Direct connect voltage limits
You can connect the meter’s voltage inputs directly
to the phase voltage lines of the power system if the power system’s
line-to-line or line-to-neutral voltages do not exceed the meter’s
direct connect maximum voltage limits.
The meter's voltage measurement inputs are rated by the manufacturer for up to 277 V L-N / 480 V L-L. However, the maximum voltage allowed for direct connection may be lower, depending on the local electrical codes and regulations. As per installation category II the maximum voltage on the meter voltage measurement inputs should not exceed 277 V L-N / 480 V L-L for CAT III and 347 V L-N / 600 V L-L for CAT II.
If your system voltage is greater than the specified direct connect maximum voltage, you must use VTs (voltage transformers) to step down the voltages.
| Power system description | Meter setting | Symbol | Direct connect maximum (UL / IEC) | # of VTs (if required) | ||
|---|---|---|---|---|---|---|
| Display (meter) | Display (communication) | Installation category III | Installation category II | |||
| Single-phase 2-wire line-to-neutral | 1PH2W LN | 1PH 2Wire L-N | ≤ 277 V L-N | ≤ 347 V L-N | 1 VT | |
| Single-phase 2-wire line-to-line | 1PH2W LL | 1PH 2Wire L-L | 480 V L-L | 600 V L-L | 1 VT | |
| Single-phase 3-wire line-to-line with neutral | 1PH3W LL With N | 1PH 3Wire L-L with N | ≤ 277 V L-N / 480 V L-L | ≤ 347 V L-N / 600 V L-L | 2 VT | |
| 3-phase 3-wire Delta ungrounded | 3PH3W Dlt Ungnd | 3PH 3Wire Ungrounded Delta | 480 V L-L | 600 V L-L | 2 VT | |
| 3-phase 3-wire Delta corner grounded | 3PH3W Dlt Crnr Gnd | 3PH 3Wire Corner Grounded Delta | 240 V L-L | 600 V L-L | 2 VT | |
| 3-phase 3-wire Wye ungrounded | 3PH3W Wye Ungnd | 3PH 3Wire Ungrounded Wye | 480 V L-L | 600 V L-L | 2 VT | |
| 3-phase 3-wire Wye grounded | 3PH3W Wye Gnd | 3PH 3Wire Grounded Wye | 480 V L-L | 600 V L-L | 2 VT | |
| 3-phase 3-wire Wye resistance-grounded | 3PH3W Wye Res Gnd | 3PH 3Wire Resistance Grounded Wye | 277 V L-N / 480 V L-L | 347 V L-N / 600 V L-L | 2 VT | |
| 3-phase 4-wire open Delta center-tapped | 3PH4W Opn Dlt Ctr Tp | 3PH 4Wire Center-Tapped Open Delta | 173 V L-N / 347 V L-L | 347 V L-N / 600 V L-L | 3 VT | |
| 3-phase 4-wire Delta center-tapped | 3PH4W Dlt Ctr Tp | 3PH 4Wire Center-Tapped Delta | 173 V L-N / 347 V L-L | 347 V L-N / 600 V L-L | 3 VT | |
| 3-phase 4-wire ungrounded Wye | 3PH4W Wye Ungnd | 3PH 4Wire Ungrounded Wye | ≤ 277 V L-N / 480 V L-L | ≤ 347 V L-N / 600 V L-L | 3 VT or 2 VT | |
| 3-phase 4-wire grounded Wye | 3PH4W Wye Gnd | 3PH 4Wire Grounded Wye | ≤ 277 V L-N / 480 V L-L | ≤ 347 V L-N / 600 V L-L | 3 VT or 2 VT | |
| 3-phase 4-wire resistance-grounded Wye | 3PH4W Wye Res Gnd | 3PH 4Wire Resistance Grounded Wye | ≤ 277 V L-N / 480 V L-L | ≤ 347 V L-N / 600 V L-L | 3 VT or 2 VT | |