Square D 30/50 wiring question

[Kimura]

My super asked me to replace some 30 year old nm for a customer.

Upon entering the residence, everything was functioning but they wanted it to look more professional. I planned to replace with a couple of whips.

The wiring is for a Square D 30/50 pump. It’s fed by two 20a (in tandem) at the panel. Here’s where things get wonky:

-One 12/2 hits a switch near the pump , which feeds to the left side of the Square D. Standard disconnect it appears

-The other 12/2 goes directly from the panel and into the right side of the Square D. I’ve never been able to detect voltage on this side AT ALL

My question: is this a common way to wire a well pump? Not understanding why it was done in this manner.

Journeyman residential electrician, and this is the first one I’ve come across

thanks

 

[iceworm]

By "Square D 30/50 pump", do you mean a pressure switch and well pump? If so, the wiring sounds about right.

Two pole CB feeding 240V to the pressure switch. I've seen both 2pole and 1pole pressure switches. The pressure could be breaking both hot leads, or just one. From the pressure switch, the wiring goes to a on-off switch. That one should be 2pole. From the on-off switch, to the pump. I would have put the on-off switch ahead of the pressure switch.

As for why the feed from the panel to the pressure switch is dead, that is a puzzle - especially if the pump is working.

 

[Hv&Lv]

This may be a dumb question, and please forgive if it is...

square D has two outside for lines and two inside for motor.
Could it be someone before just put one line on the left side, like a switch loop, with the hot going to one screw on far left, and the return going to the middle left screw? The other two on the other side could be taped off somewhere?

My sister had an OLD house with an old 120V pump. It replaced an older 240V pump. Why 120, I have no idea. I had to replace the switch. That made for the longest FREE day I’ve ever had figuring out what they had there...

 

[synchro]

-The other 12/2 goes directly from the panel and into the right side of the Square D. I’ve never been able to detect voltage on this side AT ALL

Just to clarify this, even when you get the pump running there's no voltage on the right side cable? A Pumptrol switch is usually a DPDT with the line input wired through one knockout and the load through the other knockout. If there's no voltage on the right side when the pump is running then Hv&Lv may be right about a switch loop.
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[Kimura]

So I didn’t take into consideration to check voltage while the pump was running. I had the homeowner run his irrigation system and sure enough , the right side gets energized when the pump kicks on. Thanks for the assistance with my brain fart