Shore Tie Panel

[cscam56]

I am a new member of the forum and own a 79 DCMY43. I just got finished reading some older posts about Barry Barbour's fire which started at the shore tie panel. I have a similar experience to share and am most interested in how others have replaced the inlet panel.

I live on my boat during the week to avoid commuting 150 miles daily to DC. I returned on Sunday, as usual, and smelled that sweet yucky fragrance of burned electrics. I went below to discover that except for the AC circuit, which I have running some small space heaters, the boat was electrically dead.

I discovered that the port short-tie panel and the fuse holders were melted! Fortunately, the shore-tie cables were spared and I was able to shift them to the starboard panel. I'm convinced that the load on the panel was too great due to the space heaters. I am stunned that the fuses appear not to have worked properly (all four fuses were replaced a couple of months ago) and allowed the whole assembly to melt. I feel very lucky the damage was limited to the panel and the immediate interior wiring.

Here's my question - What's the best way to fix or replace the panel so that it doesn't do that again, and should the starboard panel receive the same fix?

Collin
cscam56
HIGHLANDER
Ft. Washington, MD

 

[garyd]

I removed that panel and fuses and have never had a problem.

Most small to medium size boats do not have that inlet panel as you called it.

I believe there is some "rule" that the length of wire from the electrical inlet to the fuse should only be X feet. I believe x = 15 but that is from memory. Your run may be longer than that but would you rather break a abritrary rule or burn down your vessel.

garyd

 

[eze2bme]

I am curious. I too have a 1979 43DC ... but my boat has only one shore inlet panel located on the starboard wing wall of the aft deck where the shore cords attach. Were your dual inlet panels OEM or added? I've never seen another 43DC of our vintage with two inlet panels. Thanks.

 

[REBrueckner]

I am not familair with the specific panel you refer to but I CAN explain the problem mechanism. Corrosion specks create a poor contact....a normal current load must now flow thru tiny pinpoints of corrosion contact and they get hot enough to cause fire!!!...this typically happens at male to female plug inserts and between fuses and their holders...rotate fuses in place once or twice annually to scape off surface corrosion...spray with an electrical moisture dispersant...These pinpoints of corrosion can also cause fuses to blow (melt) from heat even when currents are normal and modest. Another precaution is to disassemble your shore power cord and tighten the cable to plug fastening screws....most loosen over time.

 

[Trojan]

My 73 43DCFB has a dock side panel on the starboard side with a water connection. On the port side I have 3 power connections and no panel. I have no fuses in line from ether side to the main rotor switch to the main power panel.
I have said this in the past and I will say it again. YOU MUST check these connections a minimum of every 6 month or more. This is a major cause of boat fires. Any corrosion build up on the connections in this string will cause unwanted arcing in the connection and sure to cause a meltdown without blowing a fuse. This is a high amp draw area and it must be KEPT CLEAN and TIGHT. It would be a good idea to make sure that nothing burnable is in the close proximity of these wire connections. Consider yourself lucky Collin. The fuses are there to protect the power cord and the chain to the shore connectors. Excessive current did note do this. Dirty or loose connections did. I to was aware of this potential and made sure there was nothing around mine. I check monthly, but I awoke one morning and smelled that same stench. The wires on the port side were complety burnt off the backside of the shore power connector and hanging in the air. The back side of the plug was complety destroyed. Count your blessings that is all the damage that occurred and just replace it all and check it from now on. The fuses on a lot of the boats were removed due to nuisance blowing of the fuses.

BILL

 

[TedZ]

Small space heaters? How small? They are on when you are gone? These are built-ins or Wal-Mart variety? Most of those heater are 1500 watts. Two or more is a lot for continuous use.

Anti-ox on the plugs works wonders to keep resistance low.

Ted

 

[sgharford]

Trojan (Bill) - did you remove (bypass) the fuses on starboard shore side connection? I have had allot of nuisance trips with air conditioner 30 Amp supply side on my 43DC and was thinking of taking starboard panel apart and maybe replacing 30 amp cartridge fuses with circuit breakers. However, with circuit protection already built in at main panel – did seem rather redundant. The fuse holders and prongs are clean for what it’s worth.

 

[REBrueckner]

When I first posted I did not take proper note of the fact you had replaced fuses recently. Often just yanking them in and out scrapes the holders clean...but if you did not rotate fuses in holders it could easily have been a corrosion contact problem as I posted above.

If you had two 1500 watt electric heaters on high they would draw about 25 amps total at 120 volts when both are heating...what size were the fuses? a 30 amp circuit should handle that load...but if a water heater, for example, kicks on and off, that would likely overload a 30 amp circuit.

On board fuses have nothing to do up the shoreside power coming into the boat...they protect only on board appliances and wiring, that is, anything on the boat/load side not the supply/shore side of the fuses...

 

[stormchaser]

I too had a problem with the fuses getting so hot that they melted/burt the holders. The PO had the wrong fuses in there! So, make sure they are the right ones for your boat. was lucky, no damage to the panel other than needing to replace the fuse holders.

I wonder how hard it would be to replace the fuse holders with a circuit breaker? With the Bussman style fuses...you can't really SEE whether the fuse is good.

 

[Pascal]

how many of us regularly check for heat on our shore power plug when a heavy load is on? takes a few seconds...

i think the max distance between the shore power inlet and the main CB acc. to ABYC is 10'... If you can get access behind the area where the inlets are, or just under it, you could install a main CB there. Just like the old fuses, this will only protect the wiring from the breaker to the main panel... it will not do anything for the inlet. your shore inlet (and cord) is protected by the SB on the dock, not by whatever is downstream.

an alternative woudl be to mount the CB in one of the shore power inlet cover so that's it's accessible yet protected. some buidlers do that to comply with ABYC standards. All builders now use CBs instead of fuse, i dont think there any logical reason to keep using fuses.

http://www.cmsquick.com/prod_23.html

I dont' have fuses on my old 53, apparetnly they were removed in the past but they are not really needed since they were mounted in the ER, under the inlets, and right next to the electrical panel (which on the early 53 is in the port ER).

 

[cscam56]

All,
Thanks very much for your comments. I've been out of town and haven't checked back-in until today.

My boat appears to have two OEM panels, one port, one starboard, that accept two shore-tie cables and a water connection. I know the starboard panel has a cable tv connection as well. I can't recall if the port side has the cable connection too.

One of you mentioned that the PO had the wrong size fuses in the panel and that shook me because I replaced the two 30 amp fuses (4 total on each panel) with the same. Can anyone say whether or not that is the correct size? It seems two 30 amp fuses per shore-tie might be too high.

I do run electrical space heaters. I have 4 different types. Off the AC circuit I run a radiator style/oil filled heater and a IR heat panel. Off the other shore-tie I run a ceramic heater for the aft cabin head and a Vorando that does a good job of moving air throughout the main cabin.

I like the set-up of living on the boat during the week and have been thinking that investing in a diesel heater may be smart in the long-run.

If any of you have replaced these OEM panels, how have you done so?
Appreciate your comments and insight.
Collin

 

[stormchaser]

It it is a 30a connection, 2 30-amp fuses is correct. If it is a 50a, 2 50s would be correct. The key is that they should be Bussman FRN-R series fuses...not the NON series.

 

[cscam56]

Dave,
I had no idea there were differnt types of these fuses. I picked mine up at a hardware store, as the PO said he'd gotten his. I will check. Is there a marking I should check for or just go to a marine store and they'll have the right product?

I recognize that the fuses only protect from the inlet panel to the main CB - and that's fine. I just want to install something that gives me confidence a circuit will pop before damage is done.
Collin

 

[stormchaser]

This is sorta assuming you have the "bullet" style Bussman fuses.

They say either FRN-R or NON right on the label.

 

[Trojan]

The 2 fuses that are in question are current limiters. They are there to protect your shore power cord and the in-line connections. They do not protect the wires from the fuse to the main terminal block. The terminal block uses the breakers in the panel for protection. The current is always higher at the end of a cord because of the resistance. As in the dirty twist-lock on the side of the boat or the dirty fuse holder. That is why the fuses get hot and that is why they burn up. The current is the highest at this point. You take it from there. Take them or leave them.


BILL

 

[stormchaser]

I think you've got it backwards...fuses can only protect FORWARD of their location. They cannot protect back. Basically the protection is AFTER the fuse...so the fuses at our shore inlets do indeed protect the wire between the inlet and the main breaker(s). It's the breaker on the dock or at the pedestal that protects your cord and the pedestal itself.

 

[Trojan]

I think you've got it backwards...fuses can only protect FORWARD of their location. They cannot protect back. Basically the protection is AFTER the fuse...so the fuses at our shore inlets do indeed protect the wire between the inlet and the main breaker(s). It's the breaker on the dock or at the pedestal that protects your cord and the pedestal itself.

Fuses can and are used to protect ether way. The breaker at the shore pedestal won't protect your power cord. If you think it will, Sorry. If the fuses are used to protect the power panel, then just leave them out. The pedestal will do that to. Hell do what ever you want. It's not my boat that going to catch an fire. I'm done.

BILL

 

[stormchaser]

I'll be the first to admit that I could always be wrong. Can you explain how a fuse can offer any protection before it?

Also, I didn't say it would protect the panel...I sai it protects the wire betwen the fuse and the main breaker.

 

[Trojan]

By rights from the pedestal to the main panel all the current load should remain the same. But when the load is running on the high side of the current load. The current can start to change. Any resistance that is in between the two points will make the current rate start to go up at that point. A dirty connection at the twist lock can raise the current beyond the amount the twist lock plug will pass. The resistance rise along with the current will continue to grow. In turn the twin fuses that are within a few inches or so of the twist lock are now beginning to be see the current rise at the fuses. The wire between the two ( should ) will not heat at this point because of its size. The fuses are of the thermal type and start to warm and once they reach there thermal value they open. The plug is saved maybe and no more current flows. The closer the fuses are to the resistance the better they work. If the fuses were mounted far away they would protect almost nothing. This is not a normal use of fuses. A breaker would work, but you would see a lot more nuisance trips. Maybe I'm wrong, do it your way its not my loss. Did you ever have a fuse or breaker blow at the pedestal when the plug there was dirty. Never the plug and wire just fry. The wire size between the pedestal and the boat should be of such size that there could never be a failure because of a fuse or breaker was rated at the correct value.

BILL

 

[TedZ]

Think of the wiring as a system. Forwards or backwards does not help in the analysis and has no meaning.

So you have all connected in a single line a 50 amp breaker then 50 feet of 6 ga. wire to a 30 amp breaker then 30 feet of 10 ga. wire to a 10 amp tubular fuse connected to a 14 ga. wire connected to an amplifier, say a stereo.

If the stereo could draw 100 amps the pedestal breaker/fuse would trip but it can't so the 10 amp fuse blows. If the 14 ga. wire lays on ground on the supply side of the 10 amp fuse, the 30 amp breaker should trip. If the wire feeding the 30 amp goes to ground the 50 amp breaker should trip.

If there is high resistance to ground in any scenerio the breakers don't see more current they see less and might not trip. This is where heat comes in and fires can start. High resistance means toaster!

In EACH situation a GF breaker would likely trip 99.99999% of the time. Very good to use those on boats for every breaker.

This is hypothetical but i hope makes it a little clearer...maybe not!

Ted