8. Should be fairly easy to find twisted 2 pair 18awg wire on the internet but the ones sold by sense are probably close to that price point

You can also chain 2 of the 25ft tigger them together. At some distance your going to start loosing accuracy.

So my electrician opened up my electrical panel to hook up the flex sensor to my Sense unit. The sense unit wasn’t attached to anything and fell a couple of feet and the cable connector going to the current clamps broke. The connector is very fragile apparently. How do I replace it? I don’t see a replacement on your website. It appears that it’s the same as a Flex Sensor, is it?

Flex is not the same as the main sensor. It is calibrated differently. You probably want to contact support@sense.com.

KevinD, thanks for the informative answer to the question of the OP. Before I cut into my Sense extension cable to splice it to some twisted pair wire to make a60 foot extension, can you advise how many wires are really needed in the original Sense cable? I see CAT wire has 4 pairs. Does Sense need all 4 of these pairs?

Each CT needs 2 wires (a single twisted pair). Not sure if the extension cable needs a shield wired to ground.

Thank you KevinD. Somehow my computer asked the question twice.

KevinD - I’m expecting a Sense extension cable today so don’t yet know what the pinout looks like for the plug and socket. Without pulling the CTs off my panel, is there a way to know which pair of wires (or pins in the plug) will belong to which CT? I see the possibility of cross wiring each CT to the wrong wires of the CAT5e cable that I will splice into the cut Sense extension cable.
Any advice please?

If you have flex cables coming, then you should have a separate sheath for each CT, like in these photos.

Sorry I called you KevinD - should be Kevin1, oops. I hadn’t seen that thread, so read it just now. I still am not clear on an answer. I know that 2 CT cables connect to one plug. Therefore there are 4 wires at the plug pins. Is there a way to now which pair of pins belong to which CT? When I get things apart perhaps I can use an ohmmeter to determine each set of wire pairs. Or, with the CTs clamped on the solar feed lines, use a volt meter to find the correct pairs. Should be about 1 volt - not sure if AC or DC at that point. Experiment.

Yes, two CTs to a plug - but I’m assuming you will:

  • Cut the two sheaths / bundles between the plug and the CTs to extend.
  • Once you cut the sheathes there will only be ONE wire pair within
  • You can extend each pair separately as long as you maintain the color conventions on each end of the CAT wires.

Aah, got it Kevin1. I see now how he did it. I intend to NOT cut the cable between the CTs and their common plug. By buying an extra Sense extension cable I will have a new plug and new socket. Therefore I will cut the CAT5e and splice it between those two ends. If I ever have to reverse this idea, they will still be original.
When I get a wiring diagram together I will post it here for the next questioner.
Thanks.

Well, the extension is in and I am getting readings on both mains and solar.

Finding the correct pins from the two CTs at the single 4 pin plug was easier than I expected. An ammeter shows each CT has about 7 ohms resistance.

Thanks Kevin1 now I know how to post a PNG or JPG file here.

2 Likes

Post a photo by using the the little icon circled in red, at the top text entry box.

1 Like