Looking for an energy monitor that does not require a plug or breaker on reference voltage of same phase as the HVAC circuit I’m trying to monitor.
Background. I have a 1970’s house in US that used to be all Electric, and as such, I have split service coming into my house, 1 set of mains for HVAC system, and 1 set of mains for my Electrical Panel. Both are monitored by a single Electric meter from the utility company. The mains for HVAC go to a 125A breaker in the garage, then goes straight to a 3 Gang load center in the basement next to the HVAC equipment. There are 0 110V outlets that are tied to the HVAC circuits/ phases.
I would like to monitor the power usage of my Geothermal HVAC system, but I cannot find any type of CT clamp monitor that does not require a reference voltage from the same circuit/ phases as what is being measured/ monitored. I bought an Aeotec Gen 5 energy monitor and could not get that to work on the load center next to HVAC, but it works fine on my basement subpanel with an outlet on the reference circuit.
You are asking a question that scares me.
I think the answer is basic and obvious.
This tells me that before you are tapping into 240 mains circuits, you should get an electrician on site to help with this so you don’t get injured.
No one here can see or check what your home wiring is. The best you will get is guesses, and you have no idea if the person ‘helping’ has any idea or not.
Keep in mind if you know what you are doing, I have no problem helping. But when you clearly do not know anything about the wiring you are looking at then PLEASE get help from someone that does.
Disclaimer
DANGER OF ELECTROCUTION
If your device connects to mains electricity (AC power) there is danger of electrocution if not installed properly. If you don’t know how to install it, please call an electrician.
Beware: certain countries prohibit installation without a licensed electrician present
Remember: SAFETY FIRST. It is not worth the risk to yourself, your family and your home if you don’t know exactly what you are doing. Never tinker or try to flash a device using the serial programming interface while it is connected to MAINS ELECTRICITY (AC power).
Hello, appreciate the caution, and well understood. My neighbor is a commercial electrician, and will be helping me on install if I can find suitable hardware for this situation.
I can install a device like the Aeotec gen 5 on either the main panel for the house or the sub panel for the house, because there are outlets available that are on the same circuit to provide the reference voltage. The problem is that for the HVAC supply to the house, there are no 110 V outlets or 110V breakers anywhere in the circuit.
When I previously tried to use the Aeotec on the loadcenter input to the load center, I was not able to get any readings because any available outlets were coming from the other feed to the house, not the HVAC feed, so my understanding is that if it is not on the same leg, it will not read appropriately.
I don’t want to drop another $100 on hardware if there is not a clear path that it will work. Or the additional cost to add an outlet from the load center to be able to use for the energy monitoring.
OK, so you have a helper. Good.
Run this by them, but in my opinion you want the voltage reference as close as possible to the current measurement, so you tie the voltage reference inside the box to hot-neutral or hot-hot (240) if the device is rated for that inside the box where that wire is hooked up. I suggest adding an inline fuse as well. The voltage depends on the device and what the clamp is monitoring.
Remember I don’t have hands on for your system, have someone help that does and that knows, but referencing from an external outlet might mean you are voltage referencing from a different phase than the current measurement. Also there is a possibility of an induced voltage in a CT plug so having that voltage reference removable can be a bad thing.
DANGER OF ELECTROCUTION 