Re: Combining AC and DC grounds

Posted by Michel Capel (mike_c_f35ck@…>)

In The Marine Electrical and Electronics Bible by John C. Payne (ed
1994), on page 236 he says: Combining AC ground and DC neutral is
criminal. The basic physics of the two systems (230/115V AC and
12/24V DC) are different and unrelated.
There is no technical validity in this (he dismantles 4 popular and
wrong beliefs on the next page) and you run the risk that the whole
boat becomes ‘hot’(electrified) when there is an AC fault going to
ground. His opinion is based on US, UK, European and Australian
standards for Marine Electrics.

Michel Capel


— In freedomyachts2003@yahoogroups.com, “macks011” <macks04@o…>
wrote:

There is a ongoing debate about this. The American YBC says
combine
them. The Brits say split them. Combining reduces further the
potential of shock. Splitting reduces further the potential for
electrolysis. There are compelling arguments for both sides of the
question. It becomes a perceived risk issue. AYBC makes the
assessment and places perceived safety over electrolysis risk,
knowing full well the choice.

A simple desire to clean up the rats nest behind my elec. panel
seems to be headed towards an enforced graduate program in marine
elec. systems.

I can see where my previous post was possibly unclear.The post you
are responding to addresses an AC safety problem in
combined AC/DC panels whether or not you combine or seperate the
AC
ground/DC negative. I am removing the possibility of shock or
short
by moving the AC neutrals off the panel to a remote location,
shielding the bus from contact, and shielding the AC breakers on
the
panel.

I still haven’t made the choice to connect or disconnect the AC
ground /DC negative yet, but now its a simple 30 second
task to connect or disconnect a wire.

— In freedomyachts2003@yahoogroups.com, “Dave_Benjamin”
<dave_benjamin@y…> wrote:

What was the rationale for separating the AC neutral and DC
ground?
What was the risk? I think Calder or one of the other techie
types
talks about this in one of the books. I’ll have time next week
to
do
some reading up. The reason I’m bringing it up is I think that
there
are some compelling reasons for leaving the ground and neutral
common
but I could be wrong.

— In freedomyachts2003@yahoogroups.com, “macks011”
<macks04@o…> wrote:

Not long ago, there was a discussion about wiring the elec.
panel
and one of the respondents brought up the issue of segregating
the
AC from the DC. for safety reasons. On the face of it, it
would
seem
difficult to seperate AC from DC on a common panel, but there
is
an
easy solution.

  1. replace the common ground bus with a double bus (Blue Sea #
  1. run all your grounds common to one side and all the
    neutrals
    to
    the other.
  2. Remove the short run that connects the main neutral to the
    neutral panel bus and run a leg instead to the off panel bus.
  3. Cover the off panel bus with a small piece of scrap plexi
    and
    do
    the same over the breakers by wiretying a piece of plexi to
    the
    positive leads.

The on panel neutral bus is now in-active and the posi leads
are
shielded. $25.00 crimps, wire, bus and plexi.

Posted by macks011 (macks04@…>)

Yet, if you brought your boat over here, it wouldn’t pass a survey.
Go figure.


— In freedomyachts2003@yahoogroups.com, “Michel Capel”
<mike_c_f35ck@y…> wrote:

In The Marine Electrical and Electronics Bible by John C. Payne
(ed
1994), on page 236 he says: Combining AC ground and DC neutral is
criminal. The basic physics of the two systems (230/115V AC and
12/24V DC) are different and unrelated.
There is no technical validity in this (he dismantles 4 popular
and
wrong beliefs on the next page) and you run the risk that the
whole
boat becomes ‘hot’(electrified) when there is an AC fault going to
ground. His opinion is based on US, UK, European and Australian
standards for Marine Electrics.

Michel Capel

— In freedomyachts2003@yahoogroups.com, “macks011”
<macks04@o…>
wrote:

There is a ongoing debate about this. The American YBC says
combine
them. The Brits say split them. Combining reduces further the
potential of shock. Splitting reduces further the potential for
electrolysis. There are compelling arguments for both sides of
the
question. It becomes a perceived risk issue. AYBC makes the
assessment and places perceived safety over electrolysis risk,
knowing full well the choice.

A simple desire to clean up the rats nest behind my elec. panel
seems to be headed towards an enforced graduate program in
marine
elec. systems.

I can see where my previous post was possibly unclear.The post
you
are responding to addresses an AC safety problem in
combined AC/DC panels whether or not you combine or seperate the
AC
ground/DC negative. I am removing the possibility of shock or
short
by moving the AC neutrals off the panel to a remote location,
shielding the bus from contact, and shielding the AC breakers on
the
panel.

I still haven’t made the choice to connect or disconnect the AC
ground /DC negative yet, but now its a simple 30 second
task to connect or disconnect a wire.

— In freedomyachts2003@yahoogroups.com, “Dave_Benjamin”
<dave_benjamin@y…> wrote:

What was the rationale for separating the AC neutral and DC
ground?
What was the risk? I think Calder or one of the other techie
types
talks about this in one of the books. I’ll have time next week
to
do
some reading up. The reason I’m bringing it up is I think that
there
are some compelling reasons for leaving the ground and neutral
common
but I could be wrong.

— In freedomyachts2003@yahoogroups.com, “macks011”
<macks04@o…> wrote:

Not long ago, there was a discussion about wiring the elec.
panel
and one of the respondents brought up the issue of
segregating
the
AC from the DC. for safety reasons. On the face of it, it
would
seem
difficult to seperate AC from DC on a common panel, but
there
is
an
easy solution.

  1. replace the common ground bus with a double bus (Blue Sea

  1. run all your grounds common to one side and all the
    neutrals
    to
    the other.
  2. Remove the short run that connects the main neutral to
    the
    neutral panel bus and run a leg instead to the off panel
    bus.
  3. Cover the off panel bus with a small piece of scrap plexi
    and
    do
    the same over the breakers by wiretying a piece of plexi to
    the
    positive leads.

The on panel neutral bus is now in-active and the posi leads
are
shielded. $25.00 crimps, wire, bus and plexi.

Posted by Paul McFadden (pwhitmac@…>)
I happen to agree with Mr. Payne, unfortunately, the ABYC doesn’t. I guess they presuppose that ALL dock wiring is suspect, and they are heavily invested in the Zinc industry (joke) PWMMichel Capel <mike_c_f35ck@…> wrote: In The Marine Electrical and Electronics Bible by John C. Payne (ed 1994), on page 236 he says: Combining AC ground and DC neutral is criminal. The basic physics of the two systems (230/115V AC and 12/24V DC) are different and unrelated. There is no technical validity in this (he dismantles 4 popular and wrong beliefs on the next page) and you run the risk that the whole boat becomes ‘hot’(electrified) when there is an AC fault going to ground. His opinion is based on US, UK, European and Australian standards for Marine Electrics.Michel Capel— In
freedomyachts2003@yahoogroups.com, “macks011” <macks04@o…> wrote:>> There is a ongoing debate about this. The American YBC says combine > them. The Brits say split them. Combining reduces further the > potential of shock. Splitting reduces further the potential for > electrolysis. There are compelling arguments for both sides of the > question. It becomes a perceived risk issue. AYBC makes the > assessment and places perceived safety over electrolysis risk, > knowing full well the choice.> > A simple desire to clean up the rats nest behind my elec. panel > seems to be headed towards an enforced graduate program in marine > elec. systems. > > I can see where my previous post was possibly unclear.The post you > are responding to addresses an AC safety problem in > combined AC/DC panels whether or not you combine or seperate the AC > ground/DC
negative. I am removing the possibility of shock or short > by moving the AC neutrals off the panel to a remote location, > shielding the bus from contact, and shielding the AC breakers on the > panel.> > I still haven’t made the choice to connect or disconnect the AC > ground /DC negative yet, but now its a simple 30 second > task to connect or disconnect a wire.> > > > — In freedomyachts2003@yahoogroups.com, “Dave_Benjamin” > <dave_benjamin@y…> wrote:> >> > What was the rationale for separating the AC neutral and DC ground?> > What was the risk? I think Calder or one of the other techie types> > talks about this in one of the books. I’ll have time next week to > do> > some reading up. The reason I’m bringing it up is I think that > there> > are some compelling reasons for leaving the ground and
neutral > common> > but I could be wrong.> > > > — In freedomyachts2003@yahoogroups.com, “macks011” > <macks04@o…> wrote:> > >> > > Not long ago, there was a discussion about wiring the elec. > panel > > > and one of the respondents brought up the issue of segregating > the > > > AC from the DC. for safety reasons. On the face of it, it would > seem > > > difficult to seperate AC from DC on a common panel, but there is > an > > > easy solution. > > > > > > 1. replace the common ground bus with a double bus (Blue Sea # > 2700)> > > 2. run all your grounds common to one side and all the neutrals > to > > > the other.> > > 3. Remove the short run that connects the main neutral to the > > > neutral panel bus and run a leg
instead to the off panel bus.> > > 4. Cover the off panel bus with a small piece of scrap plexi and > do > > > the same over the breakers by wiretying a piece of plexi to the > > > positive leads.> > > > > > The on panel neutral bus is now in-active and the posi leads are > > > shielded. $25.00 crimps, wire, bus and plexi.> > >> >>
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Posted by Dave_Benjamin (dave_benjamin@…>)

I hear the ABYC plans to recommend isolation transformers as standard
equipment. Personally I see this as a great thing. Although it will
raise the cost of new boats that most of us aren’t going to buy
anyway it will spur production of isolation transformers and get the
prices down.

I read a review of a new Hunter and was shocked (no pun intended) to
find that they include an isolation transformer as standard
equipment. An isolation transformer is the way to go but they are
rather heavy, expensive, and bulky. It’s great if you’re cruising
though.


— In freedomyachts2003@yahoogroups.com, Paul McFadden
<pwhitmac@y…> wrote:

I happen to agree with Mr. Payne, unfortunately, the ABYC doesn’t.
I guess they presuppose that ALL dock wiring is suspect, and they are
heavily invested in the Zinc industry (joke)
PWM

Posted by macks011 (macks04@…>)

Iso transformers are the way to go, but, they are noisy, give off
heat and are not suitable for smaller boats. I think I am going to
experiment this season and break the AC ground/DC negative
connection. The majority of the time I am connected to a known AC
source. There is no reason why I can’t test the source with a 30
amp/15amp adapter and a Home Depot plug-in ground tester before
connecting the boat.





In freedomyachts2003@yahoogroups.com, “Dave_Benjamin”
<dave_benjamin@y…> wrote:

I hear the ABYC plans to recommend isolation transformers as
standard
equipment. Personally I see this as a great thing. Although it
will
raise the cost of new boats that most of us aren’t going to buy
anyway it will spur production of isolation transformers and get
the
prices down.

I read a review of a new Hunter and was shocked (no pun intended)
to
find that they include an isolation transformer as standard
equipment. An isolation transformer is the way to go but they are
rather heavy, expensive, and bulky. It’s great if you’re cruising
though.

— In freedomyachts2003@yahoogroups.com, Paul McFadden
<pwhitmac@y…> wrote:

I happen to agree with Mr. Payne, unfortunately, the ABYC
doesn’t.
I guess they presuppose that ALL dock wiring is suspect, and they
are
heavily invested in the Zinc industry (joke)
PWM

Posted by Dave_Benjamin (dave_benjamin@…>)

— In freedomyachts2003@yahoogroups.com, “macks011” <macks04@o…> wrote:

Iso transformers are the way to go, but, they are noisy, give off
heat and are not suitable for smaller boats. I think I am going to
experiment this season and break the AC ground/DC negative
connection.

Something tells me that if isolation transformers become mandated they
will become quieter, smaller, and less expensive. At least I hope they
will. We looked at installing one on Entropy.

One inexpensive form of protection is a galvanic isolator that will
disconnect the AC neutral if it starts carrying current.

Posted by macks011 (macks04@…>)

You may have a different style of galvanic isolator, but mine is
connected to the shore power ground only, immediately after the
shorepower socket. http://www.yandina.com/acrobats/GalvOwnManual.pdf






. — In freedomyachts2003@yahoogroups.com, “Dave_Benjamin”
<dave_benjamin@y…> wrote:

One inexpensive form of protection is a galvanic isolator that will
disconnect the AC neutral if it starts carrying current.

Posted by Brian Guptil (sailordude@…>)


Galvanic Isolators
Gentlemen
I hope that
no-one has a galvanic isolator that “disconnects” the safety when current
starts to flow because the current path to ground IS the SAFETY.
What they do is
“block” very low voltages, in the neighborhood of 1.5V or
less. These voltages are where galvanic activity takes place. But
when the voltages get above that, safety becomes the issue and thus the “Isolator”
passes any current that causes more then 1.5V to appear across the “Isolator”.
These devices
are typically mad up of 4, high current (like 50Amp), silicon diodes wired, two
in series in one direction and two in series in the opposite direction. Thus
two of then are always forward biased.

If zincs are disappearing
faster then a set in 4 to 6 months, then something is wrong and could be that
the safety ground lead coming down the dock is elevated (electrically)for some
reason, like defective equipment on someone’s boat.

Brian
Guptil sailordude@…
2501 Boston St.
Slip-36 www.brigup.com
Baltimore, MD
21224 206-818-3203
S/V Cayenne is
moored on C dock.

-----Original Message-----
From: freedomyachts2003@yahoogroups.com [mailto:freedomyachts2003@yahoogroups.com] On Behalf Of macks011
Sent: Tuesday, January 24, 2006 10:02 AM
To: freedomyachts2003@yahoogroups.com
Subject: [freedomyachts2003] Re:
Combining AC and DC grounds

You may have a different style of galvanic isolator,
but mine is
connected to the shore power ground only,
immediately after the
shorepower socket. http://www.yandina.com/acrobats/GalvOwnManual.pdf






. — In freedomyachts2003@yahoogroups.com,
“Dave_Benjamin”
<dave_benjamin@y…> wrote:

One inexpensive form of protection is a
galvanic isolator that will
disconnect the AC neutral if it starts
carrying current.






\

Posted by Dave_Benjamin (dave_benjamin@…>)

That is exactly what I was referring to. The isolator is connected
only to the shorepower neutral (green wire typically) right where it
enters the boat. The galvanic isolator is a low cost method of
preventing stray current induced corrosion. It also provides some
safety for a diver or swimmer in the water.


— In freedomyachts2003@yahoogroups.com, “macks011” <macks04@o…>
wrote:

You may have a different style of galvanic isolator, but mine is
connected to the shore power ground only, immediately after the
shorepower socket. http://www.yandina.com/acrobats/GalvOwnManual.pdf

. — In freedomyachts2003@yahoogroups.com, “Dave_Benjamin”
<dave_benjamin@y…> wrote:

One inexpensive form of protection is a galvanic isolator that
will
disconnect the AC neutral if it starts carrying current.

Posted by Michel Capel (mike_c_f35ck@…>)

I just read that in a 110 v system, green is ground or earth, black
ia positive or hot and white is neutral. Am I mixed up?


— In freedomyachts2003@yahoogroups.com, “Dave_Benjamin”
<dave_benjamin@y…> wrote:

That is exactly what I was referring to. The isolator is connected
only to the shorepower neutral (green wire typically) right where
it
enters the boat. The galvanic isolator is a low cost method of
preventing stray current induced corrosion. It also provides some
safety for a diver or swimmer in the water.

— In freedomyachts2003@yahoogroups.com, “macks011”
<macks04@o…>
wrote:

You may have a different style of galvanic isolator, but mine is
connected to the shore power ground only, immediately after the
shorepower socket.
http://www.yandina.com/acrobats/GalvOwnManual.pdf

. — In freedomyachts2003@yahoogroups.com, “Dave_Benjamin”
<dave_benjamin@y…> wrote:

One inexpensive form of protection is a galvanic isolator that
will
disconnect the AC neutral if it starts carrying current.

Posted by Lorman, Alvin J. (ajlorman@…>)

No.

-----Original Message-----From: freedomyachts2003@yahoogroups.com [mailto:freedomyachts2003@yahoogroups.com] On Behalf Of Michel CapelSent: Tuesday, January 24, 2006 3:07 PMTo: freedomyachts2003@yahoogroups.comSubject: [freedomyachts2003] Re: Combining AC and DC groundsI just read that in a 110 v system, green is ground or earth, black ia positive or hot and white is neutral. Am I mixed up?— In freedomyachts2003@yahoogroups.com, “Dave_Benjamin” <dave_benjamin@y…> wrote:>> That is exactly what I was referring to. The isolator is connected > only to the shorepower neutral (green wire typically) right where it > enters the boat. The galvanic isolator is a low cost method of > preventing stray current induced corrosion. It also provides some > safety for a diver or swimmer in the water. > > > — In freedomyachts2003@yahoogroups.com, “macks011” <macks04@o…> > wrote:> >> > You may have a different style of galvanic isolator, but mine is > > connected to the shore power ground only, immediately after the > > shorepower socket. http://www.yandina.com/acrobats/GalvOwnManual.pdf> > > > > > > > > > > > > > . — In freedomyachts2003@yahoogroups.com, “Dave_Benjamin” > > <dave_benjamin@y…> wrote:> > >> > > > > > One inexpensive form of protection is a galvanic isolator that > will> > > disconnect the AC neutral if it starts carrying current.> > >> >>
=00IRS CIRCULAR 230 NOTICE. Any advice expressed above as to tax matters was neither written nor intended by the sender or Mayer, Brown, Rowe Maw LLP to be used and cannot be used by any taxpayer for the purpose of avoiding tax penalties that may be imposed under U.S. tax law. If any person uses or refers to any such tax advice in promoting, marketing or recommending a partnership or other entity, investment plan or arrangement to any taxpayer, then (i) the advice was written to support the promotion or marketing (by a person other than Mayer, Brown, Rowe Maw LLP) of that transaction or matter, and (ii) such taxpayer should seek advice based on the taxpayers particular circumstances from an independent tax advisorThis email and any files transmitted with it are intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. If you are not the named addressee you should not disseminate, distribute or copy this e-mail.

Posted by Dave_Benjamin (dave_benjamin@…>)

There was an error in my post. I’ve actually referred to the AC ground
as neutral. Luckily when I’ve installed isolators they’ve gone on the
green ground wire and not a neutral wire.

— In freedomyachts2003@yahoogroups.com, “Lorman, Alvin J.”
<ajlorman@y…> wrote:

No.

-----Original Message-----
From: freedomyachts2003@yahoogroups.com
[mailto:freedomyachts2003@yahoogroups.com] On Behalf Of Michel Capel
Sent: Tuesday, January 24, 2006 3:07 PM
To: freedomyachts2003@yahoogroups.com
Subject: [freedomyachts2003] Re: Combining AC and DC grounds

I just read that in a 110 v system, green is ground or earth, black
ia positive or hot and white is neutral. Am I mixed up?

— In freedomyachts2003@yahoogroups.com, “Dave_Benjamin”
<dave_benjamin@y…> wrote:

That is exactly what I was referring to. The isolator is connected
only to the shorepower neutral (green wire typically) right where
it
enters the boat. The galvanic isolator is a low cost method of
preventing stray current induced corrosion. It also provides some
safety for a diver or swimmer in the water.

— In freedomyachts2003@yahoogroups.com, “macks011”
<macks04@o…>
wrote:

You may have a different style of galvanic isolator, but mine is
connected to the shore power ground only, immediately after the
shorepower socket.
http://www.yandina.com/acrobats/GalvOwnManual.pdf

. — In freedomyachts2003@yahoogroups.com, “Dave_Benjamin”
<dave_benjamin@y…> wrote:

One inexpensive form of protection is a galvanic isolator that
will
disconnect the AC neutral if it starts carrying current.

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IRS CIRCULAR 230 NOTICE. Any advice expressed above as to tax
matters was neither written nor intended by the sender or Mayer,
Brown, Rowe & Maw LLP to be used and cannot be used by any taxpayer
for the purpose of avoiding tax penalties that may be imposed under
U.S. tax law. If any person uses or refers to any such tax advice in
promoting, marketing or recommending a partnership or other entity,
investment plan or arrangement to any taxpayer, then (i) the advice
was written to support the promotion or marketing (by a person other
than Mayer, Brown, Rowe & Maw LLP) of that transaction or matter, and
(ii) such taxpayer should seek advice based on the taxpayers
particular circumstances from an independent tax advisor


This email and any files transmitted with it are intended solely for
the use of the individual or entity to whom they are addressed. If you
have received this email in error please notify the system manager. If
you are not the named addressee you should not disseminate, distribute
or copy this e-mail.

Posted by lance_ryley (lance_ryley@…>)

Michel,
this is why the new standard for DC wiring is Red for positive and
yellow for negative - to keep the old black negative from being
confused with AC hot.

Lance

— In freedomyachts2003@yahoogroups.com, “Michel Capel”
<mike_c_f35ck@y…> wrote:

I just read that in a 110 v system, green is ground or earth,
black
ia positive or hot and white is neutral. Am I mixed up?

— In freedomyachts2003@yahoogroups.com, “Dave_Benjamin”
<dave_benjamin@y…> wrote:

That is exactly what I was referring to. The isolator is
connected
only to the shorepower neutral (green wire typically) right
where
it
enters the boat. The galvanic isolator is a low cost method of
preventing stray current induced corrosion. It also provides
some
safety for a diver or swimmer in the water.

— In freedomyachts2003@yahoogroups.com, “macks011”
<macks04@o…>
wrote:

You may have a different style of galvanic isolator, but mine
is
connected to the shore power ground only, immediately after
the
shorepower socket.
http://www.yandina.com/acrobats/GalvOwnManual.pdf

. — In freedomyachts2003@yahoogroups.com, “Dave_Benjamin”
<dave_benjamin@y…> wrote:

One inexpensive form of protection is a galvanic isolator
that
will
disconnect the AC neutral if it starts carrying current.