UK Is this Smart meter installation Safe

[Christopher-Robin]

We have a meter EDMI - ES30B fitted to our property.

I understand from the fact sheet for the smart meter (https://www.edmi-meters.com/wordpress/wp-content/uploads/2018/05/ES-30B-Factsheet-English.pdf), that our meter is rated to withstand 460V which I imagine is under fault conditions rather than constantly. However this would be fine I guess for 3phase / 450V. However ours is split phase system / 480V.

Whilst we got no reply from the supplier EDMI in terms of its application and whether the ES30B 'withstand' rating of 460V could be exceeded, and it can be installed in such a situation. We did however speak to an installer of meters who said:

• Meter's Voltage Rating: If the smart meter is rated for a maximum of 460V, it's not suitable for direct use in a system where the voltage between L1 and L2 is 480V. The meter could be damaged or provide inaccurate readings, and there's a risk of safety hazards.

My concern is that it highlights a ‘safety hazard’? What are these safety hazards.

I have looked at the smart meter installation code of practice SMICoP and can't find anything relating to split phase. I haven’t heard back from our supplier who doesn't know either. If this is a safety risk I need to know my family are safe.

Anyone got any thoughts?

 

[James]

No electrical device should be installed where it will be used outside of its specifications.
if the meter is rated for up to 450v then it should not be used on a 480v supply

 

[davesparks]

The voltage rating of the meter should be for the nominal voltage not the actual measured voltage and will have been designed to operate within the tolerance of the nominal voltage.

Nominal voltage for a split phase supply in the UK is 460V with a tolerance of +10%/-6%

If you have measured your supply at 480V then it is within tolerance and could rise another 6V before reaching it's upper limit.

 

[mainline]

We have a meter EDMI - ES30B fitted to our property.

I understand from the fact sheet for the smart meter (https://www.edmi-meters.com/wordpress/wp-content/uploads/2018/05/ES-30B-Factsheet-English.pdf), that our meter is rated to withstand 460V which I imagine is under fault conditions rather than constantly. However this would be fine I guess for 3phase / 450V. However ours is split phase system / 480V.

Whilst we got no reply from the supplier EDMI in terms of its application and whether the ES30B 'withstand' rating of 460V could be exceeded, and it can be installed in such a situation. We did however speak to an installer of meters who said:

• Meter's Voltage Rating: If the smart meter is rated for a maximum of 460V, it's not suitable for direct use in a system where the voltage between L1 and L2 is 480V. The meter could be damaged or provide inaccurate readings, and there's a risk of safety hazards.

My concern is that it highlights a ‘safety hazard’? What are these safety hazards.

I have looked at the smart meter installation code of practice SMICoP and can't find anything relating to split phase. I haven’t heard back from our supplier who doesn't know either. If this is a safety risk I need to know my family are safe.

Anyone got any thoughts?

Is the supply definitely split phase ? Have you measured the voltage.

 

[Christopher-Robin]

Is the supply definitely split phase ? Have you measured the voltage.

Yes the voltage is actually 492V. Within the tolerance of -6% and +10% for the UK.

The meter datasheet has a 'Withstand Voltage of 460V' and a Maximum Current of 100A. (See data sheet attached.)

I worry because we are 492V (See photo Attached. ) and 2x80A so 160A max.

Data sheet says:
Voltage
• Nominal voltage: 230V, 50Hz, 5(100) Class 1/(MID
Class B)
• Operating range: 176V – 276V
• Minimum Current: 0.25A
• Reference Current: 5A
• Maximum Current: 100A
• Withstand: 460V
• Meter Constant [imp/kWh]: 1000
Current
• WC Range: 0.25/100A, 5/100A
• WC Limit: 3000A for 0.5 cycle
• Disconnect Relay: 100A
• Disconnect Rating: IEC 62052-31 UC3 @ Imax,
240 VAC

 

[Christopher-Robin]

I think part of the problem is that UK and EU voltages were harmonised for single and 3 phase.
In 1995, electricity supply voltages in Western Europe were harmonised to:

• Single Phase : 230Vac (+10% to -6%) = 216.2Vac to 253Vac.)
• Three Phase : 400Vac (+10% to -6% = 376Vac to 440Vac)

However as true split phase is 460Vac (+10% to -6% = 432.4Vac to 506Vac).

The meter I believe is designed for single phase and three phase. But not true UK split phase. (US 120Vac Split phase would be ok I imagine.)

 

[James]

split phase 2 x 80A is 80A not 160A
reading the spec sheet for the 3 phase meter, I believe the voltage rating given is quoted as the phase to Neutral voltage.
therefore i cant see an issue with it as both phases have a nominal voltage of 230V to N

 

[Christopher-Robin]

split phase 2 x 80A is 80A not 160A
reading the spec sheet for the 3 phase meter, I believe the voltage rating given is quoted as the phase to Neutral voltage.
therefore i cant see an issue with it as both phases have a nominal voltage of 230V to N

Thanks for clarifying James. Then if as you say the 'Withstand Voltage' quoted in the EDMI Datasheet is indeed the 'phase to neutral voltage' then it is probably safe and we can sleep a bit easier. We have a custom built transformer that takes the 492V across the 2 phases and turns it into 400V 3 phase. So we do use the 492V across the phases as well as the 246V we measure from phase to the shared neutral.
Its just odd that our meter readings are not inline with consumption still though and we thought this might be it.

 

[Christopher-Robin]

I had received this from another forum, so am slightly lost:

The term "Withstand voltage," particularly in the context of a 3-phase meter, refers to the maximum voltage level that the equipment can handle or tolerate for a specified duration without undergoing any breakdown or damage. In electrical systems, the concept of withstand voltage is crucial for ensuring the reliability and safety of the equipment under operational and fault conditions.

In a 3-phase system, the withstand voltage could be specified in two different contexts:

1. Phase to Neutral: This is the voltage between any one of the three phases and the neutral point. In many three-phase systems, especially those grounded or with a neutral connection, this measurement is essential for equipment that operates with reference to the neutral point. The phase to neutral voltage is typically lower than the phase to phase voltage in a three-phase system.
2. Phase to Phase: This refers to the voltage between any two of the three phases in a 3-phase system. The phase to phase voltage is crucial for equipment directly connected across two phases without any reference to the neutral. In a symmetrical three-phase system, the phase to phase voltage is √3 times the phase to neutral voltage, assuming a sinusoidal and balanced system.

For a 3-phase meter, the specification of withstand voltage could be related to either of these contexts, depending on its design and the intended application within the electrical system. However, more commonly, the critical and specified withstand voltage for such meters and most 3-phase equipment refers to the phase to phase voltage. This is because the phase to phase voltage represents the higher potential difference that the equipment must endure, especially in systems where the neutral might not be present or used.

It's important for electrical professionals to understand these distinctions to ensure that all equipment, including meters, is correctly rated and applied according to the electrical system's characteristics. When selecting or evaluating a 3-phase meter, checking the manufacturer's specifications for withstand voltage is crucial, along with other parameters like current rating, frequency, accuracy class, and the specific application requirements. This ensures that the meter will perform reliably under normal operating conditions and withstand potential overvoltage events without damage.

 

[mainline]

Hasn't the meter got a power quality indicator that also logs events for
RMS Voltage (over, under, swell, sag), Supply Outage, Supply Interruption.

 

[Christopher-Robin]

split phase 2 x 80A is 80A not 160A
reading the spec sheet for the 3 phase meter, I believe the voltage rating given is quoted as the phase to Neutral voltage.
therefore i cant see an issue with it as both phases have a nominal voltage of 230V to N

Hi James, We still haven't managed to get to a definitive answer here. Whilst we do use 230V for the house we also use the phase to phase (492V across the phases) which is connected to a custom built transformer to give us 3 phase for some dairy equipment. Would this matter if as you say the voltage rating is quoted as phase to neutral and not phase to phase.
Many thanks

Robin.

 

[Simon47]

The meter doesn't care what's connected downstream.

 

[davesparks]

Hasn't the meter got a power quality indicator that also logs events for
RMS Voltage (over, under, swell, sag), Supply Outage, Supply Interruption.

No, your average kilowatthour meter downstairs include any of that.

 

[mainline]

No, your average kilowatthour meter downstairs include any of that.

It was in relation to the ops one not the average one.