Best plan to connect oven & cooktop to CH2?

[sandeen]

I have an induction cooktop (2-phase 50A breaker) and a wall oven (2-phase 30A breaker) that I'd like to monitor together on CH2. I'm wondering what the best/simplest setup would be.

I already have two micro-80s, and hoped I could thread both Phase A's through one, and both Phase Bs through the other, but that 50A wire is too thick.

So I could get 2 more micro-80s and connect all four to CH2, but another thread here made it look like that was a somewhat complex setup.

Alternately, I could get two micro-100s, and thread both Phase As through one and both Phase Bs through the other. Would that be simplest?

Or - couldn't I put one micro-80 on each Phase A of each appliance, and just double the values? I suppose that'd take something in the firmware, but for a resistive appliance like the oven, shouldn't that work?

Also, regardless of which micro-XX I choose - they are supposed to be connected in parallel to CH1/CH2, across DUAL and COM, with the burden resistor, correct?

Thanks,
-Eric

[ben]

I have an induction cooktop (2-phase 50A breaker) and a wall oven (2-phase 30A breaker) that I'd like to monitor together on CH2. I'm wondering what the best/simplest setup would be.

I already have two micro-80s, and hoped I could thread both Phase A's through one, and both Phase Bs through the other, but that 50A wire is too thick.

So I could get 2 more micro-80s and connect all four to CH2, but another thread here made it look like that was a somewhat complex setup.

Alternately, I could get two micro-100s, and thread both Phase As through one and both Phase Bs through the other. Would that be simplest?

Or - couldn't I put one micro-80 on each Phase A of each appliance, and just double the values? I suppose that'd take something in the firmware, but for a resistive appliance like the oven, shouldn't that work?

Also, regardless of which micro-XX I choose - they are supposed to be connected in parallel to CH1/CH2, across DUAL and COM, with the burden resistor, correct?

Thanks,
-Eric

The induction cooktop may not have a neutral, but the wall oven likely does (due to the oven fan). So, to combine them both onto one channel, you'll need a CT on each leg. If they both didn't have neutrals, you can monitor them both with a single CT on one leg.

You're best off using a separate CT on each leg. Running multiple wires through one CT is the least desired setup in our opinion due to having to get phasing right, etc.

Micro-80s/40s basically have the same CT settings, so you can pick up a pair of Micro-40s for the 30A breakers. You could actually run all 40s if you wanted to in most situations as by electrical code, a breaker must not exceed 80% of its rating. If it went over for any reason, the reading would just get capped at 40A.

Ben

[sandeen]

Thanks Ben - would you have the same advice if I want/need to use CH2 for this? All the Aux channels are full... that's why I was thinking it might be simplest to thread both phase A's through one CT and both phase B's through the other...

I was underthe impression that it wasn't a trivial thing to add more than 2 CTs to the CH1/CH2 channels.

[ben]

Thanks Ben - would you have the same advice if I want/need to use CH2 for this? All the Aux channels are full... that's why I was thinking it might be simplest to thread both phase A's through one CT and both phase B's through the other...

I was underthe impression that it wasn't a trivial thing to add more than 2 CTs to the CH1/CH2 channels.

It's basically trivial, I would grab 4 Micro-80s and include in your order notes that you need a 4.99 ohm resistor.

Then you just connect the resistor in line with the CTs, all in parallel (phase B CTs reversed).

Ben

[sandeen]

Ok, thanks! I had seen some other post with a more complicated schematic for 4 CTs on CH1/CH2, but maybe that was for non-micro CTs.

Thanks for the info, Ben.

-Eric