I replaced a Westinghouse EP Single Phase S10N05S51B 120 X 240, 12 X 24 Transformer, which was used to power out in-ground poolâÂÂs light with a Westinghouse S10N0551A. Before disconnecting the old transformer, I took photos of the connections to be sure I connected the new one correctly which are:

H1H3 (Black In)
H2H4 (White in)
X1X3 (Black out)
X2X4 (White out)
Ground in to ground out.

I am positive I connected the new transformer exactly like the old one and, with the IN wires connected and no wires attached to the OUT side, power is being sent out through X1X3.

My problem is, every time I connect ANY wire (the actual load wires or a spare piece of wire) to X1X3 or even X2X4, the X1X3 wires stop sending power out. When I remove the wire, then X1X3 will again send power out. For the life of me I canâÂÂt figure this out. Anyone have any ideas what IâÂÂm doing wrong?