PM5100 Aux Power Source being the same as load

[foolserrand]

The manual specifies that the Aux power supply, must not be connected to the load side of the measured circuit.

We do not have an auxiliary supply but wish to make use of the PM5100 on a single phase supply.

Although labelled as Aux power supply, my understanding is this is the only way of powering the unit?

What is the result of connecting AUX power supply input to the Voltage inputs? without which I assume the unit will display zero values.

[Mehran_Mehrnia]

Hi @foolserrand 

If this is about the PM5110 as a MID-compliant meter, it meets the requirements that establish standards for the accuracy and performance of measuring instruments used for billing purposes.

Given that the meter can be powered up with line voltage in the range of 100-277 V L-N AC or 100-415 V L-L AC, as mentioned in the user guide, the auxiliary power supply of the meter must be connected in a way that ensures uninterrupted operation in situations where any one or two phases of the measured circuit become de-energized.

Best Regards,

-Mehran

L3 Expert Advanced metering

[foolserrand]

Thank you, I understand the desirability of an uninterrupted supply.

However, as stated we do not have such available and have no requirement for monitoring while de-energized.

What are the consequences of powering the PM5110 from the same single phase load?

[geir_eas_no_bfo · Accepted solution]

Yes of course you can power it from same single load, and there is no other consequences than MID requirements not met. 

BR

GIA

[Mehran_Mehrnia]

Hi @foolserrand 

You're welcome.

The meter itself does not care which source has powered it up, however in MID (Measurement Instrument Directive) meters, the auxiliary power supply must not be connected to the load side of the measured circuit to ensure accurate measurements cause it could create interference in the measurement, affecting the accuracy of the readings by introducing additional voltage or current from the auxiliary supply.

MID regulations require that the auxiliary power supply be isolated from the load side to maintain compliance with standards and ensure reliable operation of the meter.

Best Regards,

-Mehran

L3 Expert Advanced metering

[foolserrand · Accepted solution]

Conflicting advice here, ranging from measurement interference and accuracy to being simply a non compliance issue for MID.

I conclude that for my purposes any suggested inaccuracy would be minimal (if at all) and that it will not harm the unit which was my primary concern.