Author Topic: Adding a second MTU to monitor a single circuit  (Read 2840 times)

gcw1957

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Adding a second MTU to monitor a single circuit
« on: March 08, 2011, 04:20:55 AM »
I purchased the 5000-C with an additional MTU.  I wanted the second MTU to monitor single circuits that would be too complicated to footprint.  In particular, I have a new water heater that uses Heat Pump Technology, but the signature on startup isn't consistent (variable speed fans that are regulated by the temperature of the ambient air).  Monitoring the single circuit takes out any guesswork, and when I'm done characterizing one circuit, I can switch to monitor another.

How do I set up Footprints to use the second MTU, but not to "add" the readings to the NET readings (the second MTU is a subset of the total usage)?

Can I use the second MTU to monitor a 120VAC circuit using just one CT?

G.

TEDSupport6

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Re: Adding a second MTU to monitor a single circuit
« Reply #1 on: March 09, 2011, 06:57:48 AM »
Quote
How do I set up Footprints to use the second MTU, but not to "add" the readings to the NET readings (the second MTU is a subset of the total usage)?

Install your MTU1 on the main leads coming into your panel from the utility, and install MTU2 on the legs supplying the circuit you wish to measure. Then in your System Settings Wizard > System Layout tab, modify your MTU configuration so that MTU1 is LOAD and MTU2 is STAND ALONE. This will allow your circuit to be measured independently however the readings will NOT be added into your cumulative whole-house total.

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Can I use the second MTU to monitor a 120VAC circuit using just one CT?

If you're measuring a single-pole breaker, use one CT and leave the other dangling. If you're measuring a double-pole breaker, use one CT around one leg of power and one CT around the other.