Best solution to install a sense monitor in crowded electrical panel?

Question

I am trying to install a sense device in my electric panel to track my electricity usage. More information here. However, my panel is full, and I am trying to make it work without getting a new panel altogether.

I have sketched out two options, before installing the sense, a section of my electric panel looks like:

First solution is to "piggyback" on an existing double breaker:

Second solution is to install a new quad breaker to group Bedroom1,2 and garage door there and have the sense use the old breaker that was used by the garage door:

My understanding is that solution 1 potentially does not meet the code, and solution 2 is fine but involves buying a new breaker. A better but significantly costlier solution would be to install a new electric panel. Is my analysis correct?

Answer 1

Don’t put this device on anything larger than a 20 amp circuit.

these monitors draw very little power and putting them on a large breaker is asking for problems if and when things go bad.

Use a 15 or 20 amp circuit to power the system then if the worst happens you won’t be rewiring the entire panel.

If your breakers allow 2 wires per breaker great add the monitor directly. If your panel only allows 1 wire per lug get a few inches of the correct sized wire for the breaker 20 amp use #12 or 15 amp use #14 wire a few inches out use a wire nut or some kind of splice device to tie the original conductor your new jumper and the power to the monitor all together. Then put the other end of the new wire to the breaker (a splice in the panel is ok).

If you need voltage sense tap a breaker close to the main lugs.

The reason I said not to use anything larger than a 20 amp is if the power supply fails it would melt the wiring down before tripping the 50 amp bkr, as the wires melt down they usually cross others on the hot or neutral / ground and depending on the failure I have had to replace several panels for aftermarket equipment that went up in flames. Most of these are measuring the current using current transformers (no actual contact to the wires but the meter and transmitter need power)

Your garage door should not be on a 50 amp breaker in any case.

Answer 2

First, the Sense takes a tiny amount of power. It doesn't need a 50A breaker (if it did, it would need a water-cooling system that was quite large!) So it's no problem for the Sense to share breakers with other circuits.

Look at your circuit breakers (possibly pull one out, no need to detach the wire). See if it has markings that indicate it accepts 2 wires on a lug. If so, easy peasy. If not, you'll have to pigtail.

Sense is ETL-listed, so it has official paper installation instructions. Those are the only instructions with legal force (NEC 110.3b) and you must follow them. Any other instructions do not matter. These will tell you a required breaker size. Armed with that, search your breakers.

Now, certain breakers are required to be dedicated circuits. EVSE, and the 20A circuits required for garage, laundry, bathrooms and kitchen. You're not supposed to use those, but I honestly really can't imagine an inspector flagging that - Sense is such a small load.

First choice is a 240V breaker, smaller the better.

Second choice would be any existing multi-wire branch circuits. Those are supposed to be handle-tied already. But if it isn't already a 2-pole "common trip" 240V breaker, it will need to be. Anytime a multi-wire branch circuit supplies both 120V and 240V loads, the breaker must be common-trip (a handle tie is not good enough).

Last choice would be taking 2 simple circuits and turning them into a MWBC, and using those 2 breakers. This will only work if they are NOT GFCI or AFCI breakers, as those don't work with MWBCs.

Answer 3

More information on your breaker box would help, especially a photo with the cover off. Sense needs a double pole breaker to read both 120 +/- legs, and a neutral/ground to monitor incoming and outgoing power. Square D breakers typically allow 2 copper (Cu) wires per breaker. GE breakers only have one. If you can't double-tap properly an acceptable fix is to pigtail the hot wire from the original circuit (under 20amps) to the wire from the Sense, plus a jumper wire that will connect to the breaker, secure with a wire nut. Typically you want a 15 or 20 AMP dual pole breaker. You may be able to room for a new breaker by switching out some of your existing breakers with tandem/slim breakers depending on the brand; that is only if your box can handle more poles or the new total AMPs allowed for the box. To calculate your box capacity look at the label of your panel for the max amperage, the max number of poles, and divide by 10. eg: 150 (Amp Max Box) x 24 (Poles/Breakers) / 10 = 360. Take that number and subtract the total of all the 24 breaker's AMP ratings to see if the box will be at or under that capacity and not over. Hope this helps get your Sense Energy Monitor connected in your house for some energy savings. For more info on pigtailing see this video: https://youtu.be/aVbY5VSQLi0

Answer 4

trying to make sense of your sense pull out a 20 amp 240 volt circuit out of the panel, install it in a junction box beside panel feed that junction box from that breaker, parallel it with your sense voltage leads using the proper connectors. nipple out of mains section of your panel using a proper bushing and sized large enough for sense connector to fit through now remember when you are working in the main panel and unless you get them to turn the water off at the dam site it is going to be hot/live. be very very care full when applying CT's monitor should not be installed in panel, always exterior to.. also does not appear to be approved for canada