Shore Power Issues

T

tsolms

.
Oct 30, 2019
5
I was aboard my boat last Sunday to find that I wasn't getting any shore power aboard. I checked all of the circuit breakers on the dock and on the boat without finding issues. I finally found that the cable was fried where it mates with the power fitting on the port cockpit. The specific location of the meltdown is where the angled male prong enters the shore power cable.

Needless to say, I disconnected everything and immediately replaced the cable. Problem is that the new cable fried in the exact same manner within about an hour.

I'm now planning on replacing the three AC outlets with new GFI outlets and to replace the shore power fitting on the boat.

Any other ideas?

Info - I have a few things plugged in below but they've been plugged in regularly with no issues.

Thanks,

Tim Solms
Kerstin
Alexandria, VA
 
T

tom_rutter

.
Aug 3, 2005
66
Hello,

Does it still fry when the power is switched off inside the boat? I guess
you need to find whether the short is outside your main power switch. If so,
that's probably the bit you need to concentrate on replacing. Perhaps your
socket is broken?

Tom
 
T

tsolms

.
Oct 30, 2019
5
Tom,

Appreciate the reply & Advice. When I connect shore power, the three AC outlets below are hot. I do not have an On/Off capability for those other than the circuit breakers. So, I can't really answer your first question.

I picked up a new power outlet for the hull and am getting the new outlets tomorrow and will see if there is any improvement.

Tim
 
P

pelagicasd

.
Jan 28, 2001
694
Tim, Check your voltage. We had 20 amp service on our dock. Some folks were changing to 30 amp breakers. The problem with that was the further out on the dock you got the less voltager was available. As voltage drops resistence increases. As the resistance increases heat goes up. One boat burned to the waterline and when a friend measured voltage at the dock box he found 80 volts. Walt
To: AlbinVega@yahoogroups.com
From: timsolms@...
Date: Tue, 19 Jan 2010 22:31:17 +0000
Subject: [AlbinVega] Re: Shore Power Issues


Tom,

Appreciate the reply & Advice. When I connect shore power, the three AC outlets below are hot. I do not have an On/Off capability for those other than the circuit breakers. So, I can't really answer your first question.

I picked up a new power outlet for the hull and am getting the new outlets tomorrow and will see if there is any improvement.

Tim
 
E

edbawden

.
Jun 7, 2009
18
Hi Tim

Too many years ago to mention I qualified as an electrician, but without seeing your set-up advice can only be general.
Problem ? cable was fried. This can only happen because too much current passed through the cable. The point of failure is the point of greatest resistance. Having the same fault with a new cable proves only that the original cable was previously in good order and so not the cause.
Possible cause: 1. You simply have too much load. Check all the devices you have connected. They should state the current in Amps. Total all these up and compare against the rated current for the cable you are using. There are charts available for AWG and mm2 size cables on the net. Be cautious of trying to fix the problem by increasing the cable size. You could just be pushing the problem to a failure elsewhere in the circuit and many fires are started by electrical faults.
Possible cause: 2. You have a fault on the circuit or one of the devices connected. The fault could be with the device or the cable going to it. I see you are replacing the sockets so that will eliminate any problem with your old ones. When you power up do it in sequence and initially with all devices unplugged, then with each device plugged in alone. You should allow time for any fault to be evident at each stage. If you can get the use of a clip-on ammeter, check the current of each outlet and compare against the data plate for the device connected.

I response to some of the other advice I read. A low supply voltage at the Doc box is because of voltage drop across the supply cable. As users find more items they wish to power the increased load (current) causes a larger volt drop across the supply cable. Note the cable may be correctly sized for the current, but the longer the cable the greater its resistance. Increasing the size of the supply cable by the marina will rectify this.

Resistance of the device is fixed. Resistance of the cable is fixed and is proportional to the length of the cable. A reduction in the supply voltage will not change the resistance. Reduced voltage at the Doc box is not unsafe, but some things will not work and others will work slower. Reduced voltage will not cause over heating.

Sorry for being so long winded but it is important to find the cause of the fault. Boats left unattended with a potential electrical fault can be destroyed by fire.

Ed
Dizzy Daisy
 
S

SVFlyAway

.
Oct 31, 2019
303
Ed,

Excellent explanation. I would like to add/ask one thing.

It seems to me that some circuit breaker should have tripped before the
cable melted. It takes a lot of power to melt a shore power cable. So, if
the problem is on your boat (after your circuit breaker panel) isn't there
is a problem with the boats circuit breakers?

But the bigger question I have is why the "dock box" circuit breaker didn't
break. Ed, if there was enough current to melt the cable, shouldn't have the
circuit breaker on the dock tripped? A cable should never be smaller than
the load allowed by the circuit breakers. That raises another question to
Tim, are you using an adapter to fit a smaller cable into a bigger dock
plug, with a higher capacity circuit breaker? Tthis could override the
circuit breaker. This is commonly done, I carry all kinds of adapter on my
boat since marinas aren't standardized -- but my power consumption is
small, even with the little heater I have onboard in the winter. I was
trained as an ABYC electrician (but never bothered to take the test, so as
with Ed, I am very aware of electrical loads and carry meters to check these
-- as well as the proper grounding of the marina circuits!!!!).

Chris

On Thu, Jan 21, 2010 at 10:39 AM, walt/judy brown/allore
bestvega@... wrote:
 
E

edbawden

.
Jun 7, 2009
18
Chris
You are right. All protection devices (including the "doc box" circuit breaker) should be sized to protect the down stream cable. However the marina would have designed the system for the max load they expect at each doc box. They are not in control of what cable is attached downstream. That is why I advised Tim to check the cable size and his total load. The connector has a max design load (in UK this is 15A). The cable should be sized for this.I discounted the possibility of poor (corroded) connections. because the same fault occurred when the cable was replaced.
There are many designs of protection devices - fuse, circuit breaker etc. It is possible to pass more than 15A through a 15A fuse or circuit breaker without it blowing and disconnecting the power. If you have a short the current will rise rapidly and the protection device will operate and protect the cable. But if the load is increased slowly the protection devices will take time to heat up and react. Before they react the weakest point in the circuit (the point of greatest resistance i.e. a cable connector) could over-heat and fail. This is why it is important to check your total load.
Tim, please let us all know how you progress.
EdDizzy Daisy
 
S

SVFlyAway

.
Oct 31, 2019
303
Ed,

I agree. I was assuming (a stupid thing to do I guess) that the shore power
cable was one of those big yellow, about the size of a garden hose, that run
12 gauge wires (used for 120 volts, I envy you Europeans running 220 being
able to use the smaller cable. A 12 gauge wire 50 feet long should be able
to handle enough power not to melt before the breaker trips. I agree, not
knowing exactly what the cable is and the power load does leave
troubleshooting kind of in the dark (literally if the power cable fails!).

Of course the first thing I'd do, and I assume you too (based on your
experience), is to meter the voltage at the dock box and also at the cable
end. Then do the inside of the boat. I would also ohm out all the connectors
and plugs. One other thing I'd do is to have the marina have their
electrician check the dock box out.

I agree about circuit breakers, they do get old and sometimes won't trip
with a slow build up. I often run 25 amps on a 20 amp circuit in my shop,
but I build it up slowly -- and the wiring is 12 gauge, not 14 that is
allowed by code. Actually a 20 amp breaker will allow more current than the
rated 20 amps for a short period -- to allow a motor to spin up (my 15 amp
saw motor draws 25 amps at start, then drops close to 15 amps). The NEC
rules allow for this as I recall.

Chris
 
G

groundhogyh

.
May 30, 2006
1,075
Hi,I was out last week and just read these posts. One thing that may be added to the discussion (may have already been said and I missed it.), is that the resistance of the plugs can increase, i believe, with use. The metal to metal connection of the plugs deteriorates with use, especially with higher amperage. These points can get hot because of the increasing resistance at this point.Also, did the system originally work for a long time?
If so, the likelyhood of success by replacing the old connectors/breakers/cabling is higher. Roy
 
T

trevy_kins

.
Oct 31, 2019
230
Hi gang, am thinking of replacing my cylindrical boom with one of a
rectangular box-shaped profile for added rigidity. Can anyone please
tell me the length of the Vega boom? Thanks, Trevor (V2915)
 
J

j.hunter9999

.
Oct 30, 2019
574
Trevor,
If there are no replies by Saturday, I'll be at the boat on Sunday and will take a measurement.

Jack,
Bella - V2620
 
B

bobnlesafloat

.
Oct 31, 2019
163
Just been up on Deck and measured Spring Fever's which I believe is the original/standard boom (Procters, Circular, Gold Anodised) for a Mark 2 Vega and length is 11' 2"/3.405m. That's the boom only it includes the end-caps, but excludes the gooseneck and mainsheet fittings.

BobnLesley
Spring Fever 1776.
 
T

trevy_kins

.
Oct 31, 2019
230
Thanks BobnLesley, I wonder if my newer series non-anodized one is the
same? Any ideas out there? Thanks, Trevor (V2915)



________________________________

From: AlbinVega@yahoogroups.com [mailto:AlbinVega@yahoogroups.com] On
Behalf Of Bob Carlisle
Sent: January 26, 2010 3:36 AM
To: AlbinVega@yahoogroups.com
Subject: RE: [AlbinVega] Boom Measurement - Mark 2 here





Just been up on Deck and measured Spring Fever's which I believe is the
original/standard boom (Procters, Circular, Gold Anodised) for a Mark 2
Vega and length is 11' 2"/3.405m. That's the boom only it includes the
end-caps, but excludes the gooseneck and mainsheet fittings.

BobnLesley
Spring Fever 1776.
 
J

j.hunter9999

.
Oct 30, 2019
574
Yep. Do you need that one, or the one Bob gave you? I'll watch and if I don't see anything posted, I'll measure and post it on Sunday.
 
J

j.hunter9999

.
Oct 30, 2019
574
Trev,

I took the measurement off my boom. It is the original aluminum Proctor Spar. I wasn't sure exactly which measurement you needed. So, the boom measures 133.5 inches from the forward part of the gooseneck to the aft end of the end cap (not including the point at which the topping lift attaches.

It is 134.75 inches including the piece where the topping lift attaches. Just the aluminum boom is 130.5 inches (not including the gooseneck or topping lift attach point).

If any of that is confusing (because its confusing the heck out of me, and I was the one that measured it), let me know and I'll try to clarify. I might also be able to shoot a picture of a spar (not mine) and mark the reference points.

Jack,
Bella - V2620
 
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