Help! Just pulled in to Booth Bay Maine with complete DC electrical failure! My problem started off shore when I turned on the head discharge pump. All DC powered equipment immediatley shut down. No reset helm breakers were out, I turned the head discharge pump rocker switch off right away. I checked the aft port bilge where the discharge pump is located. A little amount of sea water was in bilge that had been slashing around in heavy seas getting the pump and lead wires wet. I checked main DC breaker in the starboard aft battery compartment and it had been tripped. I did a reset, however the all the DC equipment that is specifically turned on at the helm panel do not work. Interestingly, the reset breaker for the discharge pump did not trip open. Any ideas ? Thanks in advance.
DC electrical problem
- Thread starter triton1
- Start date
Wandering Sagebrush
Free Range Human
You have an open between your helm panel and batteries. I suspect the main breaker/fuse, but it could be a loose wire/connection or badly corroded connection.
The main DC breaker opened when the discharge pump was turned on . I reset it and still nothing powered up controlled at the helm switch panel. A year ago I had a faulty main DC breaker and it was replaced! I just checked the three fires at the GUEST Bat. Switch they are all good.
Bob, that is what you get for going "North" for the summers! The electricity is all out of equilibrium up there, in a Southern Boat! :lol:
The head motors use a lot of power, especially if they go to locked rotor. I believe that you have a 40 amp main breaker, and it may even be 60. So we know that something caused that main breaker to blow. There may have been other issues--and I would build on what Steve said. There may have been a lot of resistance, and there may be some other issue--such as a connection which arced, and now there is poor enough conduction, that it will not register voltage, or even a wire burned. (I have seen that happen with a heavy surge load in 12 volts--and it only takes a few milliseconds).
Get out the digital volt meter, and start tracing actual voltage, and if there is absolutely zero voltage, then go to continuity testing. I would also look very closely at the ground circuit (which is not protected by a breaker).
Start at the batteries. Check the voltage, then to the battery switch, each of the terminals of the breaker, then on up the line. It is going to be one of the main wires. (Which may have been undersized to begin with.)
I don't remember the exact layout in your boat, but I think that the holding tank is aft, and you have a macerator pump for overboard discharge.
Let us know what you find. I suspect that it will be fairly obvious when you find it.
Take care
Bob Austin
The head motors use a lot of power, especially if they go to locked rotor. I believe that you have a 40 amp main breaker, and it may even be 60. So we know that something caused that main breaker to blow. There may have been other issues--and I would build on what Steve said. There may have been a lot of resistance, and there may be some other issue--such as a connection which arced, and now there is poor enough conduction, that it will not register voltage, or even a wire burned. (I have seen that happen with a heavy surge load in 12 volts--and it only takes a few milliseconds).
Get out the digital volt meter, and start tracing actual voltage, and if there is absolutely zero voltage, then go to continuity testing. I would also look very closely at the ground circuit (which is not protected by a breaker).
Start at the batteries. Check the voltage, then to the battery switch, each of the terminals of the breaker, then on up the line. It is going to be one of the main wires. (Which may have been undersized to begin with.)
I don't remember the exact layout in your boat, but I think that the holding tank is aft, and you have a macerator pump for overboard discharge.
Let us know what you find. I suspect that it will be fairly obvious when you find it.
Take care
Bob Austin
Hi Dr. Bob,
Well the electrical world maybe different here in Maine, but the cruising is absolutely magical!
We have a 50amp main breaker that has failed open. I confirmed the problem with a test light. I suspect the discharge pump rotor did lock up and created the surge that tripped the main breaker. We ordered an overnight delivery of a Blue Sea 50amp breaker and I will install it early this afternoon, hopefully we will be on our way. BTW how do we handle the discharge pump situation?
Bob, I am so grateful this did not occur while we were operating many hours in pea soup fog. I dead reckoned in to booth Bay under visual conditions. I think I will replace that new breaker with a hydraulic type when I get back to home port. This is the second failed 50amp breaker with in one year!
All the best,
Robert
Well the electrical world maybe different here in Maine, but the cruising is absolutely magical!
We have a 50amp main breaker that has failed open. I confirmed the problem with a test light. I suspect the discharge pump rotor did lock up and created the surge that tripped the main breaker. We ordered an overnight delivery of a Blue Sea 50amp breaker and I will install it early this afternoon, hopefully we will be on our way. BTW how do we handle the discharge pump situation?
Bob, I am so grateful this did not occur while we were operating many hours in pea soup fog. I dead reckoned in to booth Bay under visual conditions. I think I will replace that new breaker with a hydraulic type when I get back to home port. This is the second failed 50amp breaker with in one year!
All the best,
Robert
Second failed breaker, then I would be looking carefully at the entire system. I have always upgraded the wiring in the C Dorys. I have to assume that with the electrical loads you have, that it has already been done. What size wiring from the main battery switch to the console? (same for ground?).
I would be looking at going to a 60 am breaker, in the future, but only after assessing the entire system for occult corrosion, and adequate wire size.
Is the failed motor the macerator on the discharge tank, or a motor on the head bottom unit? As I recollect the motors are similar, but the configuration of the pumps are slightly different.
I have switched over to the diaphragm type of pump for discharge from a holding tank, whenever possible.
The environment that the macerator "lives in" is very hostile. Bilge water, and high humidity, as well as occasional heavy loads, corrosion of pump shaft, and connections subject to corrosion.
Holding tank empty--only pump outs until it is" fixed". (We had the same problem on our 25 in Alaska---fortunately near a city where we could have parts sent in.) Of course there are the "old fashioned ways".
Fog in Maine. We spent a summer there when cruising in our large sailboat. We only had two days of what I would call "pea soup". We had several where it was really wet and cold. The rest of the time, it was great but cool weather.
I'll bet you love that radar!
I would be looking at going to a 60 am breaker, in the future, but only after assessing the entire system for occult corrosion, and adequate wire size.
Is the failed motor the macerator on the discharge tank, or a motor on the head bottom unit? As I recollect the motors are similar, but the configuration of the pumps are slightly different.
I have switched over to the diaphragm type of pump for discharge from a holding tank, whenever possible.
The environment that the macerator "lives in" is very hostile. Bilge water, and high humidity, as well as occasional heavy loads, corrosion of pump shaft, and connections subject to corrosion.
Holding tank empty--only pump outs until it is" fixed". (We had the same problem on our 25 in Alaska---fortunately near a city where we could have parts sent in.) Of course there are the "old fashioned ways".
Fog in Maine. We spent a summer there when cruising in our large sailboat. We only had two days of what I would call "pea soup". We had several where it was really wet and cold. The rest of the time, it was great but cool weather.
I'll bet you love that radar!
If it has been proven that the pump did, in fact, cause the main breaker to trip, I would be concerned that the breaker on that pump did not trip first. Either the pump breaker is a higher rating than the main breaker, or is defective. In other words, the bad pump should have tripped it's dedicated breaker, protecting the main breaker.
Thanks to all for your comments on my DC electric problem. Dr. Bob to your concern, it was the macerator pump, which by the way, I change out last season. In regards to the size wire leading from the bat. Switch to the helm, I do not have a clue! I can't tell a 6 wire from a 8 wire size. I am sure the yard mechanic will be able to tell me. I personally did not upgrade the wiring, perhaps the other two owners may have done so? Yes, I am concerned that the macerator pump breaker did not open with the current surge, perhaps caused by a locked rotor? There should be a split DC bus system in boats, I am told my set up with one main breaker controlling the entire helm activated systems is typical industry design! Thanks again.
anchorout":2cnklu3q said:
Hello Bob,
Anchorout has a great point...WHERE and WHAT is the overcurrent protection for the pump that blew your main breaker? Is it a fuse or breaker? Whatever it is, you need to investigate WHY it didn't do it's job and "open"...instead the "backup" overcurrent protection (the main breaker) opened to save you and your boat from badness (this is how the majority of boat fires occur..."electrical" in origin).
Are your fire extinguishers in good shape?
The wire gauge is printed on the side of the cable. You will need a good light and maybe reading glasses. It should say "6 AWG" or something like that. If it's #6 wire, you could safely use an 80A breaker. If #8, 60A. This is assuming single wire conductor...not bundled into a huge sheath where heat dissipation is more difficult.
Enjoy Maine!
dave
triton1":1gp3ibs0 said:
There are multiple ways to set up a system, but I don't think your way is necessarily a bad thing. You have the fuses or breakers there to protect the wire. Whenever the wire drops down in size, you have to provide protection that is right for that size.
So, you would have a fuse just past the battery (likely a big rating fuse on large wire), then you may step down in size again at a distribution point (such as the main feed line up to the helm area) (in which case a smaller fuse/breaker is at the transition point). Then, you have, say, a fuse block up at the helm (which is sort of a distributed system),. Otherwise you'd have a ton of small wires all going up and back. So then that #6 (or whatever) feed wire goes to the fuse block or maybe fused switches behind the helm, and at that point each wire (which is smaller than the #6) gets a new fuse or breaker.
Essentially you have a tree and at any point where smaller branches occur, you have new/smaller fuses to protect the smaller "branches." It's one of those "branch" fuse/breaker that seems as though should have tripped (presuming the pump is on a wire feed smaller than the main line).
(There might also be some smaller or inline fuses protecting instruments, but the basic setup is for protecting the wires; hence sized according to the ampacity of the wire.)
Of course we don't know exactly what you do have, and just about any production boat electrical system could likely stand some improvement; but the general idea of the C-Dory systems I have seen is not bad.