Another power plug mishap.....

[rslifkin]

24 degrees rise at full rated load isn't necessarily concerning. As long as you're staying below the temperature rating of the wire insulation, connectors, etc. it's ok. Of course, more temperature margin is better. But slight warmth from a cable or connector at rated load isn't inherently concerning.

 

[Redhook98]

I have dual 30-amp connections on the forward side of my Portuguese Bridge, on both side (for ease of running cables when docked at other places). Exposed to rain and heavy weather, but properly covered when not in use. they are the Perko SS Screw-cap type. No fire alarm for that area. The inside area that was scorched in the pics is inside the double bulkhead of my P-Bridge.

 

[diver dave]

24 degrees rise at full rated load isn't necessarily concerning. As long as you're staying below the temperature rating of the wire insulation, connectors, etc. it's ok. Of course, more temperature margin is better. But slight warmth from a cable or connector at rated load isn't inherently concerning.

I'd like to know the metal temperatures. ANd, realize that it's plastic holding the metal prongs directly. THe OP is lucky. I see flamed paint, at least, and plastic boats burn like crazy. (is that plywood on the interior?) I was on the fence with NEMA before, but this is quite a departure from safe, long lasting electrical equipment for a tough environment.

Further note: in homes, all recepts need to be mounted in a fire resistant box, with very limited exposure to flammable material (no wood, or flame rated plastic, etc). As we all know, older boats can be a minefield of issues in this regard. A 30A boat side recept mounted in FRP would give me pause.

 

[Redhook98]

I'd like to know the metal temperatures. ANd, realize that it's plastic holding the metal prongs directly. THe OP is lucky. I see flamed paint, at least, and plastic boats burn like crazy. (is that plywood on the interior?) I was on the fence with NEMA before, but this is quite a departure from safe, long lasting electrical equipment for a tough environment.

Further note: in homes, all recepts need to be mounted in a fire resistant box, with very limited exposure to flammable material (no wood, or flame rated plastic, etc). As we all know, older boats can be a minefield of issues in this regard. A 30A boat side recept mounted in FRP would give me pause.

It is fiberglass over wood. Boat is a 1979.

 

[syjos]

It is fiberglass over wood. Boat is a 1979.

Install the shore power inlet on a stainless plate with a metal box on the backside.

 

[sunchaser]

Based upon the OP's stated (and unstated) loads he was tickling 30 amps. Is a smart plug capable of taking full rated amps in a safer manner than a standard Marinco or Hubbell?

 

[MacPhid]

If the vessel is 40 years old I would think it’s just as likely the overload was at the terminals where the boats internal AC wiring joins to the 30A plug inside the boat. The pictures show that is a possible scenario. While we check the removable cord connections regularly, checking the interior connections is also important.

James

 

[hytedin]

Forgive the question,but I currently have two 30amp twist lock coming into the boat.

Can I replace them with a 220v 50amp and split the feed at the inside portion of the 50amp connectors to the two 110v 30amp feeds going to my panel?

Ideally, I would like to avoid refeeding the panel and splitting the 220v at that side—rewriting essentially.

 

[rslifkin]

Forgive the question,but I currently have two 30amp twist lock coming into the boat.

Can I replace them with a 220v 50amp and split the feed at the inside portion of the 50amp connectors to the two 110v 30amp feeds going to my panel?

Ideally, I would like to avoid refeeding the panel and splitting the 220v at that side—rewriting essentially.

Yes, you could do that. Or you could do 2x 50A 125v inlets as well, although then you need 2 cords that are only slightly lighter. I've got that setup simply because it's how my boat was built and I've got no reason to change it.

In either case, carry the necessary adapters to hook up to 2x 30A, 2x 50A 125V (uncommon) or 1x 50A 125/250V. I carry a Y adapter to split a 50A 125/250 into 2x 50A 125V as well as a pair of pigtails to use 30A outlets. The adapters you'd want would be different if you have a single 50A 125/250 on the boat.

If you upgrade to 50A inlets, you need to either run 6ga wire (instead of the 10ga used for 30A) to the 30A main breakers (and make sure any transfer switch can handle 50A). Or add a set of 30A breakers right after the inlets (with 6ga between them and the inlets). That way you don't have any inadequately protected wiring.

On that same note, having 50A inlets on the boat also avoids another common safety trap. Adapting a 50A 125/250 dock outlet to a pair of 30A boat inlets is unsafe unless you have a pair of 30A breakers in the splitter / adapter. The 50A dock breakers won't adequately protect a 10ga / 30A shore cord or the boat inlets or the boat wiring from the inlets to the main breakers.

 

[psneeld]

Yes, but 99% of transient docks along the ACIW seem to be 125/250V 50A so that is what I went with to keep it to dragging a single cord.....the others are twin or single 30s.

There are pre made panels to aid in the swap and have several onboard setups.

 

[hytedin]

Yes, you could do that. Or you could do 2x 50A 125v inlets as well, although then you need 2 cords that are only slightly lighter. I've got that setup simply because it's how my boat was built and I've got no reason to change it.



In either case, carry the necessary adapters to hook up to 2x 30A, 2x 50A 125V (uncommon) or 1x 50A 125/250V. I carry a Y adapter to split a 50A 125/250 into 2x 50A 125V as well as a pair of pigtails to use 30A outlets. The adapters you'd want would be different if you have a single 50A 125/250 on the boat.



If you upgrade to 50A inlets, you need to either run 6ga wire (instead of the 10ga used for 30A) to the 30A main breakers (and make sure any transfer switch can handle 50A). Or add a set of 30A breakers right after the inlets (with 6ga between them and the inlets). That way you don't have any inadequately protected wiring.



On that same note, having 50A inlets on the boat also avoids another common safety trap. Adapting a 50A 125/250 dock outlet to a pair of 30A boat inlets is unsafe unless you have a pair of 30A breakers in the splitter / adapter. The 50A dock breakers won't adequately protect a 10ga / 30A shore cord or the boat inlets or the boat wiring from the inlets to the main breakers.

Thank You!!!

 

[Redhook98]

If the vessel is 40 years old I would think it’s just as likely the overload was at the terminals where the boats internal AC wiring joins to the 30A plug inside the boat. The pictures show that is a possible scenario. While we check the removable cord connections regularly, checking the interior connections is also important.

James

Those connections were made within the past 4-5 years. The man who restored it used shore power cables from the back of the plugs to the panels and the connectors were new (at the time). He used copious amounts of de-ox grease on everything. I am in a brackish water area so we do not have a real salt issue here. I am chocking this one up to a bad connection and am currently going through all the rest of them now.

 

[caltexflanc]

And 100% of every failure I have seen was probably corrosion/bad connection in the plugs, not because of their ratings...not the wires unless damaged and not the CBs

I'll pile on in agreement here. I have only read the first page of thread.

Your shore cords are an item that need checking and preventative maintenance. Checking is simple, put your hand on the connecter when you a running power through them. They should be cold, no sign of warmth. Run your hand a long the last three or four feet of cable too. If you feel any warmth, time to pull them apart and see what's up.... immediately. Also check temps of the connections inside the boat.

Same goes for most of your electrical system to a large degree. This one is more vital and yet easiest.

It's always been odd to me how obsessed people get about using shore water, but blithely hook up to shore power and never bother to check it let alone maintain it, just like they don't on their plumbing and bilge pumps.

 

[syjos]

I contacted Marinco and asked what the continuous rating for their 30 amp inlet and their reply:

Thanks for contacting Marinco Technical.

Marinco inlets are rated for 30A continuous.

David Freeman

Technical Service

800.307.6702 direct

800-799-3779 fax

technical@marinco.com

N85 W12545 Westbrook Crossing

Menomonee Falls, WI 53051

www.marinco.com www.mastervolt.com

 

[Olebird]

The inexpensive, non contact thermometers (Horrible Freight) are really handy. When we are over nighting, I try to use it every night to check shore power connectors, panels, and any high current appliance connection for abnormal temp rises. (will also check the adjacent pedestals and neighbors power cord connections where convenient from the dock)
CorrosionX on the contacts & 303 on the vinyl cord and fenders every 6 mos.

 

[catalinajack]

It has twenty (20) times more contact area. Get a smart plug cordset and sleep well at night. Some boats, as mine does, have the boat outlet in knuckle-busting locations with the added frustration of having to get the plug oriented just right to push and twist. A smart plug is simply push and click and you get a connection that just won't loosen. Plus, the jacket on a smart plug cordset makes it remarkably easy to handle and coil, even the 50-amp, 50-footer. Sure, you can maintain the old style but even brand new you will have 1/20 of the contact area. The shoreside connection is still the old style but a problem there is much less likely to burn down your boat. I check my connections frequently. Never have they been any warmer than the ambient temperature.

I run 30 amps from shore power a lot and have never had a burnt or melted plug. No furnace so we run electric heaters during the winter.

I examine and clean the prongs with electrical contact cleaner monthly. I also spray the cleaner into the female cord plug openings while holding the prong with the openings facing down to drain. A Scotchbrite pad is sometimes used for thorough cleaning of the male prongs.

The wiring from the shore inlet to the breaker and panel is #8 instead of the standard #10. In order to mitigate any possibility of the area around the inlet getting hot or burning, the inlet is mounted on a flush mount steel electrical box that is enclosed on the back side to contain any flames.

During the winter when we are away for couple months and heater use is high, I use a shore power cord with three ring terminals instead of the female plug and direct connect it to a terminal block inside the electrical box.

I'm in the process of installing a temperature sensor on the back side of the shore inlet wired to a solenoid that will open when the temperature gets to a certain point. I have to experiment and see what the high temperature open point will be.

The first generation Smart Plug had the safety feature of opening the circuit when the inlet became hot. That feature was discontinued since the breaker they used would reenergize automaticaly when the temperature dropped introducing a safety hazard.

The lack of a high temp cutoff on the newer Smart Plugs sort of reduces the safety aspects. It still has positive clamping and more contact surface area than standard plugs. But the contact area on Smart Plug still needs to be kept clean.

 

[bayview]

Doesn't matter what plug/socket you use if it is in a damp salt water environment and not opened and inspected regularly there will be corrosion and problems.

 

[sunchaser]

It has twenty (20) times more contact area. Get a smart plug cordset and sleep well at night. Some boats, as mine does, have the boat outlet in knuckle-busting locations with the added frustration of having to get the plug oriented just right to push and twist. A smart plug is simply push and click and you get a connection that just won't loosen. Plus, the jacket on a smart plug cordset makes it remarkably easy to handle and coil, even the 50-amp, 50-footer. Sure, you can maintain the old style but even brand new you will have 1/20 of the contact area. The shoreside connection is still the old style but a problem there is much less likely to burn down your boat. I check my connections frequently. Never have they been any warmer than the ambient temperature.

I'm not sure this specific issue as raised by the OP should end with merely buying a smart plug setup to solve the described problem. It would seem:

• The 30 amp circuit was overloaded
• The shore connection on the boat side was redone by the previous owner using 30 amp cord set wiring to the breaker panel
• A really good marine electrician may be useful to insure this vessels wiring is up to snuff

 

[psneeld]

It's not the surface area that matters, it's the low resistant, contact area that does.

If the old style plugs are adequate, and are kept clean and the connection tight ( like an older 50A seems to maintain)...then 20X the area is 20X more than really required.

If 20X the area is slightly corroded, it may actually be worse than a clean old style.

Like many boat issues....PM is just as important as the equipment....as we know of brand new boats catching fire, sinking, etc..

Personally I am leaning towards hard wired power cords as the best option.

 

[Codger2]

I can appreciate all the suggestions relative to a safe hook up of shore power to your boat but that isn't the reason I switched to SmartPlug. Many years ago when my first big boat (OffShore 48)was purchased, The old connection to the boat was a real PITA! The threads on the boat receptacle & the connecting ring were too fine, resulting in numerous cross threading results. When SmartPlug came on the scene with a connection that was not only more secure (and no threads) but also had better contact, I pulled the trigger and bought one which I installed myself.

Note the side catches that lock the plug in place and the cam action on the cover which guarantees a secure connection.

 

[psneeld]

The locking tabs on a 50A 125/250V plug is pretty secure, Waayyyy better than hanging from the prongs of a 30A. As long as a bit or "good" twist is induced, I think a 50A 125/250V plug would be as secure as a snap in Smart Plug.

 

[syjos]

The Marinco 30 amp cordsets and inlets were redesigned a while ago to the Easy Lock system. The ring locks the cord set to the inlet in just 1/8 of a turn allowing easy, quick hookup. Locking tabs on the ring engage slots built into all current Marinco inlets making the connection solid and elliminate movement of the plug.

Marinco cordsets come with both the Easy Lock ring and a threaded ring for older inlets.

 

[psneeld]

The Marinco 30 amp cordsets and inlets was redesigned a while ago to the Easy Lock system. The ring locks the cord set to the inlet in just 1/8 of a turn. Locking tabs engage slots built into all current Marinco inlets. The connection is solid and does not allow movement of the plug.

Marinco cordsets come with both the Easy Lock ring and a threaded ring for older inlets.

My apologies to 30A plugs if they truly are secure now at both ends.

I left for the 50A crowd and never really looked back except for all my friends that still dont have the Easy Lick system and are still burning up plugs,

 

[syjos]

Marinco also has the EEL (Easily Engaged Lock) system for cord sets. It uses a jaw-clamp design providing one-handed operation and a secure waterproof seal which completely eliminates the need for a locking ring

 

[diver dave]

...

Personally I am leaning towards hard wired power cords as the best option.

That is my mindset also. Just need to secure the cord end/shore connector someplace off the weatherdeck. Or use the reel with a door.

 

[syjos]

My apologies to 30A plugs if they truly are secure now at both ends.

I left for the 50A crowd and never really looked back except for all my friends that still dont have the Easy Lick system and are still burning up plugs,

Only the inlet (female) end has been redesigned. The pedestal (male) end of the Marinco and Smart Plug use the standard three pin twist-type connector.

Most of the issues at the pedestal connection has not been addressed by either company. A burned plug and socket there will not cause a fire since most pedestals are metal.

The female receptical on most pedestals are oriented down making it hard to see so you may inadvertently plug your shiney new cordset into a previously burned receptacle causing damage to the male prongs.

I use a sacrificial adapter made of a short length of cord with a male plug on one end and a female plug on the other. I plug the adapter into the pedestal and plug my shore cord into that to protect the male prongs on the cordset.

 

[syjos]

Personally I am leaning towards hard wired power cords as the best option.

I agree. I hardwire the cord at the inlet during winter when the boat doesn't get used often and the heater and dehumidifier are being used.

 

[Comodave]

Even with the new design by Marinco it still does not address the small contact surface area. People will argue that it is fine but it still has very little contact area for 30 amps. Smart plug is much better with 20 times the contact area. More contact area is always better for current carrying. It has less resistance and therefore less heat.

 

[psneeld]

Assuming "more" has less resistance for the requirements. Do we know that the current plugs don't have enough plus a safety factor?



I doubt manufacturers start with a surface area that they know is inadequate.


Personally I wouldn't touch a plug without 30X more area.

 

[rslifkin]

More surface area won't hurt, but secure locking and being generally durable is a bigger concern. That's my big issue with the L5-30 connectors. They're just not very durable and particularly at the non-boat end (without the locking ring), they don't engage solidly. And even at the boat end, they take a lot of abuse over time without the collar to force them to go in straight enough.