Common mode question

[Jester]

I'm designing a metering circuit using this part:  https://www.mouser.com/ProductDetail/Analog-Devices/AD71056ARZ?qs=sGAEpiMZZMt%2foy9k%2f5obbU0YfL1ODTen%252b2QsC6lnqmU%3d

Datasheet: https://www.mouser.com/datasheet/2/609/AD71056-877305.pdf

On page 12 of the datasheet in typical connections, they connect AGND of the AD71056 circuit to the "Phase" wire: for both the voltage and current, so from an earth ground perspective the entire circuit is bouncing around at the phase voltage. I don't see the advantage of this over referencing AGND to the neutral side will be close to 0V (earth potential)?

In my case I will be using PT's and CT's for isolation.

[capt bullshot]

This is usually done when a shunt is used as the shunt is supposed to sit in the live wire. No need to do so if you use a CT, AGND could be tied to neutral then.
Anyway, referencing the AGND to neutral isn't better in terms of safety, as one has to consider the neutral "live" in most cases, so you should isolate the circuit as if it was at live potential.

If you use CT and PT, I'd reference the circuit AGND to safety ground / earth.

[Jester]

This is usually done when a shunt is used as the shunt is supposed to sit in the live wire. No need to do so if you use a CT, AGND could be tied to neutral then.
Anyway, referencing the AGND to neutral isn't better in terms of safety, as one has to consider the neutral "live" in most cases, so you should isolate the circuit as if it was at live potential.

If you use CT and PT, I'd reference the circuit AGND to safety ground / earth.

Thanks, that's exactly what I did.