In planning the instrument panel I notice the circuit breakers (or fuses. Please do not comment on the difference between these two. It is not the point here.) consume a large area. A significant portion of the area is occupied by the labels.
In one Remos some devices share one circuit breaker. The grouping is:
1: MasterFuse/EMS; 2: Horizon/EFIS/ELT; 3: FuelPump/PositionLight/AntiCollisionLight; 4: LandingLight/InstrumentLight/RPM; 5: Trim/Flap； 6: Starter/Prop; 7: GPS/Comm2/12V; 8: Directional Gyro; 9: EFIS/Horizon; 10: TurnCoordinator/AP; 11: XPDR/Encoder; 12: Comm1/Intercom.
In another Remos, the grouping is different:
1: Master; 2: Starter Relais; 3: Trim/Flap; 4: AntiCollisionLight; 5: LandingLight/PanelLight; 6: PositionLight; 7: Skyview LH; 8: Skyview RH; 9: AutoPilot; 10: ELT; 11: NAV/COM; 12: Intercom; 13: XPDR; 14: Ext. Power; 15: GPS; 16: Propeller.
It seems that some kind of sharing/grouping is inevitable to avoid devoting too much panel surface to circuit breakers. DA40 does not group devices together, and its spending of premium real estate is lavish. SR22 hides the circuit breakers in a place that a co-pilot can not reach.
Some selection of devices to group together makes sense, such as the grouping of XPDR/Encoder, while others seem random to me. For example, fuel pump operation does not seem to be related to position light or anti-collision light, and landing light is not related to RPM. What are the guidelines/principles in the selection other than total-current-should-not-trip-the-breaker? Should every device have a circuit breaker?