Author Topic: AC Condenser Monitoring Help  (Read 2399 times)

tonelab77

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AC Condenser Monitoring Help
« on: October 26, 2014, 10:10:37 AM »
I had one 200A CT clipped around both conductors that run to the AC condenser unit. When the AC was turned on, the reading didn't change. I then clipped the CT to one of the conductors and the reading jumped. I tried the other, and the reading was identical, but negative. So it turns out that they were cancelling each other out. I then tried to clip the CT around the main service coming in to that side of the panel and (as expected) the reading was double that of one of the single AC conductors.

From what I can tell, I have two options

1) Get another MTU/CT to monitor both of the AC conductors.
2) Swap conductors around so that all of the guest unit conductors are on one side and the non-guest-unit conductors are on the other side (please see attached image). This way I can just use one CT to monitor the whole guest unit, on one side of the panel.
« Last Edit: October 26, 2014, 10:16:45 AM by tonelab77 »

Support7

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Re: AC Condenser Monitoring Help
« Reply #1 on: October 27, 2014, 05:28:44 PM »
Hello tonelab77,

Why don't you clip one CT around one leg of the AC and the other CT to the other leg? What are you trying to monitor with a single MTU?

Best Regards,

TED Forum Support

RussellH

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Re: AC Condenser Monitoring Help
« Reply #2 on: October 27, 2014, 09:42:22 PM »
I had one 200A CT clipped around both conductors that run to the AC condenser unit. When the AC was turned on, the reading didn't change. I then clipped the CT to one of the conductors and the reading jumped. I tried the other, and the reading was identical, but negative. So it turns out that they were cancelling each other out. I then tried to clip the CT around the main service coming in to that side of the panel and (as expected) the reading was double that of one of the single AC conductors.

From what I can tell, I have two options

Here's another option: Bend the wires so you can get the one CT around both of them - but with the wires going in opposite directions inside the CT so they add instead of canceling out.

RussellH

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Re: AC Condenser Monitoring Help
« Reply #3 on: October 27, 2014, 09:45:59 PM »
Swap conductors around so that all of the guest unit conductors are on one side and the non-guest-unit conductors are on the other side (please see attached image). This way I can just use one CT to monitor the whole guest unit, on one side of the panel.
I don't think that's going to work.  If you look, you'll see the two breakers for the A/C Condenser are tied together.  It needs 240V to work.  If you put them both on the same side, there will be 0V between the two hots and the A/C won't run.