Tap off one side of 240V

[Petertaylor]

Our deep well has an underground 240 line running to it. Nearby is a shed and I would like to add a few lights inside. I know that tapping 120 off one side of the pump is not code, but would cause any problems?

[rwe2156]

[fireproof suit on]

I've done it................no problems.

But you need a neutral. Some 220 circuits have a neutral, some don't.

[kencombs]

OK only if it is a 4 wire 240 circuit. Ground and neutral in addition to the hot wires. Otherwise the bare ground would be carrying current which is a no no.

[Roly]

OK only if it is a 4 wire 240 circuit.  Ground and neutral in addition to the hot wires.  Otherwise the bare ground would be carrying current which is a no no.

 The neutral is the important part as I doubt it will have one.   A white wire will not be a neutral if just a black and white going to the pump.  Also fuse the shed circuit for the wire size you are adding.    A couple of lights wont matter but a large load may trip the breaker to the well when the pump starts.   Roly

[joe1086]

Neutrals aside....well is on a 30 amp breaker? Won't 12 or 14 ga wire off that breaker to the shed invite risk should someone else decide to use power there?

[jlanciani]

Where is the pump controller located? If its in the house you'll only have power in the shed when the pump is running...

[Snipe Hunter]

Where is the pump controller located? If its in the house you'll only have power in the shed when the pump is running...

[Petertaylor]

Thank you for the knowledgeable comments and questions. The underground wire out of the basement is 10-2 with ground. 30 amp breaker. The pressure switch is in the basement. I hadn’t realized that the voltage at the pump is nil when the pump is off. So my idea won’t work. Thanks again.

[Snipe Hunter]

Thank you for the knowledgeable comments and questions. The underground wire out of the basement is 10-2 with ground.  30 amp breaker.  The pressure switch is in the basement.  I hadn’t realized that the voltage at the pump is nil when the pump is off.  So my idea won’t work.  Thanks again.

The pressure switch (contactor) which turns on and off the pump is usually real close to your well pressure tank inside the house. So the conductors between it and the pump are dead until the pressure drops and the contactor closes and sends power to the pump