777 overhead electrical panel - 2 versions?

[BBB3]

On the 777 electrical overhead panel, I've seen pictures/diagrams where there seems to be two somewhat different versions of the panel.

On some, there are 2 extra buttons, "IFE/pass seats" and "cabin/utility". Why do some planes have this and some don't?

How does a pilot cut power to the in flight entertainment system if flying a model without this button?

[mikeygd]

Could it be that the version without is for freighters?

[zlin77]

The version with the extra switches was introduced some years after the 777 was in service, I think The Swissair MD11 accident with the IFE electrical fire may have prompted Boeing to modify the electrics...

[wiggy]

Depends on the mod (modification) state of the aircraft. The older panels on un-modified aircraft don't have them, where I work most of the panels are now modified to the new standard, the rest will follow in time.

The cabin crew do have their own switches on their control panels in the cabin so they can isolate seats/IFE as part of smoke and fire drills, regardless of whether there are switches on the flight deck or not. In addition even on the old overhead flight deck panels you can isolate pretty much everything in the cabin by turning the Utility buses off, but since that does things like turning off most of the cabin lighting it's preferable, at least initially, to try just isolating seats and IFE if that's the most likely source of the problem.

[BBB3]

Thanks all!

Wiggy, how do you cut the utility bus without these buttons? Wouldn't you have to take down a main bus as well?

[wiggy]

Just to be clear all the old panels I have seen have the "Utility" button(s) (in much the same place as the new switches). If there aren't any Utility switches at all on the pictures you've seen I wonder of the panel is indeed off a freighter (as mikeygd suggested), but I'm only guessing.