I'm a bit confused with the current wiring in my boat. I've stripped
everything out except for the gauges and the ignition, as I'll be installing
new wiring for all the switches and accessories. My goal at the moment is
to install a fuse block and a negative bus bar. This all takes place in a
1970 Century Resorter, and the existing wiring was obviously "modified"
during the various projects of previous owners.

Lead Up Question #1
I'm confused on how the Battery, Alternator, Amp Meter and Ignition are
wired. There are three terminals on the back of the amp meter: [Wire to
Battery Ground], [Wire to Battery Positive], [Two Wires: 1 from Alternator
and 1 to Ignition]. The wire to the ignition is the "hot feed" to the
ignition. It's always on even when the Alternator is not producing power.
It appears that the two positive terminals on the back of the amp meter (one
from positive battery the other from alternator) are both always hot. Are
these simply common terminals?

Lead Up Question #2
The positive lead that goes from the battery to the amp meter is split by a
small cylinder "thingy" mounted behind the dash board with a "40" on it. Is
this likely a master 40 Amp Fuse?

The Main Question
How should the new Fuse Block be wired in? Where should it exist in
relation to the wires described above?

Unrelated "What the heck?" Question
My stern light has a positive lead coming from it's switch. The negative
lead is terminated on the gas tank's sender unit (a perimeter screw, not the
center screw which I assume is the "sender"). As far as I know, the gas
tank is not grounded to the engine or the battery. The only other wire
coming out of the sender unit goes directly to the Fuel Gauge. Is the light
grounded to the fuel tank?

Unrelated Garble...
I've greatly appreciated the great responses I've received from this
newsgroup over the past couple of months during my never-ending project.
It's truly been a great resource. Thanks to everyone that makes this a
worthwhile newsgroup!

Doug

Correction on terms... what I was referring to as an Amp Meter is actually a
"Zero Center DC Ammeter", similar in appearance to...
http://www.bluesea.com/Products/small_images/8252.jpg

Here's the installation diagram for this product...
http://www.bluesea.com/Instruction/9878.pdf

It looks like my installation is similar to (but not wired the same way) as
gauge #2. Is it possible a gauge from 1970 would have a built in "shunt"?

Thanks Again!

"Douglas St. Clair" wrote in message
...
I'm a bit confused with the current wiring in my boat. I've stripped
everything out except for the gauges and the ignition, as I'll be
installing
new wiring for all the switches and accessories. My goal at the moment is
to install a fuse block and a negative bus bar. This all takes place in a
1970 Century Resorter, and the existing wiring was obviously "modified"
during the various projects of previous owners.

Lead Up Question #1
I'm confused on how the Battery, Alternator, Amp Meter and Ignition are
wired. There are three terminals on the back of the amp meter: [Wire to
Battery Ground], [Wire to Battery Positive], [Two Wires: 1 from Alternator
and 1 to Ignition]. The wire to the ignition is the "hot feed" to the
ignition. It's always on even when the Alternator is not producing power.
It appears that the two positive terminals on the back of the amp meter
(one
from positive battery the other from alternator) are both always hot. Are
these simply common terminals?

Lead Up Question #2
The positive lead that goes from the battery to the amp meter is split by
a
small cylinder "thingy" mounted behind the dash board with a "40" on it.
Is
this likely a master 40 Amp Fuse?

The Main Question
How should the new Fuse Block be wired in? Where should it exist in
relation to the wires described above?

Unrelated "What the heck?" Question
My stern light has a positive lead coming from it's switch. The negative
lead is terminated on the gas tank's sender unit (a perimeter screw, not
the
center screw which I assume is the "sender"). As far as I know, the gas
tank is not grounded to the engine or the battery. The only other wire
coming out of the sender unit goes directly to the Fuel Gauge. Is the
light
grounded to the fuel tank?

Unrelated Garble...
I've greatly appreciated the great responses I've received from this
newsgroup over the past couple of months during my never-ending project.
It's truly been a great resource. Thanks to everyone that makes this a
worthwhile newsgroup!

Doug

Doug,

I rewired my 1958 Chris Craft last year. I asked lots of questions, learned
some things, and everything appears to be fine. But please double check my
answers since, especially when it comes to the heavy current going through
the ammeter, that wiring it wrong could produce serious problems & hazzards.


Lead Up Question #1
There are three terminals on the back of the amp meter:
[Wire to Battery Ground], [Wire to Battery Positive],
[Two Wires: 1 from Alternator and 1 to Ignition].

If your ammmeter is lighted by a bulb then I think the wire going
to battery ground is just to provide ground for that bulb. If so, it
is probably a smaller wier than the larger positive wires. Probably
16 gauge? ~~ Also, some ammeters have an external shunt. I
don't know how those work/are configured. ???

I think the positive wire to your key is just a place for the key to get
power. I'm guessing that someplace coming out of the key is a wire
going to all the "accessory" power items. This is OK in that all of those
items are then controlled by the key. But it also means that all of their
draw is going through the key. This is OK but I choose to do
it differently. (see below)

The positive to battery and to altenator make sense. Power is
being produced by the altenator, flowing through the ammeter
(making it show positivly), and to the battery. OR power is flowing
from the battery, through the ammeter the other way (making it
show negativly) and then to the KEY for use by all the accessories.

In short: What you describe is fine & makes sense.



Lead Up Question #2
The positive lead that goes from the battery to the amp meter is split by
a
small cylinder "thingy" mounted behind the dash board with a "40" on it.
Is
this likely a master 40 Amp Fuse?


That's my guess.


The Main Question
How should the new Fuse Block be wired in? Where should it exist in
relation to the wires described above?


What I did is a little different than some of what you have above. It may be
a good solution for you...or not. I also have a diagram I'd be happy to send
you
(or maybe I'll just post it on the web and leave you a link in a little
while).
My setup:

A) I have two batteries. They are connected to an A/B switch. The details
of this are for another discussion. But when I say "from the battery"
it
really is coming from the A/B switch.

B) A large 10 gague red wire comes from the battery positive, through a
fuse, and to the "S" post on the ammeter.

C) A large 10 gague red wire comes from the ammeter "I" post to the
positive bus on my fuse panel.

D) All accessories like lights, dash-board instrumentation, depth-finder,
12-volt outlets, etc. come from the "fused" side of the fuse panel.
That
is to say, the current comes from the positive bus, through a fuse,
and
out to each device.

E) The same goes for my ignition key. That is, there is the positive bus
on the fuse panel, a fused lead, and that goes to the key.

Note: This means my key does NOT turn on or off any devices. It
only gets power to run the starter-solnoid and to give the engine
"spark" to the coil. I realize that most people like to have items
turned on and off via the key. I choose to turn them on or off via
their own switches and/or to have a fuse panel that has switches
in it.

D) There is a large 10 gague Orange wire from my voltage regulator
(your altenator) that goes through a fuse and to the same positive
fuse-panel bus.

THE GENERAL IDEA IS:
Power flows from the battery, through the ammeter, and into the positvie
fuse-panel-bus. Power also flows from the ammeter to this positive-fuse
panel-bus. Some power is used from this bus to run all of the accessoris
and the key. ~~ When the engine if off all the power is coming from the
battery and shows as a negative amps. When the engine is on there is
"excess" power on the fuse panel bus and this flow through the ammeter
and to the battery - showing positive amps on the ammeter.

Note #1: Above I say "large 10 gague". I know this is redundant but it's
important that the wires are big ones and I wanted to emphisize that.

Note #2: I'm sure my colors are not standard. I wanted to have RED
be from the battery since that is how I think of it. I also wanted
the positive power form the regulator (altenator) be a different color wire.
Orange is what the store had in 10 gague when I went to buy it.




Unrelated "What the heck?" Question
My stern light has a positive lead coming from it's switch. The negative
lead is terminated on the gas tank's sender unit.

The gas tank SHOULD be grounded to some metal (probably the engine)
that has a path to the water. If you ground the tank I can't see any reason
not to let the stern light ground through there. Except that you want it to
be
a good solid connection with no chance of a spark jumping from wire to tank.

But also no reason you couldn't run a seperate ground wire (or wire pair)
back
to your stern light.


I've greatly appreciated the great responses I've received from this
newsgroup over the past couple of months during my never-ending project.
It's truly been a great resource. Thanks to everyone that makes this a
worthwhile newsgroup!


I agree. This group has a lot of politics and non-boat junk (which I am
guilty
of adding to) but whenever someone needs information this is a great place
to ask for it. Lots of people here with knowledge that are willing to take
time to share it.

I'll post my wiring diagram in a little while and then leave a link here.

Good Luck.

Gary

Here's a link to my wiring diagram:

http://tinyurl.com/yqud3

Thanks Gary!

What you described makes perfect sense. I printed out your post and took it
out to the boat for comparison. The only difference I found is that the
wire from my alternator is not fused prior to the ammeter. Should I put one
in? If so, what amperage?

I'll be hooking up my fuse panel the same way. I'll run the ignition
through it's own fuse on the panel. How do you pick the proper fuse for
such a setup? What type of draw does the ignition have - solenoid + gauges
+ ?

Thanks again -
Doug



"Gary Warner" wrote in message
...

Here's a link to my wiring diagram:

http://tinyurl.com/yqud3

"Douglas St. Clair" wrote in message
...
Thanks Gary!

What you described makes perfect sense. I printed out your post and took
it
out to the boat for comparison. The only difference I found is that the
wire from my alternator is not fused prior to the ammeter. Should I put
one
in? If so, what amperage?


I don't think a fuse is required there. I just decided to do it on the "what
can it hurt" theory. I really don't know what size fuse to use there.
That's
a question I have myself.

Gary Warner wrote:


"Douglas St. Clair" wrote in message
...
Thanks Gary!

What you described makes perfect sense. I printed out your post and took
it
out to the boat for comparison. The only difference I found is that the
wire from my alternator is not fused prior to the ammeter. Should I put
one
in? If so, what amperage?


I don't think a fuse is required there. I just decided to do it on the
"what
can it hurt" theory. I really don't know what size fuse to use there.
That's
a question I have myself.

Normally that is the reason for a "fuselink" from the battery positive post.
It's not the amps that are put out from the alternator that cause the damage
of a short, it's the amperage potental of the battery that needs
disconnected quickly by blowing the fuselink open at the battery.

--
__________m___~¿Ô___m____________________________

"____m___~¿Ô___m____" wrote in message
news:%TEfc.33606

Normally that is the reason for a "fuselink" from the battery positive
post.
It's not the amps that are put out from the alternator that cause the
damage
of a short, it's the amperage potental of the battery that needs
disconnected quickly by blowing the fuselink open at the battery.


I don't understand what you mean by amperage potential of the battery. Do
you
mean the power is it capable of delivering TO the fuse panel if there was
ever
some big draw there (like a short) ??

"Gary Warner" wrote in message
...


The only difference I found is that the
wire from my alternator is not fused prior to the ammeter. Should I put
one in? If so, what amperage?

In general, the fuse/circuit breaker should be sized appropriately to
protect the wiring, not any device on the circuit. The wire should be sized
so that it can carry the maximum output of the alternator with a comfortable
margin. The fuse should be sized so that the fuse blows if the current
should exceed the rating of the wire. You can do a web search to find
tables that provide wire size vs. current capacity.




I don't think a fuse is required there. I just decided to do it on the
"what
can it hurt" theory.


Well, one thing that it can hurt is the alternator!

Fuses can fatigue and fail without their ratings ever being exceeded. If
the fuse opens while the alternator is running at full output and leaves the
alternator disconnected from any load there is a high probability that the
resulting voltage spike will destroy the diodes in the alternator.

Rod

"Rod McInnis" wrote in message
...

. The fuse should be sized so that the fuse blows if the current
should exceed the rating of the wire. You can do a web search to find
tables that provide wire size vs. current capacity.


Now that makes sense. Thanks.