Voltage and current card

Who it’s for

Anyone who thinks in terms of “nominal, plus or minus a tolerance” asks “is this reading within range, or has it drifted outside the band?” — not a raw threshold number they’d have to reverse-engineer. A plant electrician at a switchboard watches for phase imbalance, the classic early sign of a burning three-phase motor. A duty engineer on a UPS decides whether the input has sagged enough to bring up the generator. A service engineer checks whether a solar inverter’s string voltage has drifted outside its expected range, an operator confirms a diesel generator reached nominal in its first thirty seconds after starting, and a mechanic watches a pump’s current creep above normal, the kind of drift that shows up weeks before a bearing fails.

What it does

The card reads each value against a nominal-plus-tolerance band instead of a raw threshold, matching how an electrician actually thinks — “230 nominal, 10 percent tolerance,” not “alarm at 207 volts.” A voltage reading of 238V against the default 230V ±10% band sits inside the zone in green; the same circuit at 265V reads red, on a scale that runs to twice the tolerance width, so you can see how far out a reading is, not just that it is out.

• Phase mode is one setting — Single-phase or 3-phase — and only the four key-name fields relevant to that mode are shown, not eight
• A position bar under every value shows where the reading sits on that twice-the-tolerance scale, so an out-of-range value visibly lands outside the zone instead of clamping to the edge
• In 3-phase mode, one Phase imbalance figure — the spread between the highest and lowest phase voltage, as a percent of nominal — gets its own warning threshold and a badge in the header when it is exceeded
• A phase that is missing or stale shows as a dash in its own status color; it does not take down the rest of the card
• Reads voltage and current against the band you set; it does not measure frequency, power, or energy, and it does not control anything

How to set up

Data keys

Key	Role	Type	Description
Voltage key (Single-phase default voltage; 3-phase defaults voltageL1, voltageL2, voltageL3)	Voltage	Timeseries or Attribute	Optional — matched by literal key name, set under Settings → Voltage
Current key (Single-phase default current; 3-phase defaults currentL1, currentL2, currentL3)	Current	Timeseries or Attribute	Optional — matched by literal key name, set under Settings → Current

Bind keys on the Data tab with names that exactly match the text set under Settings → Voltage and Settings → Current — there is no per-key Role field the way some cards use; matching is by literal name only. Voltage and Current are independent: bind one, both, or in 3-phase mode any subset of the three phases, and only the rows with a live key appear. With no datasource bound at all, the card shows a setup message. With a datasource bound but no key name matching what the settings expect, it shows a different message asking you to check the names. A key that has gone stale or never reported renders as a dash in Missing phase color instead of an error.

Phase mode

Setting	Default	Effect
Phase mode	Single-phase	Single-phase reads one voltage/current pair from Voltage key name and Current key name. 3-phase reads L1/L2/L3 from six separate key-name fields and turns on the Phase imbalance figure

Phase mode is a manual switch rather than something inferred from which keys are bound — that is what lets the settings panel show only the four key-name fields that apply, instead of all eight at once.

How to customize

Voltage and current thresholds

• To change what counts as in-range — adjust Nominal and Tolerance (%) under Settings → Voltage or Settings → Current.
• To relabel the unit shown — edit Unit under Voltage or Current (defaults are V and A).

Imbalance

• To change the imbalance warning level — adjust Warning threshold (%) under Settings → Imbalance; the badge and the imbalance figure’s color both follow this threshold.
• To recolor the imbalance value and badge — adjust Imbalance color under Settings → Imbalance.
• To hide the imbalance badge — turn off Show imbalance badge under Settings → Header (only available in 3-phase mode).
• To hide the imbalance figure entirely — turn off Show imbalance under Settings → Imbalance.

Display

• To change status colors — adjust In-range color, Out-of-range color, and Missing phase color under Settings → Display.
• To change how quickly a phase is marked missing — adjust Stale after (minutes); 0 turns the check off.
• To change decimal precision — adjust Decimal places.
• To hide the last-updated time — turn off Show last updated.
• To restyle the text — adjust Value font and Label font.

Tips

• Phase imbalance is calculated from Voltage only, shown as one figure rather than a separate number for each quantity — current draw already gets its own per-phase reading, so it does not need a second imbalance figure.
• Bind all three L1/L2/L3 voltage keys before relying on Phase imbalance; until every phase reports, the figure shows “n/a” instead of a percentage.
• Set Stale after (minutes) close to how often your device actually reports, so a normal gap between readings is not shown as a missing phase.
• Because matching is by literal key name rather than a Role field, give each device with different key names its own copy of this widget rather than reusing one instance across mismatched devices.