My boat has non-standard color coding on the AC wiring, typically all
3 wires red instead of the US standard of black, white, green.

Identifying the hot wire is easy but I'm not sure how to positively
identify the neutral wire vs the safety ground. Measuring voltage
from the hot wire yields 110 to either one. This is looking from the
load end not the panel end of course.

Anyone have suggestions?

Wayne.B wrote:
:My boat has non-standard color coding on the AC wiring, typically all
:3 wires red instead of the US standard of black, white, green.

:Identifying the hot wire is easy but I'm not sure how to positively
:identify the neutral wire vs the safety ground. Measuring voltage
:from the hot wire yields 110 to either one. This is looking from the
:load end not the panel end of course.

:Anyone have suggestions?

Besides replace the wiring with something sane? Get a tone generator
and receiver. You put the tone generator at a known end of the wire.
It puts an RF signal on the wire, which you detect with the receiver.
You should be able to find one locally for about $50 or so.

David Scheidt wrote:
Wayne.B wrote:
:My boat has non-standard color coding on the AC wiring, typically all
:3 wires red instead of the US standard of black, white, green.

:Identifying the hot wire is easy but I'm not sure how to positively
:identify the neutral wire vs the safety ground. Measuring voltage
:from the hot wire yields 110 to either one. This is looking from the
:load end not the panel end of course.

:Anyone have suggestions?

Besides replace the wiring with something sane? Get a tone generator
and receiver. You put the tone generator at a known end of the wire.
It puts an RF signal on the wire, which you detect with the receiver.
You should be able to find one locally for about $50 or so.

Well, the tone generator is one
approach. I assume you don't have an
isolation transformer. If you did, then
the neutral and ground wires would be
bonded at the transformer secondary and
you'd never figure out which is which.

Goes without saying that you should
disconnect the shore power cable before
feeling about. Sanely wired boats do not
have the neutral and ground bonded
onboard the boat. They are connected
back at the marina's entrance panel.

So you can use an ohmmeter, continuity
tester, battery and light bulb, etc., or
a tone generator to determine which red
wire goes to the ground pin on the shore
power connector. Or if you harbor a
proclivity for neutrality, you could
track down the neutral instead.

Another technique (assuming your boat is
actually wired for AC with receptacles,
etc., is to use one of the "polarity
testers" that plug into the outlets.
They cost a few dollars and will tell
you if the receptacle is miswired and if
so, how.

Short of rewiring, which certainly has
its merits, buy a roll of green tape and
white tape and as you identify ground
and neutral, place a dab of tape on the
wire.

Good luck.

Chuck

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"Wayne.B" wrote:

My boat has non-standard color coding on the AC wiring, typically all
3 wires red instead of the US standard of black, white, green.

Identifying the hot wire is easy but I'm not sure how to positively
identify the neutral wire vs the safety ground. Measuring voltage
from the hot wire yields 110 to either one. This is looking from the
load end not the panel end of course.

Anyone have suggestions?

Turn on some loads and measure the return current in each conductor at 0
volts. The neutral should have the same current as the hot. The ground
should carry no current.

But, I'm willing to bet that the ground/neutrals have been mixed up
between junctions and you will see some current on each.

The only way to know for sure is to disconnect each run of wiring
between junction boxes or splices and use a continuity tester.

P.S. Mark everything with appropriate colored tape as you identify it.

--
Paul Hovnanian
------------------------------------------------------------------
Trust the computer industry to shorten the term "Year 2000" to Y2K.
It was this kind of thinking that got us in trouble in the first place.
-- Adrian Tyvand

On Mon, 21 May 2007 14:44:10 -0400, Wayne.B
wrote:

My boat has non-standard color coding on the AC wiring, typically all
3 wires red instead of the US standard of black, white, green.

Identifying the hot wire is easy but I'm not sure how to positively
identify the neutral wire vs the safety ground. Measuring voltage
from the hot wire yields 110 to either one. This is looking from the
load end not the panel end of course.

Anyone have suggestions?

Neutral and Ground should not be connected on-board. (although if the
boat is wired with all red wires, there's no telling what strange
things may be going on...)

Disconnect the boat from shore power, and use an ohmmeter to check for
continuity between the Ground pin on the shore power cable and the
unknown wires. (If the boat has an inverter, make certain that it is
disabled while doing _any_ work on the 120VAC system!)


--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca

On Mon, 21 May 2007 18:16:26 -0700, Peter Bennett
wrote:

Disconnect the boat from shore power, and use an ohmmeter to check for
continuity between the Ground pin on the shore power cable and the
unknown wires. (If the boat has an inverter, make certain that it is
disabled while doing _any_ work on the 120VAC system!)

Thanks.

I think you meant to say the shore power connector (as opposed to the
cord) if I'm understanding your advice correctly.

Wayne.B wrote in
:

Anyone have suggestions?


We could unplug the dock end and drag it into the boat's power panel. The
ground pin on the dock plug is plainly marked. It's L shaped. Just use an
ohmmeter or even a continuity light that's battery powered to find the
right one.



Larry
--
Grade School Physics Factoid:
A building cannot freefall into its own footprint without
skilled demolition.

On Tue, 22 May 2007 02:54:15 +0000, Larry wrote:

We could unplug the dock end and drag it into the boat's power panel. The
ground pin on the dock plug is plainly marked. It's L shaped. Just use an
ohmmeter or even a continuity light that's battery powered to find the
right one.

I like that suggestion. The shore power cable is long enough to
easily reach to where I need to do the testing. Let's hope that
neutral and ground are not tied together somewhere.

On Tue, 22 May 2007 02:54:15 +0000, Larry wrote:

The
ground pin on the dock plug is plainly marked. It's L shaped.

It turns out that the L shaped pin is ground only on the 20 and 30 amp
connectors. On a 50 amp connector it is neutral:

http://www.marinco.com/docs/guides/Boater'sGuidetoACElectrical.pdf

On Mon, 21 May 2007 22:40:34 -0400, Wayne.B
wrote:

On Mon, 21 May 2007 18:16:26 -0700, Peter Bennett
wrote:

Disconnect the boat from shore power, and use an ohmmeter to check for
continuity between the Ground pin on the shore power cable and the
unknown wires. (If the boat has an inverter, make certain that it is
disabled while doing _any_ work on the 120VAC system!)

Thanks.

I think you meant to say the shore power connector (as opposed to the
cord) if I'm understanding your advice correctly.

Either one - it is probably easier to get the shore end of the cord
near your mystery wires than to stretch the meter leads between the
mystery wires and the shore power connector.


--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
new newsgroup users info : http://vancouver-webpages.com/nnq
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca