ACS37800 Power Monitor - readings for 240VAC are not correct

Components & Accessories Power
1

I purchased 2 of these modules. From the data sheet for the ACS37800 I have calculated that the R Sense value should be 2.7K ohms. This was arrived at as follows, voltage measured is up to 250VAC RMS so a safe margin would require 1.4142 x 260 = 353.55, R SENSE = (4,000,000 x 0.25)/(367.69-0.25) = 2721. I fitted a 0.1% accuracy 2.7K ohm resistor in place of the one fitted and connected LO to the neutral line of single phase AC.

Having implemented the library, I can read the VRMS and IRMS measures, however, with no load (therefore no current) IRMS is 0.06A and VRMS is 373VRMS whereas my DMM reads 246VRMS - 2 questions; what could be the reasons that the voltage reading exactly 1.5 times what it should read and why is the current reading offset from zero?

2

From https://github.com/sparkfunX/Qwiic_Power_Meter-ACS37800

Although the ACS37800 power monitoring IC is capable of monitoring AC power at high line voltages, the SparkX Power Meter is designed for Safety Extra Low Voltage (SELV) applications of up to 60VDC only. Its use in AC power systems is not recommended.

It doesn’t look like that board layout meets creepage and clearance rules for line voltage isolation; I am seeing only 1.75mm spacing between the low voltage ground pour and the AC line connections.