The case from a Dell Optiplex GX270 will hold the Kenmore 158 sewing machine’s motor control electronics, because it has a well-grounded metal box inside the plastic shell that will protect fragile humans from line voltages. The GX270 power supply will suffice for the usual stuff, but the bridge rectifier, power transistor, and suchlike require a direct connection to the AC line.
Rather than add another plug, I soldered a nice two-wire line cord to the IEC socket terminals inside the GX270’s power supply:

The cord follows the IEC/EU standard color code:
- Blue – neutral
- Brown – hot
The power supply follows the US standard color code:
- White – neutral
- Black – hot
The nice thing about standard color codes: everybody can have one!
The yellow cable tie anchors the cord to a metal tab that, when bent at right angles, provides a convenient exit from the power supply at exactly the right location:

The power supply mounts with the label facing inward, directly adjacent to the PCI slot covers. The new cord emerges near the bottom, inside the recess that formerly accommodated the board.
Definitely not UL approved, but we’re well beyond that stage anyway…