How to Specify Panel Meters for a New Industrial Switchboard with Acrel and ProSense Instruments
A panel meter is a small item until it is wrong. Then it becomes a door cutout that cannot be reused, a current input that does not match the CTs, a display nobody can read, or an auxiliary supply that the control panel does not provide.
Good switchboard metering starts before the panel shop cuts steel. The right choice depends on four groups of requirements:
Mechanical fit
Display and measurement needs
Auxiliary power
Current and voltage input method
Acrel and ProSense both have useful instruments for industrial switchboards, but they are not selected the same way. Acrel is often a strong fit where the board needs multi-function electrical monitoring, energy data, alarms, and communication. ProSense-branded panel instruments are often a good fit for clear local indication of a specific voltage, current, process, or transducer signal.
The best specification does not begin with a brand. It begins with the exact circuit, door, supply, and operator requirement.
Start with the job the meter must do
Before comparing part numbers, define what the meter must show and why.
A main incomer meter has a different job from a feeder ammeter. A generator synchronising panel has different needs from a pump control switchboard. A tenant energy meter has different requirements from a local voltage indicator.
Write the metering purpose in plain terms:
Show the operator whether the supply is healthy
Display current draw on a motor feeder
Record energy use for a process line
Provide Modbus data to a PLC, HMI, or SCADA system
Alarm on overload, phase loss, under-voltage, or low power factor
Indicate a 4-20 mA signal from a current transducer
Replace analogue meters with digital equivalents
This first step prevents over-specifying simple points and under-specifying critical ones.
For example, a motor control centre feeder may only need a local current display. A ProSense digital panel meter paired with the correct CT or current transducer may be enough. A main LV switchboard incomer may need voltage, current, frequency, power factor, kW, kvar, kVA, kWh, demand, alarms, and communications. That is where an Acrel multi-function power meter is usually the more suitable class of instrument.
Check the panel dimensions before selecting the meter
Mechanical fit is one of the most common causes of rework. A meter can meet every electrical requirement and still fail the job if it does not fit the door.
The panel specification should confirm these details before ordering:
Mechanical requirement | What to confirm |
Cutout size | Exact required door opening from the meter datasheet |
Bezel size | Visible front dimensions and spacing between meters |
Mounting depth | Clearance behind the door, including terminals and wiring |
Door thickness | Mounting clip range and gasket compression |
Front protection | IP or NEMA rating needed at the switchboard face |
Terminal access | Space for ferrules, CT wiring, voltage wiring, and test links |
Door swing | Clearance from inner escutcheons, ducts, and equipment |
Heat and ventilation | Ambient temperature range inside the enclosure |
Many industrial meters follow common formats such as square panel meters or DIN-style rectangular cutouts, but common is not universal. Do not assume that a replacement or alternative model will fit the same aperture.
For a new switchboard, lock in the cutout only after the meter model is approved. Once the door is punched, the project has much less flexibility.
Acrel panel meters may be available in common switchboard sizes depending on the series and function. Multi-function meters are often selected for 3-phase panels and may require larger face space than a simple indicator. ProSense panel instruments can be compact, especially when used for single measured values, but their exact cutout, depth, and mounting clip arrangement still need checking against the datasheet.
Also check how the meter seals to the enclosure. If the switchboard is in a dusty plant room, washdown area, or outdoor kiosk, the front rating matters. The meter face, gasket, and installation method must support the enclosure rating expected at the door.
Define the display requirements in operator language
A clear display is not just a preference. It affects fault finding, safety, and day-to-day operation.
Start with the information the operator needs at the panel face. Then decide how much detail belongs on the meter and how much belongs in a PLC, HMI, or SCADA system.
Common display requirements include:
Voltage by phase and line-to-line
Current by phase
Frequency
Power factor
Active power in kW
Apparent power in kVA
Reactive power in kvar
Imported and exported energy
Maximum demand
Harmonic indication where required
Alarm status
Communication status
Acrel multi-function meters are relevant where several of these values need to appear in one instrument. They can reduce the number of separate meters on the door and provide a single measurement point for switchboard incomers, tie breakers, capacitor panels, and major feeders.
ProSense-branded panel instruments are more relevant where the requirement is a focused display, such as one AC current value, one DC voltage value, or a scaled process signal from a transducer. They are useful when the switchboard needs a simple readout rather than a full power monitoring device.
When writing the display section of the specification, avoid vague terms such as “digital meter” or “power meter.” Use measurable requirements.
Good display details include:
Number of visible digits
Engineering units shown on screen or on labels
Decimal place requirement
Display colour if the site uses colour conventions
Viewing distance from the normal operating position
Viewing angle if the board is tall or low
Backlight requirement
Alarm indication method
Phase scrolling or fixed phase display
Password protection for settings
Local reset requirement for demand or energy values
For basic indication, a bright numeric display may be better than a menu-driven meter. For a main switchboard, a menu is acceptable if the home screen shows the most important values and the configuration cannot be changed accidentally.
Match the auxiliary supply to the switchboard design
Every powered meter needs an auxiliary supply unless it is self-powered from the measured circuit. This is a simple detail that causes many site delays.
Confirm the auxiliary supply before the purchase order:
Auxiliary supply question | Why it matters |
Is 24 VDC available? | Many control panels already have a DC power supply |
Is AC auxiliary power available? | Some meters use a wide-range AC or AC/DC supply |
Must the meter stay alive during supply loss? | A UPS-backed control supply may be needed |
Is isolation required? | Measurement circuits and control supplies may need separation |
What is the meter burden? | The control power supply must have spare capacity |
How will it be protected? | Use suitable fusing or circuit protection |
What happens after power recovery? | Settings, demand values, and outputs should behave as expected |
Acrel meters used for energy and power monitoring may need a dedicated auxiliary supply separate from the voltage measurement input, depending on the model. Some meters support wide-range supplies, but the exact range must be taken from the selected datasheet.
ProSense panel instruments may be available in versions for common control voltages, including DC-powered indicators and AC-powered meters depending on the product family. Do not select from the front appearance alone. Two meters that look similar can have different power supply requirements.
A good specification states the supply clearly, for example:
The meter auxiliary supply shall be 24 VDC from the protected control supply
The meter shall operate from the available AC auxiliary supply in the switchboard
The meter shall retain configuration after loss of auxiliary power
The meter supply shall be fused separately from measurement voltage inputs
If the switchboard includes PLC monitoring, it is often better to power metering devices from the same control supply philosophy as the PLC and communication equipment. This keeps data available during controlled shutdowns, where required.
Select current inputs from the circuit, not from habit
Current input selection is where metering mistakes become expensive. The meter, CT, wiring, and circuit rating must all match.
Common current input methods include:
Direct current input for small loads, if the meter allows it
1 A or 5 A CT secondary inputs for AC circuits
Current transducers with DC outputs
Shunt inputs for DC circuits
Hall-effect sensors for DC or mixed current applications
Rogowski coils for high-current AC applications, where supported by the meter system
Most switchboard power meters use CT inputs for AC current measurement. Acrel multi-function meters are commonly selected with CT ratios suited to the feeder or incomer. The selected model must match the CT secondary current, such as 1 A or 5 A, and the CT ratio must be programmed correctly during commissioning.
ProSense panel instruments may be used with a current transformer, current transducer, or process signal depending on the exact input type. For example, if the meter accepts a 4-20 mA input, the current transducer must scale the load current into that signal range. If the meter accepts an AC current input directly, the input range and CT secondary must match the datasheet.
Key CT details include:
CT requirement | What to specify |
Primary current | Match the circuit rating and expected load |
Secondary current | Match the meter input, commonly 1 A or 5 A |
Accuracy class | Select for indication, control, or energy measurement duty |
Burden | Include meter input burden and cable length |
Window size | Fit around the cable or busbar |
Mounting type | Split-core, solid-core, busbar-mounted, or cable-mounted |
Polarity | Mark P1/P2 and S1/S2 consistently |
Shorting method | Provide CT shorting terminals where required |
Never leave a CT secondary open while primary current flows. CT circuits need suitable shorting or test links for safe maintenance and meter replacement.
For DC switchboards, do not assume an AC CT will work. DC measurement usually needs a shunt, Hall-effect sensor, or DC transducer. The meter input then needs to match the output signal, such as millivolts from a shunt or a scaled DC analogue signal.
Do not ignore voltage inputs and wiring configuration
Even if the main concern is current, a power meter also needs voltage inputs to calculate power, energy, and power factor.
Confirm the system arrangement:
Single-phase
3-phase, 3-wire
3-phase, 4-wire
Grounded or ungrounded system
Direct voltage connection or voltage transformer input
Nominal voltage and maximum operating voltage
Frequency range
Required fusing for voltage inputs
Acrel multi-function meters must be wired and configured for the actual network. A 3-phase, 4-wire meter setup applied to a 3-wire system will give misleading data. The same applies to CT polarity. One reversed CT can create incorrect kW and power factor readings even when current values look reasonable.
ProSense instruments used as voltmeters need the input range matched to the measured voltage. If the circuit voltage is higher than the meter input rating, use a suitable voltage transducer or transformer.
Decide whether communication and outputs are required
Local display may be enough for small feeders, but many new switchboards need data.
Acrel meters are often selected when the board needs communication such as RS-485 with Modbus, depending on model options. That can support energy monitoring, load studies, alarms, and integration with supervisory systems.
ProSense panel instruments may offer relay outputs, analogue retransmission, or communication on some models, but this must be checked by exact part number. For many simple switchboard points, a local display and alarm relay are all that is needed.
Specify communication clearly:
Protocol required
Network type
Baud rate or site standard
Addressing method
Values to be mapped
Alarm outputs
Relay contact ratings
Analogue output scaling
Isolation between inputs, outputs, and supply
If the meter will connect to a PLC, define who owns the scaling. A CT ratio can be set inside the meter, inside the PLC, or both by mistake. Only one device should apply the main scaling factor unless the system is deliberately designed otherwise.
Use Acrel where multi-function electrical monitoring is needed
Acrel instruments are a good fit for switchboard applications that need more than one displayed value from the same electrical point.
Typical uses include:
Main incomers
Generator incomers
Bus couplers
Major outgoing feeders
Power factor correction panels
Energy monitoring points
Distribution boards with communication to a central system
When specifying an Acrel meter, confirm:
Panel cutout and mounting depth
1 A or 5 A CT input compatibility
Voltage input range and wiring mode
Auxiliary supply voltage
Displayed parameters
Accuracy class suited to the task
Communication option if required
Alarm or digital output requirements
Programming access and password control
Do not select the highest-featured model by default. If the switchboard only needs a local ammeter, a multi-function meter may add complexity without adding value. Use Acrel where the extra measurements, data, and communication are part of the requirement.
Use ProSense where clear single-point indication is the priority
ProSense-branded panel instruments make sense where the switchboard needs a defined local reading from a defined signal.
Typical uses include:
AC current indication on a feeder
DC voltage indication from a battery system
Scaled display from a 4-20 mA current transducer
Process value indication on utility panels
Simple operator readout for a pump, fan, or heater circuit
Retrofit replacement where the door cutout matches
When specifying a ProSense panel instrument, confirm:
Accepted input signal
Display range and scaling
Auxiliary supply requirement
Cutout size and depth
Decimal places and engineering unit label
Relay output or analogue output need
Environmental rating at the front face
Compatibility with the transducer or CT being used
A ProSense meter is often the cleaner choice when one measured value must be obvious at a glance.
Build the selection table before issuing the switchboard drawings
The safest way to specify panel meters for a new industrial switchboard with Acrel and ProSense instruments is to create a schedule for every metering point.
Use one row per meter and include enough information for purchasing, panel building, wiring, and commissioning.
Meter point | Required detail |
Location | Incomer, feeder, generator, bus section, or auxiliary panel |
Function | Ammeter, voltmeter, power meter, energy meter, or process display |
Preferred instrument type | Acrel multi-function meter or ProSense panel instrument |
Door cutout | Exact size from selected datasheet |
Mounting depth | Required rear clearance |
Supply | Auxiliary voltage and protection method |
Voltage input | Direct, VT, single-phase, 3-wire, or 4-wire |
Current input | CT ratio, 1 A or 5 A, transducer, shunt, or direct input |
Display | Parameters, units, digits, decimal places, and home screen |
Outputs | Relays, analogue outputs, pulse outputs, or communications |
Network | Protocol and address if connected |
Labels | Meter tag, circuit name, units, and CT ratio |
Commissioning checks | Rotation, polarity, scaling, alarms, and communication |
This schedule becomes the control document. It helps the electrical designer, switchboard builder, procurement team, and commissioning technician work from the same assumptions.
What a good final specification looks like
A strong meter specification is precise without being overloaded. It should read like a set of buildable requirements, not a wish list.
For a main incoming supply, the specification might call for an Acrel multi-function power meter with:
3-phase measurement matched to the system wiring
CT inputs matched to the selected CT secondary
Voltage inputs suitable for the network or VT secondary
Display of voltage, current, power, power factor, frequency, and energy
Auxiliary supply matched to the switchboard control voltage
RS-485 Modbus communication if required by the site
Door cutout, depth, and front rating confirmed from the datasheet
For a feeder current display, the specification might call for a ProSense panel instrument with:
Input matched to the CT, transducer, or signal conditioner
Scaling to show primary current in amps
Display brightness suited to the switchroom
Auxiliary supply matched to the control panel
Cutout and depth approved before door manufacture
Labels showing circuit name and engineering units
The difference is the requirement. Acrel is not automatically better because it measures more. ProSense is not automatically better because it is simpler. The correct choice is the one that fits the electrical signal, the mechanical space, the operator need, and the control system.
A panel meter should be specified as part of the switchboard system, not as an accessory. Confirm the door dimensions, display purpose, auxiliary supply, current input, voltage input, and communication needs before the enclosure is cut and wired. That discipline prevents avoidable redesign and gives the finished switchboard metering that operators can trust.
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