Eletrical Overload ... sometimes

BrontideRob

BrontideRob

.
Mar 7, 2012
21
Hunter 460 San Diego
I could use some guidance on what to troubleshoot.

In a nutshell, turning on some circuits with specific characteristics sometimes causes a persistent overload of the DC side of our electrical system.

Here one scenario:
  • Start with all circuits breakers on the DC Panel in the off position.
  • Turn on the main breaker - It lights. All good.
  • Turn on a device that draws power immediately, e.g., the anchor light. - Breaker light comes on. Device comes on. All good.
  • Turn off device in c - All good.
  • Turn on a device that draws a lot of power slowly, e.g., the VHF radio or Entertainment System. Breaker light comes on. Device comes on. All good.
  • Turn on device in c (Instant power user) - Breaker light comes on. Device comes on. All good.
  • Turn off device that draws power slowly (same as e above). - All good.
  • Turn back on device that draws power slowly (same as e above). - Entire panel goes dark. All breaker lights off. All devices off. Not good.
  • Turn all circuit breakers off.
  • Turn on main breaker - Breaker light comes on.
  • Turn on a device that draws power immediately (same a c above) - Entire panel goes dark (including main breaker light) - Not good. (in other words, that which worked before does NOT work now.)
  • Turn off the device you just turned on (the one that draws power immediately, same as c above) - Main breaker light comes back on.
  • Turn on device that draws power slowly (same as e above) - Main Breaker and Device breaker lights start out dim but get normal in a few seconds. Device is on. All appears good.
  • Turn on device that draws power immediately - Device comes on and all appears good.

Thank you for any guidance you can provide.

This may be unrelated, but maybe not. We were recently in the San Blas Islands and VERY near to several lightening strikes. My radar scanner has stopped working also, or I should say that during warm-up, I only receive "Warning: Scanner is not responding" and the warm-up period begins again.
 
A

ALNims

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Jul 31, 2014
208
Hunter 356 Huis Ten Bosch Marina, Sasebo, Japan
Bob,
Does your main breaker trip? What is the DC voltage reading on your panel when all lights go out? What is the condition of your batteries including connections?
 
uncledom

uncledom

.
Jun 11, 2011
1,243
Hunter 41 Lewes
Turn off the battery switches, and or disconnect the battery/ies, open the panel and check every connection. Look for loose wires and discoloration. If it was lightning there could be damage from over voltage. Check all connections all the way back to the battery/ies. That's a good first step.
 
kloudie1

kloudie1

.
Nov 6, 2006
10,213
Hunter 34 Mandeville Louisiana
Sounds like a bad connection either to the panel from the batteries (positive side) to the panel, or from the panel to batteries .. major ground connections, including the battery connections. Check the negative side connections carefully 'cause if ya had a little over-voltage spike from nearby lightning, it would be tyring to get out through the bonding on negative side. sounds like the connection is marginal and when it heats a little from current passing, it opens.
 
BrontideRob

BrontideRob

.
Mar 7, 2012
21
Hunter 460 San Diego
The main breaker does not trip. The light indicating voltage to the breaker goes off, but the breaker itself remains in the on position.
DC Voltage at the panel is 12.9V before flipping the switch that causes the panel to go dark. While dark, the voltage at the main breaker reads 0.160V. It stays at this low voltage (and dark) even after turning the VHF breaker off as described above.
The battery conditions and connections are good. I have two banks of house batteries and get the same results whether I use Bank 1 alone, Bank 2 alone, or Bank 1 & 2 together.
 
BrontideRob

BrontideRob

.
Mar 7, 2012
21
Hunter 460 San Diego
Thank you. Will do.

uncledom said:
Turn off the battery switches, and or disconnect the battery/ies, open the panel and check every connection. Look for loose wires and discoloration. If it was lightning there could be damage from over voltage. Check all connections all the way back to the battery/ies. That's a good first step.
Click to expand
Thank you. Will do.
 
BrontideRob

BrontideRob

.
Mar 7, 2012
21
Hunter 460 San Diego
Thank you. Will do also.

kloudie1 said:
Sounds like a bad connection either to the panel from the batteries (positive side) to the panel, or from the panel to batteries .. major ground connections, including the battery connections. Check the negative side connections carefully 'cause if ya had a little over-voltage spike from nearby lightning, it would be tyring to get out through the bonding on negative side. sounds like the connection is marginal and when it heats a little from current passing, it opens.
Click to expand
Thank you. Will do. Your last two sentences would explain the symptoms I am seeing, especially the persistency of the low voltage after the breakers are reset.
 
L

LloydB

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Jan 15, 2006
927
Macgregor 22 Silverton
ground fault? -disconnect radar circuit. even tho it's not turned on. do you have solar?
 
Maine Sail

Maine Sail

.
Feb 6, 1998
11,759
Canadian Sailcraft 36T Casco Bay, ME
Sounds like a loose connection somewhere. Check all connections, both positive and negative, all the way back to the batteries. Could also be a failing breaker.
 
Bill Roosa

Bill Roosa

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Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
sounds like you need a new main CB. lightning creates large magnetic fields which can induce currents in your wiring (and anything else metal BTW). A large current induced in the CB can cause it to go south if it is a magnetically tripped slow tripping type.
 
Bill Roosa

Bill Roosa

.
Jun 6, 2006
6,990
currently boatless wishing Harrington Harbor North, MD
To test the CB just get a jumper wire and temporarily jumper from one side to the other bypassing the main breaker and see if your symptoms go away.
 
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BrontideRob

BrontideRob

.
Mar 7, 2012
21
Hunter 460 San Diego
Conclusion (Likely): Bill Rossa was right. Main DC Circuit Breaker.

Details: I believe three things contributed to the problem. 1) I went though all wires looking for Ground Faults and DID find a minor one related to corrosion on a courtesy light that we never use. 2) While not 'excessively bad', I did clean up the main connections to the house batteries. After those two corrections, the problem still appeared. 3) I replaced the main circuit breaker for the DC Power Distribution Panel.

While I can't swear the problem won't reappear because it was 'occasional' from the beginning, we have NOT seen the problem since replacing the main breaker. It's be a few weeks now, so I am optimistic that the problem has been addressed. If I later discover that is not the case, I'll be sure to come back here with an update.

THANK YOU ALL FOR YOUR HELP. IT WAS ALL VERY VALUABLE TO ME!
Sincerely,
Rob Benson
s/v R&R Kedger currently in Belize this month. :)
 
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