Why are the HF Circuit Breakers Different?

[Gary Oliver]

Hello,

So there I was sitting through one of "skelsey"'s exceptionally long briefs at the weekend whilst sat in the jump seat, and whilst looking up in despair around 20 minutes in I noticed something semi interesting....

The HF L and R Circuit Breakers are a slightly different design to the rest of the 5A breakers on the overhead.

Any ideas why?  I would assume some kind of shielding for the radio?

Kindest Regards

Confused from Farnborough

[Jeroen Hoppenbrouwers]

Blind guesses.

I doubt that the fact  that these breakers feed a radio have to do with their shape. Power lines need to be shielded from R/F interference elsewhere, not at the breaker.

More likely, in my opinion based on having watched a whole lot of modifications over the last ten years, is that these breakers were replaced once, or were installed at a different time than the rest using equivalent but not identical components.

Even if some HF mods were made later to an aircraft that already had HF, breakers may have been moved around and the new installation kit may have provided new ones just in case.

HF radios are **** *** ****** ** ****** **** (expletives) and replacing them with less **** * * ****** is an all-time favourite of the airlines.



Hoppie

[Roddez]

3 Phase breakers?  The back of the physical breaker is split into three parts, hence the gaps either side.

[John H Watson]

The wiring diagrams show 3 phases with shielded wiring. Don't know why the power cables are shielded.

[Ton van Bochove]

For tactile reasons ?