Another arc at the shore power plug

R

rogerbum

New member
I remember reading Jim's post this summer about having an arcing even at his shore power connection and how he replaced his Marinco plug with a Smart Plug. At the time, I thought, I should probably do the same prior to the arc. But then I looked at the price and thought hey, I got 7-ish years out that connector on my old boat and the current boat is newer, it can wait. Well.....

I went out to the boat yesterday to do some other wiring work and discovered there was no power on the boat. The plug was lit up so I knew I had power to the boat but it wasn't making it to the panel (which had a reverse polarity indicator lit). So I disconnected the breakers and took the shore power cord out the connector at the boat. It was tough to remove and lo and behold, I see this.
BurntPlug.jpg

There was a corresponding burn on the cord side and the wiring on the inside was toasted about 1-2" back also. So needless to say, I now have a new Smart Plug installed. I still have to find the time to clean all the wiring back (cable ties etc.) but I've got power back to the boat and the charger was doing it's job again. Unfortunately, we got one complete discharge of the house battery as I had left the airhead fan on and also had the parasitic drain of the stereo.
 
Most common cause of fires on boats is this plug. One item which will help is to be sure that the plug is locked into its ring--some are better than others --the large screw on metal cap is better. All power on the boat and at the pedestal needs to be off when you plug in. Often the plug connection becomes a little loose, then begins to arc, carbon builds up, and then increased resistance, more heat etc.

Good call--and good to replace!
 
David,

I changed the boat end plug and receptacle to the "Smart Plug" last year and found the instructions that came with the kit to be very complete and easy to follow. Hardest bit was physical access to the existing receptable(in my case).

Well worth the money for peace of mind if your boat is left on shore power for long periods.

M
 
Anna Leigh":nok7t7zp said:
Was the changeout pretty straight forward?
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Dave,

As Merv points out, it was pretty easy. The surface to which it is mounted is pure fiberglass and the hole that was cut previously for the Marinco connector is almost large enough for the new connector. The new connector is not round but rather has five sides. I used a dremel tool to remove just a little fiberglass at the bottom of the previous circular cut to create a flat area. Just an 1/8" or so was enough to get a snug fit. Since the Smart Plug connector is a 4 hole pattern and the Marinco is 3-holes, none of the previous holes line up or are useful in anyway.

The Smart Plug has a large gasket that will cover the previous holes and the parts of the round hole that aren't needed if one were installing new. E.g. on a new install, you'd cut the hole to the shape of the plug. Since it was just fiberglass, I filled the old holes with some 4200. As I've always had bad luck putting screws into fiberglass (cracking as I never quite get the pilot hole the right size) and as I had access to the back side of the hole, I through bolted the connector. 1.25" 8-32 SS machine bolts plus stainless nylon insert lock nuts on the back side hold in on there tightly. The biggest PITA is getting inside the hanging locker area on the boat to route the wiring etc. Of course, you want to connect the wiring to the receptacle prior to installing it as it would be a REAL PITA to try and do it afterward.

I was able to re-use the old cord by just cutting the end off of it and putting a new plug on. The Smart Plug has a long rubber tube through which the cord passes. The install kit comes with a plastic funnel shaped install tool that lets you feed the cord through this tight rubber fitting. If you follow the directions and apply a "liberal" coating of soap, it goes together pretty easily.
 
rogerbum":6be6ednj said:
As I've always had bad luck putting screws into fiberglass (cracking as I never quite get the pilot hole the right size) and as I had access to the back side of the hole, I through bolted the connector.
Click to expand...

I guess I'm not the only one! Even though I know it, it always takes me a few tries to purposely drill a pilot hole that is so close to the final screw size! And then I'm still not thrilled about the connection it makes. So like you, I through fasten if possible (or use some other alternative to the "pointy screw in fiberglass" connection).
 
I made a cable for our Honda gen use. It's pretty straight forward and the only special tool you'll need it a good quality wire [insulation] stripper.
 
Mine was even easier than Roger's as the orginal receptacle had the same hole size(s) as the Smart Plug and the orginal rigger was even "smart" enough to allow enough slack wire to pull the whole assembly out and get at the rear end. Otherwise I would have been looking for a 1'6" Gnome with fitted screwdriver protheses :-)

M
 
OK, I have seen these advertised but someone please enlighten me -- what good does it do to have a Smart Plug power cable when visiting a marina with the old style connectors?

Warren
 
Warren you only have the new plug on the boat side of the cable. Your dock side plug will remain the same. So if the dock side plug arcs and catches fire the dock will burn and then fall on your boat. That way the marinas insurance is writing the check and not you.
 
Now I understand! :roll:

starcrafttom":xrb73aqn said:
Warren you only have the new plug on the boat side of the cable. Your dock side plug will remain the same. So if the dock side plug arcs and catches fire the dock will burn and then fall on your boat. That way the marinas insurance is writing the check and not you.
Click to expand...

Seriously, it is looking a lot more attractive now.

Warren
 
Captains Cat":105lmy42 said:
Ordered one from Jamestown Distributors yesterday for about $120 plus shipping.
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Are you sure you got the "kit" for $120 and not just the inlet? When I just checked it was $191 for the kit with the inlet AND plug.
 
When we're home, we plug our boat into a 20amp circuit. I bought a second Smart Plug and made a short pigtail to a standard male plug... we can plug in there without having the heavy 30 amp cord in the cockpit or across the dock. A decent outdoor extension cord is much easier to handle, and we just leave it on the dock while we're out day-tripping.

The Smart Plug seems to be a good upgrade from the standard 3-prong marine plug.
 
A trick I've heard of for dealing with screws in fiberglass to prevent cracking-

After drilling the hole, get a larger bit and with the drill going in reverse, run the larger bit over the hole. It takes off some of the gel coat, and is supposed to help with spider cracks.
 
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