Prior
to any discussion of fuses vs CBs; this issue needs some clarification.
Is it possible for more than one coil to be drawing this level of current
at the same time? I have 6 coils on my 20B; three on each circuit with a
16 AWG wire. This could be frightening!
Al
Don't
think it is a worry. All can be on for a short time (possibly long
enough to blow a fast acting fuse) but not long enough to heat a 16 ga wire
significantly.
Tracy
Tracy;
Well; the worry is this. Safe
wiring practice requires being able to protect the wire, especially if it is in
a bundle or close proximity with other wires, against any failure which would
overload the wire. Running the numbers says that the maximum safe current
for a 16 awg wire is 15 amps. If I interpret you correctly; it is
possible for my coil power lead to have to carry 27 amps (for 3 coils) for a
short time, which would trip a breaker, or blow a fuse. Under these
conditions one can not properly protect the wire against a potential short –
unless a much larger wire is used. My wires run in a wiring duct, which
isn’t exactly a bundle, but the analysis says for 27 amps in a bundle you
need about a #10 wire.
Further; I went to great lengths to
maintain the redundancy that you also strived for in the ECU with the dual controllers
and the isolation switches. I have the engine critical bus connected to
the dual battery system, and isolated by 40 amp diodes. I think you’re
suggesting that it’s possible for the coils to momentarily draw 54 amps
(6 x 9), plus pump and injectors; maybe up to nearly 70 amps. Ain’t gonna work.
So what am I misunderstanding here, or how
do we get around this? Under what temporary condition can this high
current exist? Is there an operational sequence to avoid this possible condition?
Thanks,
Al