I've just measured two different but conflicting readings using an off the shelf watt meter. My quandary is that these measurements conflict and seem untrustworthy.
My question is: whether measuring from a power board or the wall plug matters or if there is something else at play here that I've missed?
- Reader: Arlec Electrical Meter (PC222)
- Power Board: HPM 12 Socket with surge protection and indicator light
- Device 1 & 2 & 3 Connected to power board. Power board connected to wall plug.
Notes: Device 2 runs under seemingly constant load/utilization for both readings.
1st Reading: 820W measured at power board plug from Device 2. ~247V. PF of 97%
2nd Reading: 220W measured at wall plug of power board with Devices 1&3 on and consuming.
3nd Reading: 630W measured at wall plug of power board with all devices consuming. ~247V. PF of 87%
Edit: These devices are electronic and 2 have computer PSU's.