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In a message dated 5/27/2001 9:39:43 PM Pacific Daylight Time, lancair.list@olsusa.com writes:

<< The power to the pressure switches should not come from the hyd pump
circuit. Those little bity wires wouldn't  be saved by a 50 amp breaker. >>

I will be wiring my hydraulic circuit with a 50 amp breaker whose output side goes both to the pump and also to a smaller fuse.  The little bitty wires to the relays are protected by the fuse.  This fuse will protect the wiring to the relays.  I can't envision a situation where I would want to disable the pump but keep the relays powered, so one breaker cuts off everything.  The fuse is needed to protect the little wires going to the relays.  Of course, the wire from the 50 amp breaker to the fuse has to be a fat one (eventually I'll run Scott Dahlgren's wiring sizing spreadsheet and quantify "fat").

Why a fuse and not another breaker?  I have a Control Vision power distribution system mounted to the slanted panel on the old-style 320/360 panel, plus separate breakers for hydraulic pump, pitot heat, and main power to the power distibution system.  There's no room for a pump relay circuit breaker, but there is room for a fuse.  It would be aesthetically unpleasing if I mounted another breaker elsewhere.  Otherwise, a breaker would be fine.

- Rob Wolf

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