Table 110.34(A) & a delta-wye starter

[trallio]

When using Table 110.34(A) to determine minimum clear working space, the first column says "Nominal Voltage to Ground".

I have a 13.8KV delta-wye starter. In the Wye condition, volts to ground would be 8KV (approx). Then I could use the 2501-9000V row of the table.

In this application, would the voltage to ground for the delta be considered 8KV or 13.8KV?

If 13.8KV then, I need to need the next row "9001-25000V"

 

[don_resqcapt19]

This would have to be based on the supply voltage to the starter. If it is a grounded wye, then voltage to ground would be ~8kV. If the supply is ungrounded delta the votlage to ground would be 13.8 kV.

Voltage to Ground.

For grounded circuits, the voltage between the given conductor and that point or conductor of the circuit that is grounded; for ungrounded circuits, the greatest voltage between the given conductor and any other conductor of the circuit.​

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[trallio]

correct

correct

I believe this is correct. In fact, what we have is actually used as a wye-delta and the wye is grounded. (This is for a furnace.) Therefore, I believe that, even in the delta configuration, I can use ~8KV as the nominal voltage to ground.