Thanks for the explanation.
Simon
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of M.J. Gregory
Subject: RE: Europa-List: Wiring query
--> <m.j.gregory@talk21.com>
Simon,
A further point to note about Issue 4 of the circuit diagram is that the 30
amp slow blow fuses for both the battery and the alternator supply cable
protection are positioned on the firewall side as close as conveniently
possible to their power sources. This gives maximum protection to the
cables leading through to the cockpit and bus bars against the possibility
of a short circuit to ground causing them to smoke. If instead of these
fuses you have installed circuit breakers that are mounted on your panel,
then you must take particular care to ensure that you have good physical
protection for the cables leading up to them. This applies not just to your
initial installation, but to any subsequent maintenance or modification you
may do that might affect the integrity of these cables during the life of
the aircraft.
The wiring to engage the isolator is not given a fuse or circuit breaker to
protect it because it is on the ground side of the device. In contrast,
there is protection for the starter relay solenoid circuit because that is
supplying a positive to cause it to engage.
Regards
Mike
Europa Club Safety Officer
A common misconception is that fuses or circuit breakers protect devices.
Not so. The protection is for the wire, or more precisely, the insulation
on the wire. A given wire-insulation combination can carry a certain
maximum current for a specified maximum temperature increase, and circuit
protection devices are selected on this basis.
If in your example the wire is both short in length and physically protected
---From contacting anything that could make a short circuit in the event the
insulation is compromised, protection in the form of a fuse or CB is not
required.
Best regards,
Rob Housman
Europa XS Tri-Gear A070
Airframe complete
Irvine, CA
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com]On Behalf Of Simon Smith
Subject: Europa-List: Wiring query
Hi all,
I have virtually completed the wiring in accordance with the diagram on
Page 25-11 issue 4 which I believe is the latest version. I am using a
battery isolator and, after discussion with Andy, I have swapped the 30amp
slow blow fuses on the battery feed and regulator feed to 25 amp CB's.
I crossed my fingers and powered it up and fortunately everything seems to
work. One thing that I have noticed though is that if the batt master CB is
pulled, power is removed from the aircraft but the isolator remains
energised (which I think is correct according to the diagram). Does it
matter that there is no fuse/cb protecting the isolator?
Cheers
Simon
#504 G-BZTN
80% done 90% left to do!
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