Voltage reading at this point

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kwired

Electron manager
Location
NE Nebraska
As is drawn there can be no voltage measured across the switch that is indicating 120 volts across it. If this is a troublshooting question and the drawing is representing what you are supposed to have - then there will be 120 volts measured across that switch if there is a ground fault on the "load side" conductor connected to the switch. Otherwise if there are no faults and everything is installed as drawn and in state shown in the drawing (open vs closed contacts) there should be no voltage to measure across that switch.

Since this is a training thing, there is either a mistake or we don't fully understand what the circumstances are supposed to be when this measurement is taken.
 

Besoeker

Senior Member
Location
UK
As is drawn there can be no voltage measured across the switch that is indicating 120 volts across it. If this is a troublshooting question and the drawing is representing what you are supposed to have - then there will be 120 volts measured across that switch if there is a ground fault on the "load side" conductor connected to the switch. Otherwise if there are no faults and everything is installed as drawn and in state shown in the drawing (open vs closed contacts) there should be no voltage to measure across that switch.

Since this is a training thing, there is either a mistake or we don't fully understand what the circumstances are supposed to be when this measurement is taken.
See post #17.
 

kwired

Electron manager
Location
NE Nebraska
See post #17.
But if all switch contacts are in the state they are shown in - there is no neutral or ground connection to measure to. We bring in ungrounded conductor to top of switch being measured, and on other side we have conductor that "dead ends" in three different places. The start switch, the holding contact and the load contact. If there is voltage measured it is capacitive in nature (likely being disregarded for such a training application), or there is a fault or other item that is not shown in the drawing involved. As drawn there can be no voltage across that switch.
 

Besoeker

Senior Member
Location
UK
But if all switch contacts are in the state they are shown in - there is no neutral or ground connection to measure to. We bring in ungrounded conductor to top of switch being measured, and on other side we have conductor that "dead ends" in three different places. The start switch, the holding contact and the load contact. If there is voltage measured it is capacitive in nature (likely being disregarded for such a training application), or there is a fault or other item that is not shown in the drawing involved. As drawn there can be no voltage across that switch.
No disagreement with that.
 
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