120V north american-centric advice placed here.

I built one using 9 BLB compact flourescents, with bases up in a box that the printing frame gets slid under the lights.

I used 'screw shell' lamp sockets, and wired them all together in parallel with 'lamp cord'.

Lamp cord is 2 conductor stranded copper wire. One side of the pair has a ridge or ridges. Wire that side up to the silver screw of all of the sockets, and the wide blade of the plug you plug in.

If you add a switch, place it in the other than ribbed line, that is connected to the narrow plug blade.

I added about 6 3/4" holes in the back of my unit at the top and the door at the front leaves a gap when closed.

That seems to be sufficient ventilation to dissapate the modest heat these lamps generate when left to run for an hour, which is the longest cyanotype exposure I use, when dealing with overly dense enlarged negatives.