Reply
 
Thread Tools Search this Thread Display Modes
 
Old 04-30-2021, 01:28 PM   #1
Senior Member
 
City: St. Petersburg
Join Date: Oct 2007
Posts: 266
Unhappy 1979 42' Grand Banks Electrical System

I have started working on subject boat to clear a serious ground fault. I have not been able to locate the neutral bus for either shore power service or the safety ground bus.

It is unhelpful that the boatbuilder used black wire for everything.

I have a lot of experience on older boats but this one has me scratching my head.
__________________
Advertisement

__________________
Charlie Johnson
ABYC Master Technician
CharlieJ is offline   Reply With Quote
Old 04-30-2021, 01:58 PM   #2
Guru
 
City: Clearwater, Florida USA
Vessel Name: Seas the Bay
Vessel Model: 1981 42' Hardin Europa
Join Date: Aug 2016
Posts: 1,482
My memory is that those busses are usually either in the lower helm behind the panel or, in that boat and vintage, more often in the engine room, on the forward bulkhead on the starboard side, beneath the lower helm.

...but each boat is different, as they say!

If all else fails, maybe try disconnecting from shore power, and and any gensets or inverters or other AC power sources, opening the double pole main breakers, e.g. genset and shore, and ringing it from the neutral leg of a double pole breaker back.
__________________

gkesden is online now   Reply With Quote
Old 04-30-2021, 05:12 PM   #3
Senior Member
 
City: Poulsbo, WA
Vessel Name: Archimedes
Vessel Model: Grand Banks 42
Join Date: Jan 2011
Posts: 264
In our boat, which is one year older than yours, the neutral bus is more of a bundle. For us, the AC wiring is all on the starboard bulkhead ahead of the engine. If you follow the wires up toward the ceiling, you will likely find that the wires ago up in a bundle and end with them all connected together in a big crimp at the top. At least that is the way ours was before it was re-wired.
__________________
-- Rusty
Rusty is offline   Reply With Quote
Old 05-01-2021, 02:11 PM   #4
Senior Member
 
Xlantic's Avatar
 
City: Mahón, Menorca
Vessel Name: Halcyon
Vessel Model: 1973 Grand Banks 50
Join Date: Mar 2015
Posts: 283
My previous boat was a 1979 GB42 as well.

Below is photograph of the forward engine-room bulkhead. Lots of wiring but not sure it is the AC circuits.
Attached Thumbnails
P15.jpg  
__________________
Gilberto
Xlantic is offline   Reply With Quote
Old 05-02-2021, 01:50 PM   #5
Guru
 
wkearney99's Avatar
 
City: Bethesda, MD
Vessel Name: Solstice
Vessel Model: Grand Banks 47 Eastbay FB
Join Date: Feb 2018
Posts: 1,595
Quote:
Originally Posted by gkesden View Post
If all else fails, maybe try disconnecting from shore power, and and any gensets or inverters or other AC power sources, opening the double pole main breakers, e.g. genset and shore, and ringing it from the neutral leg of a double pole breaker back.
heh, time to get out the test probe.

It took 8 hours to find the windlass fuse on our EB47. Tracked the wires all over the boat. It was finally only by accident of my fidgeting tapping the probe speaker buttons and leaning a sweaty hand against a panel that I finally heard where the last point of circuit was located. BEHIND a screwed-in faceplate.

sure hope the owner is prepared for the hours you'll have to bill to track it all down...
Attached Images
 
__________________
-- Bill Kearney
2005 Eastbay 47 FB - Solstice
wkearney99 is offline   Reply With Quote
Old 05-02-2021, 02:35 PM   #6
Senior Member
 
City: St. Petersburg
Join Date: Oct 2007
Posts: 266
After wandering around the panelboard and what is laughingly the "busses" in the E/R, I left screaming off the boat and ran down the dock, the Owner tackled me and said "What is wrong?" I said if you are going to keep this boat, the panelboard should be replaced, two proper neutral busses and a safety ground bus established. Ballpark is $10k.

Barring that, I am going to use all the tricks of the trade to find out where the boatbuilder hid the neutral and safety ground "busses". As Rusty pointed out upthread, on his GB the "bus" was actually a "bundle".

The photo shows the problem that I am trying to correct. This is serious, very, very serious.
Attached Thumbnails
First Light - 1.jpg  
__________________
Charlie Johnson
ABYC Master Technician
CharlieJ is offline   Reply With Quote
Old 05-02-2021, 02:39 PM   #7
Guru
 
wkearney99's Avatar
 
City: Bethesda, MD
Vessel Name: Solstice
Vessel Model: Grand Banks 47 Eastbay FB
Join Date: Feb 2018
Posts: 1,595
Quote:
Originally Posted by CharlieJ View Post
The photo shows the problem that I am trying to correct. This is serious, very, very serious.
Yikes!

I've learned over the years with electrical that unless you find it in first day's worth of qualified troubleshooting that it's probably going to be cheaper in long run to rip-and-replace. Otherwise you end up burning through a ton of billable hours to figure out almost everything involved is screwed and needs replacing anyway.
__________________
-- Bill Kearney
2005 Eastbay 47 FB - Solstice
wkearney99 is offline   Reply With Quote
Old 05-02-2021, 02:59 PM   #8
Senior Member
 
City: St. Petersburg
Join Date: Oct 2007
Posts: 266
@wkearney99
Agree 100%. With some new found info and a very motivated Owner doing some extensive hand over hand work, if we haven't sorted in one more day it replacement will be the least expensive and most sure way of correcting this.
__________________
Charlie Johnson
ABYC Master Technician
CharlieJ is offline   Reply With Quote
Old 05-09-2021, 10:17 AM   #9
Guru
 
diver dave's Avatar
 
City: Palm Coast, FL
Join Date: Jan 2017
Posts: 2,012
Quote:
Originally Posted by CharlieJ View Post
After wandering around the panelboard and what is laughingly the "busses" in the E/R, I left screaming off the boat and ran down the dock, the Owner tackled me and said "What is wrong?" I said if you are going to keep this boat, the panelboard should be replaced, two proper neutral busses and a safety ground bus established. Ballpark is $10k.



Barring that, I am going to use all the tricks of the trade to find out where the boatbuilder hid the neutral and safety ground "busses". As Rusty pointed out upthread, on his GB the "bus" was actually a "bundle".



The photo shows the problem that I am trying to correct. This is serious, very, very serious.


Looks like there are two shore cables in that pix? If so, they will likely be sharing the neutral current. Also, both would show the 11Amp unbalance.
diver dave is offline   Reply With Quote
Old 05-09-2021, 11:02 AM   #10
TF Site Team
 
Comodave's Avatar
 
City: Au Gres, MI
Vessel Name: Never Say Never
Vessel Model: President 41 DC
Join Date: Jul 2015
Posts: 11,852
Quote:
Originally Posted by diver dave View Post
Looks like there are two shore cables in that pix? If so, they will likely be sharing the neutral current. Also, both would show the 11Amp unbalance.
They probably are but they should not be sharing the neutral. A lot of older boats are this way.
__________________
Boat Nut:
If you are one there is no explanation necessary.
If you aren’t one, there is no explanation possible.
Comodave is online now   Reply With Quote
Old 05-09-2021, 11:13 AM   #11
Guru
 
diver dave's Avatar
 
City: Palm Coast, FL
Join Date: Jan 2017
Posts: 2,012
Having two isolated neutrals will fix the shore power cables sharing unequally, but make it more complex inside the boat. There is now a L1, L2, N1, N2 to work with.
Maybe better to do the 240/120 50A system with just the one cable. And one neutral.
diver dave is offline   Reply With Quote
Old 05-09-2021, 11:44 AM   #12
Senior Member
 
City: St. Petersburg
Join Date: Oct 2007
Posts: 266
@diver_dave and @Comodave

Correct. I found that SP1 current is coming back on SP1 N as well as SP2 N and vice versa. That is why the hunt for the elusive N busses and the Safety Ground bus is so essential to correcting this extremely dangerous issue.
__________________
Charlie Johnson
ABYC Master Technician
CharlieJ is offline   Reply With Quote
Old 05-09-2021, 04:20 PM   #13
Guru
 
Soo-Valley's Avatar
 
City: Gulf Islands, BC Canada
Vessel Name: Soo Valley
Vessel Model: Grand Banks 36
Join Date: Jul 2019
Posts: 2,549
You are clamping a shore cable and get 11A.
Are you getting 0 if both are clamped together?
__________________
SteveK AKA Soo Valley
You only need one working engine. That is why I have two.
Soo-Valley is online now   Reply With Quote
Old 05-09-2021, 06:08 PM   #14
Senior Member
 
City: St. Petersburg
Join Date: Oct 2007
Posts: 266
@Soo-Valley
Short answer is no. This was the first of several diagnostic tests performed. I installed to break out adapters between the pedestal outlets and the shore cords so that I could clamp individual conductors or any combination thereof. There is truly 11 to 15AAC leaking into the water column.
__________________
Charlie Johnson
ABYC Master Technician
CharlieJ is offline   Reply With Quote
Old 05-09-2021, 06:12 PM   #15
Guru
 
Soo-Valley's Avatar
 
City: Gulf Islands, BC Canada
Vessel Name: Soo Valley
Vessel Model: Grand Banks 36
Join Date: Jul 2019
Posts: 2,549
wow! look forward to what you find
__________________
SteveK AKA Soo Valley
You only need one working engine. That is why I have two.
Soo-Valley is online now   Reply With Quote
Old 05-09-2021, 06:15 PM   #16
Guru
 
diver dave's Avatar
 
City: Palm Coast, FL
Join Date: Jan 2017
Posts: 2,012
No diving around that boat
diver dave is offline   Reply With Quote
Old 05-09-2021, 06:18 PM   #17
TF Site Team
 
Comodave's Avatar
 
City: Au Gres, MI
Vessel Name: Never Say Never
Vessel Model: President 41 DC
Join Date: Jul 2015
Posts: 11,852
That is really bad. Wonder if it is just from commingled neutrals or is something else going on.
__________________
Boat Nut:
If you are one there is no explanation necessary.
If you aren’t one, there is no explanation possible.
Comodave is online now   Reply With Quote
Old 05-09-2021, 06:19 PM   #18
Senior Member
 
City: St. Petersburg
Join Date: Oct 2007
Posts: 266
@diver_dave: ABSOLUTELY! The Owner is extremely conscientious, and I have thoroughly briefed him. The electrical field that is being developed could, emphasize the word could, be deadly even in the salt water that the boat is in.
__________________
Charlie Johnson
ABYC Master Technician
CharlieJ is offline   Reply With Quote
Old 05-09-2021, 06:21 PM   #19
Senior Member
 
City: St. Petersburg
Join Date: Oct 2007
Posts: 266
@Comodave: The wiring on this boat defines the phrase FUBAR. I have already found and eliminated one N > G connection. Didn't change a thing at the pedestal!!

I will post my findings here so all can, hopefully, learn a bit.
__________________
Charlie Johnson
ABYC Master Technician
CharlieJ is offline   Reply With Quote
Old 05-09-2021, 06:27 PM   #20
TF Site Team
 
Comodave's Avatar
 
City: Au Gres, MI
Vessel Name: Never Say Never
Vessel Model: President 41 DC
Join Date: Jul 2015
Posts: 11,852
I worked on a friend’s boat since it would trip the dock breaker on the newly wired docks. Found 4 problems, all neutrals on 1 bus, both volt meters wired to 1 neutral, neutral to ground short inside water heater and one outlet with the neutral and ground wires reversed. He said that standing in the water by the boat he felt a tingling but thought it was just cold water effect. Fortunately he was standing and not swimming.
__________________

__________________
Boat Nut:
If you are one there is no explanation necessary.
If you aren’t one, there is no explanation possible.
Comodave is online now   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



» Trawler Port Captains
Port Captains are TF volunteers who can serve as local guides or assist with local arrangements and information. Search below to locate Port Captains near your destination. To learn more about this program read here: TF Port Captain Program





All times are GMT -5. The time now is 12:51 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012
×