The GEC Z8403 is a rare lantern nowadays, and they run a 250-400w MA/V lamp. Lots of them were retrofitted so they could run SON lamps.

Wood Lane, Slough, berkshire

This GEC Z8403 is on Wood Lane in Slough, berkshire. It’s on a rusty S&L column, and it runs, or used to run a 250w SON lamp. This installation is visible from the M4, as the M4 is adjacent to it.

The column door isn’t locked, so it can be opened. It has a GEC 250w SON ballast, and a capacitor. There is no ignitor visible, so it could run on SON-I lamps with a internal snap starter.