Electrical circuit breaker planning 5

17 hours ago

This is an update of

https://webuildplanes.com/adam-dickson-sling2/p/7098/electrical-circuit-breaker-planning-4

This version is a substantial rethink, which

eliminates all SPST switch + separate CB pairs and replaces them with W31 combined SPST/CB units
places nav and strobe lights under separate CBs
places flarm and backup efis under separate CBs
eliminates the progressive switches for the EFIS and avionics and replaces them with SPST W31 units
introduces a separate SPDT switch for the main/backup source for the above switch
introduces main bus and optional alternator CBs depending on whether I go for a firewall-forward (alternator) power feed vs panel-mount power feed. I had fixed on the former but owing to the additional room for CBs I am revisiting this question

The breaker size is matched to the smallest AWG-dependent current limit of any one branch off a given breaker or split downstream of a breaker. Current limits are taken from Table 11-3 on page 11-15 in AC43-13-1B:

22AWG - 5A
20AWG - 7.5A
18AWG -10A
16AWG - 15A
14AWG - 20A
12AWG - 30A
10AWG - 40A
8AWG - 50A
6AWG - 80A
4AWG - 100A

Breaker sizes inferred from the above table are overridden lower by any stated by Dynon, or by current limits of any interconnects

Left hand group

Bat/Alt master switch (progressive type)

"Fuel pump" switch (SPST) with integral breaker - 5A => TE W31-X2M1G-5

Right hand group

Switches (10 in all):

"MAIN/STANDBY" switch (AN3021-1 / MS35058-21 SPDT on-off-on) which can select between the main bus and backup battery output

"EFIS PWR" switch (W31 SPST 5A)

"AVIONICS PWR" switch (W31 SPST 15A)

The following are all on the "avionics" bus

radio
transponder
flarm
backup EFIS
flaps
trim

"STROBE" switch (progressive type) with positions for tail strobe only, and wing and tail strobe together and separate breaker

"TAXI" switch (16AWG 15A wire limit, 13A pin limit W31 SPST 10A)

"NAV" switch (18AWG 10A wire limit, 7.5A pin limit W31 SPST 7.5A)

"LAND" switch (progressive type) and separate breaker

"AUTO PILOT" switch (W31 SPST 7.5A)

"USB" switch (20AWG 7.5A wire limit, 7.5A pin limit W31 SPST 7.5A)

"CABIN LT" switch (progressive type) and dimmer with separate breaker

Breakers (14 in all):

"BATTERY" => Klixon 2TC2-30

"ALTERNATOR" => Klixon 2TC2-30

"STANDBY CHARGE" - IBBS charge breaker (20 AWG wire limit 7.5A) but overridden to 5A by the IBBS manual - Klixon 2TC2-5

"STANDBY OUTPUT" - IBBS backup output breaker 10A (limited so as to not exceed the 10A blade fuse and DB15 pin limits) - Klixon 2TC2-10

"LAND" breaker for the landing and taxi lights (16AWG 13A pin limit, 15A wire limit) => Klixon 2TC2-10

"STROBE" breaker 18 AWG wires, 7.5A size 20 pins shared for the strobe and nav lights => Klixon 2TC2-7.5

"COMMS" - 20AWG 7.5A overridden by Dynon schematic 5A => Klixon 2TC2-5

Com Radio control panel
Com Radio

"XPONDER" breaker 22AWG 5A overridden by Dynon schematic 3A => Klixon 2TC2-3

Transponder
ADS-B receiver

"FLARM" breaker 22AWG 5A overridden by Flarm manual 3A => Klixon 2TC2-3

Flarm fusion
Flarm trafficView80

"SEC EFIS" breaker 22AWG 5A overridden by Horis manual 1A => Klixon 2TC2-1

Kanardia Horis

"FLAPS" breaker 20AWG (7.5A wire limit) but actuator current is smaller => Klixon 2TC2-5

"CABIN" breaker 22AWG 5A wire limit, 7.5A pin limit but current draw tiny => Klixon 2TC2-1

"TRIM" breaker 22AWG - 5A wire limit but current draw small => Klixon 2TC2-2 (because a 1A popped)

"HEADSET" breaker 20AWG 5A wire limit but current draw tiny => Klixon 2TC2-1

Summary

Switches

1 x MS35058-27 (SPDT: on momentary-off-on momentary) - for flap control

1 x MS25201-4 (Eaton 8860K4) progressive switch for master

3 x MS25201-4 (Eaton 8860K4) progressive switches

1 x SPDT AN3021-1 (MS35058-21 SPDT on-off-on) switch

1 x TE W31-X2M1G-5 switch/breaker for fuel pump

1 x TE W31-X2M1G-5 switch/breaker

1 x TE W31-X2M1G-15 switch/breaker

1 x TE W31-X2M1G-10 switch/breaker

3 x TE W31-X2M1G-7.5 switch/breaker

Breakers

3 x Klixon 2TC2-1A ok

1 x Klixon 2TC2-2A ok

2 x Klixon 2TC2-3A ok

2 x Klixon 2TC2-5A 2 already ok

1 x Klixon 2TC2-7.5A ok

2 x Klixon 2TC2-10A ok

2 x Klixon 2TC2-30A ok

3 x 1A

1 x 2A

2 x 3A

2 x 5A

1 x 7.5A

2 x 10A

3 x 30A

1,2,1

5,1,3,

3,5,7.5

10,10, 5,

30, 30