2 way light circuits - is this crazy?

[plugwash]

His day job?..... Designing and installing electrical installations on aircraft

In some situations such a switching setup may well be a good option (its also very similar to the layout used for bidirectional control of DC motors which may be where he picked it up from) its just domestic/commercial lighting isn't one of them.

I'd imagine aircraft wiring may well not be a TN system either which affects the acceptability of such things.

 

[Spark123]

You'd need a long earth wire it they were on a Terre system

Don't aircraft use some high frequency as well to to reduce the weight of the transformers?

 

[fumb]

Yup,

115V 400Hz (+-5%) is standard so you can get away with smaller transformers, smaller smoother caps etc etc. Although the brownout requirements (which are long enough that you could make a cuppa if the kettle had enough volts ) usually means that capacitators have to be much bigger than you'd like

There's 28V DC too but most equipment is specced to run off 115

 

[TicklyT]

Would the higher frequency have any effect on the likelyhood of an arc between switch contacts etc?

 

[plugwash]

not sure what effect higher frequencies would have on arcs, i'd guess they'd make arcs less likely to break but also make those that were going to break do so sooner.

but anyway i'm sure you can avoid the arcing problem by using suitable switches.

 

[fumb]

In theroy yes I think they are

Although RMS and peak volages are the same regardless of frequency voltages are all the same the probability of breaking or making at peak value is higher. You could maintain the spark over a slightly larger airgap with higher frequency too

In practise I doubt it makes any difference whatsoever. Especially since most equipment doesn't have an on off switch as such. Otherwise the pilots would have to go crawling around the equipment bays to switch the plane on
Plus sooner or later one would be bound to forget to switch the navigation computers on with amusing results