On Wed, 26 Feb 2020 20:26:11 -0500, Tom Biasi
wrote:

On 2/26/2020 1:10 PM, wrote:
If you have 10 gauge, 4-conductor wiring to the pump-house, you are fine doing as you plan. That would be 1-Hot 2-Neutral 3-hot 4-ground into the sub-panel. Then, a double-pole breaker to the pump for 240 Volts, and single pole breakers to light(s) and receptacle(s).

If you do not have an existing separate ground coming from the house, you will need to add a ground rod in the pump-house to ground the sub-panel. And it is still bad practice to use the feeder ground as a neutral - even though they are (should be) bonded in your main house panel. However, this used to happen all the time with heavy appliances being fed with SE Cable such as stoves and dryers, even though they had both 240 and 120 volt-functions on-board.

Good luck with it!

A sub panel should not have the neutral and earth ground bonded. They
need to be separate.
I knew that. Ground and neutral only bonded in the main panel. When I
wired my shop I brought all the grounds from the CNC and manual
machines back to the main panel to avoid ground loops. The control
makers stressed that ground loops are to be avoided.
Eric