For what it's worth..
400 watt, 277 volt, Advance ballast specs are:
Operating amps; 1.7 Input watts, 454
400 watt Lumark Hi-bay...
Starting Amps....1.40
Operating Amps....1.70
Based on the above, I would fuse at 3 amps maximum, midget fuse, 480 or 600 volt.
There are fractional amperage fuses available (2.25; 2.50) but they are pricey..
PS: Don, the sources for the above info are Advance Catalog, and WWGrainger catalog...
Another good source is Venture Lighting, they must have a web site.
John
[This message has been edited by HotLine1 (edited 12-10-2002).]
