Proper care of shore power cables

[Kuncicky]

The old trawler which I bought and am trying to resuscitate came with a set of shore power cables. They are in awful shape. Corroded, burn marks on the connectors, and also just look bad. So I spent some money to buy some new 30-amp cables (the boat uses two). These things are not cheap!


So I want to take proper care of them. I thought about putting some 303 on, to maybe keep the UV from making the bright yellow color turn into a sickly gray color. But not sure what to do about the corrosion and burn marks. Any suggestions will be welcome. Keeping the boat and cables out of the sun is not an option, unfortunately.



Thanks,
Bill

 

[Redhook98]

Plug them in properly and use dielectric grease. Can get covers for them, but they wear out quick.

 

[The Brockerts]

Covers that don't wear out quickly. Covers with 10 year warranty, Sunbrella® fabric

https://www.allamericanpowercordcover.com/

The Brockerts

 

[Comodave]

The L5-30 plug was designed in the 1930s. It doesn’t make good contact so resistance causes heat. Therefore the melted and burned connectors. A better solution is a Smart Plug cordset and inlet. They have about 20 times more contact area than the L5-30. But if you are going to keep the L5-30, then inspect both the cord plug and the inlet for heat related damage. Any sign of melting and it should be replaced. If you get new cords and the inlet has burn or melted area then it will transfer onto the new cord and damage the plug. So inspect them both and replace the damaged one quickly before it ruins the new cord or vice versa. Keeping the cables inside a cover will help them last longer. Don’t use any solvent like acetone to clean them.

 

[dhays]

Two good suggestions.

I use dialectic grease on both he dock-side and boat side connections.

My current boat has the odd 50a/125v connector. It is very solid so less concern than with the tradition 30a/125v connectors. On my last boat with had the 30amp plugs, I replaced the boat side with a SmartPlug. It was well worth the small investment.

 

[FF]

Its a PIA , but cut off at least a foot of wire any time the plug gets dunked in sea water.


Stuff happens!

 

[twistedtree]

I'll just reiterate what I think has already been said...


If the boat end of your old cable was in tough shape, then the receptacle on the boat is surely is just as bad shape. That bad receptacle will trash your new cord, so be sure to replace the receptacle as well.

 

[Redhook98]

Its a PIA , but cut off at least a foot of wire any time the plug gets dunked in sea water.


Stuff happens!

The plug end is sealed. Should have zero water intrusion there if dropped in the water. Rinse with fresh water and bit of WD40, dielectric grease, and good to go. The socket end is supposed to be sealed also. But...... I would douche it out pretty good with WD40 and see how it reacts before snipping and replacing. Once you take the factory installed plug or socket off and replace with a non-sealed unit, you introduce another method for water intrusion.

I bypassed all this and went with Smartplugs some time back after my boat caught fire. (pics are in a previous thread from a year ago or so). Learned the hard way to make sure you do this right. The L5 plugs are not a no-go for me. Work well when properly taken care of and installed, but if you mess up, you could be in for trouble.

 

[wkearney99]

We've got a 50A cord fed from a cablemaster inside the boat. It's very convenient to not have to deal with storing the line when we travel. Just wind it in/out. But for the home slip I've wondered about the possibility of using a cord kept there. Our pedestal is not adjacent to the cable's outfeed on the boat and typically requires unspooling nearly the whole cord each time.

 

[Kuncicky]

The L5-30 plug was designed in the 1930s. It doesn’t make good contact so resistance causes heat. Therefore the melted and burned connectors. A better solution is a Smart Plug cordset and inlet. They have about 20 times more contact area than the L5-30. But if you are going to keep the L5-30, then inspect both the cord plug and the inlet for heat related damage. Any sign of melting and it should be replaced. If you get new cords and the inlet has burn or melted area then it will transfer onto the new cord and damage the plug. So inspect them both and replace the damaged one quickly before it ruins the new cord or vice versa. Keeping the cables inside a cover will help them last longer. Don’t use any solvent like acetone to clean them.

I'll quote just one response, but appreciate all of them. I didn't know about the dielectric grease, so ordered some from Amazon just now. I'll stick with the old-style plugs for now, since I just bought new cables. But if and when I have to get new ones, will definitely check out the smart plugs. So far as the cover, I have some old Sunbrella, and may be able to make something which will serve.


So thanks for all the good suggestions, from everyone.


Bill

 

[dhays]

We've got a 50A cord fed from a cablemaster inside the boat. It's very convenient to not have to deal with storing the line when we travel. Just wind it in/out. But for the home slip I've wondered about the possibility of using a cord kept there. Our pedestal is not adjacent to the cable's outfeed on the boat and typically requires unspooling nearly the whole cord each time.

Short Version: A dedicated home dock cord is worth it.

Long Version: As long as I’ve owned larger boats, I’ve always kept a power cord on the dock that stays there, and then keep a 50’ cord on the boat for use when traveling. One advantage to this is that the dockside connector only gets disturbed once a year for inspection and re-greasing. It also means that the cord is well secured to the dock to avoid any unintentional dunkings. Even when I used the SmartPlug, I made up two cords, one for the dock and one for the boat.

With my odd-ball 50/125 service, have to use a 30/125 -> 50/125 adapter almost all the time when traveling. 50/125 dock power is very rare. So that adapter stays connected to the traveling cord.

Strangely enough, my home slip happens to have 50/125 service. Before getting this boat, I had to use a 50/125->30/125 adapter to power my sailboats typical 30/125 service.

I was lucky enough to find a short 50/125 Marinco power cord on sale a few years ago. Normally they are ungodly expensive but this was reasonable and is perfect for my permanent dock cord as there is no excess cord laying around.

 

[dhays]

I'll quote just one response, but appreciate all of them. I didn't know about the dielectric grease, so ordered some from Amazon just now. I'll stick with the old-style plugs for now, since I just bought new cables. But if and when I have to get new ones, will definitely check out the smart plugs. So far as the cover, I have some old Sunbrella, and may be able to make something which will serve.

When I switched to the SmartPlugs on my last boat, I used the cords that I already had. One of them was almost new. I cut off the boat end of both and replaced it with the SmartPlug male ends. Changing the boat side receptacle was easy.

There are some very real advantages to keeping a power cord permanently at your home dock.

 

[Marco Flamingo]

I replaced my receptacle because I could see that there was some carbon, tiny "weld" marks, etc. I don't know what the contacts in my dedicated dock cord look like, but because I inheirited it with the moorage, I probably should be really suspect. It's plenty long enough to cut off a foot and get a new plug.

One of the things you can do to make the cord and receptacle last is to never plug it in with the dock circuit breaker on. You might think that everything is off on the boat, but plugging it in when there is a little draw from the boat will cause a spark (that you can't see) with resulting carbon or worse. Turn off the dock CB, plug in, walk back and throw the CB. Time well spent.

 

[ABfish]

I really like the idea of a dedicated cord for the home slip. Don't know why I never thought of that.

I have a Cablemaster as well, but having a short cord for the home slip would be even easier. Just unplug and put in the dock box.

 

[dhays]

I really like the idea of a dedicated cord for the home slip. Don't know why I never thought of that.

I have a Cablemaster as well, but having a short cord for the home slip would be even easier. Just unplug and put in the dock box.

I don’t even bother putting it in the dock box. If I did that it would mean removing the cord from the dock pedestal. The few times it is plugged and unplugged, the more wear there is on the plug and then I don’t have to regrease it as often. Just make sure the cord won’t accidentally fall into the water. I’ve never had a power cord go missing from the dock when I’ve been away.

 

[firehoser75]

Following a routine for both plugging and unplugging. Plugging in: all boat A/C breakers off. Shore pedestal breaker off. Plug in the boat end (inspect both boat recepticle and the cord end for signs of overheat damage). Plug in the pedestal end (inspect as before). Turn on pedestal breaker followed by the onboard main breaker. Look for reverse polarity and ensure the correct voltage. Turn on necessary circuits. Check amperage draw to ensure within good limits (eg. 20 amp or less sustained for a 30 amp system).

Unplugging: Turn off all boat loads including main breaker. Turn off pedestal breaker. Unplug cord from pedestal then the boat end. This will save any chance of arching due to power being on which will over time shorten cord life and prevent any chance of walking around carrying a live power cord.

Do not walk around a dock carrying a "live" cord end. It is a bad mix, electricity and water should you or the cord fall in (could be a swimmer or diver nearby, or you if you fall in).
Likewise, do not leave a cord lying on the dock (for those who leave a "home cord") with power on. This could be very dangerous if knocked into the water at the wrong time. Yes, the likelihood is probably low, but it is not good practise. Turn off the shore pedestal breaker at minimum and best to unplug so it is easy to tell power is off.

 

[C lectric]

I see people mishandling the cords when cooling/uncoiling.

Do NOT allow the prongs to flail or drop on the dock surface. That is the end I hold onto while coiling.

Benti pins make POOR contact and can be difficult to correct properly.

 

[localboy]

Following a routine for both plugging and unplugging. Plugging in: all boat A/C breakers off. Shore pedestal breaker off. Plug in the boat end (inspect both boat recepticle and the cord end for signs of overheat damage). Plug in the pedestal end (inspect as before). Turn on pedestal breaker followed by the onboard main breaker. Look for reverse polarity and ensure the correct voltage. Turn on necessary circuits. Check amperage draw to ensure within good limits (eg. 20 amp or less sustained for a 30 amp system).

Unplugging: Turn off all boat loads including main breaker. Turn off pedestal breaker. Unplug cord from pedestal then the boat end. This will save any chance of arching due to power being on which will over time shorten cord life and prevent any chance of walking around carrying a live power cord.

Do not walk around a dock carrying a "live" cord end. It is a bad mix, electricity and water should you or the cord fall in (could be a swimmer or diver nearby, or you if you fall in).
Likewise, do not leave a cord lying on the dock (for those who leave a "home cord") with power on. This could be very dangerous if knocked into the water at the wrong time. Yes, the likelihood is probably low, but it is not good practise. Turn off the shore pedestal breaker at minimum and best to unplug so it is easy to tell power is off.

Exactly my process. Nothing live until I want it live.

 

[Bacchus]

I have 2 - 30A inlets and when cruising carry 2 - 50 ft 30A cords and a 25 ft 30A cord and have the ability to run anything desired from one cord / inlet.
I would switch to Smart Plugs in a heart beat but don't want to lose the ability to join 2 50 fters or a 50 + 25 ft to reach a distant pedestal.
Also for those replacing molded plugs with new plugs you can fill the plug / housing with silicone caulk to keep moisture & water out of the " inner workings" pretty common on trailer plugs and its effective.

 

[Comodave]

I have 2 - 30A inlets and when cruising carry 2 - 50 ft 30A cords and a 25 ft 30A cord and have the ability to run anything desired from one cord / inlet.
I would switch to Smart Plugs in a heart beat but don't want to lose the ability to join 2 50 fters or a 50 + 25 ft to reach a distant pedestal.
Also for those replacing molded plugs with new plugs you can fill the plug / housing with silicone caulk to keep moisture & water out of the " inner workings" pretty common on trailer plugs and its effective.

Smart Plugs don’t stop you from extending the power cord with a second cord. Only the boat end and inlet are different. The dock end and any other power cords still have the L5-30 plugs. Go for the Smart Plug!

 

[Bacchus]

Smart Plugs don’t stop you from extending the power cord with a second cord. Only the boat end and inlet are different. The dock end and any other power cords still have the L5-30 plugs. Go for the Smart Plug!

Got that but if I convert the boat ends I can't join them for a longer one. I use all 3 as direct to boat in various situations. If I convert them no longer able to join them... need another 2-3 " extension" cords.
I suppose I could convert one and use it as a primary and leave others conventional?

 

[dhays]

Got that but if I convert the boat ends I can't join them for a longer one. I use all 3 as direct to boat in various situations. If I convert them no longer able to join them... need another 2-3 " extension" cords.
I suppose I could convert one and use it as a primary and leave others conventional?

Yes. That is exactly what I did for a while with my Sailboat. The power inlet for the boat was in the stern but the dock location made backing into the slip difficult. I needed an extension to reach the pedestal. I made one 50’ cord with a Smart Plug on the boat end and kept another cord with the standard connectors.

In your case you would just change over one 50’ cord end and leave the others as is.

 

[Hippocampus]

Any thoughts about how to easily check the integrity of the pedestal? We take a quick snap of the water and electric numbers to prevent overbilling but as long as we get power and no sparks with normal voltage on the panel generally don’t take it further. Some of them look real funky.

 

[backinblue]

Is dielectric grease of any use on power cables? I recently used some on a low power connection for thruster control that had become corroded and seems to work well at least so far. Just curious as I have limited experience with this stuff even though I have a lot of electrical/electronic experience.

 

[diver dave]

Grease reduces “fretting corrosion” by keeping oxygen away from the contact area. No oxygen, no carbon burning of the metal.
But note that grease wont fix a low contact area, worn out system.

 

[backinblue]

Grease reduces “fretting corrosion” by keeping oxygen away from the contact area. No oxygen, no carbon burning of the metal.
But note that grease wont fix a low contact area, worn out system.

I get that. I guess my question really is, if my shore power cables are in fairly good condition, would adding grease to the connections help them last longer? Assume they are normally plugged in but disconnected and reconnected weekly.

 

[diver dave]

IMO, yes. And its on my list as well. In fact, i have that grease on board and will do mine now[emoji122]

 

[rslifkin]

Any thoughts about how to easily check the integrity of the pedestal? We take a quick snap of the water and electric numbers to prevent overbilling but as long as we get power and no sparks with normal voltage on the panel generally don’t take it further. Some of them look real funky.

Checking for excessive voltage drop and no hot connections while under load should be a good check that it's at least working well enough.

 

[Hippocampus]

It’s easy to check for voltage drop. Don’t even need the multimeter. But how do you check for hot spots? Gunning it won’t seem to work unless you open up the access plates and the marina wouldn’t be happy seeing you do that. Also they sit in the sun so even a good one can be quite warm. I’ve resorted to ask the Dockmaster to check it out but sometimes they just ignore you “it’s fine”. Been told that’s a place fires start. You may have a perfect setup but wouldn’t a junky pedestal still be a risk?

 

[Comodave]

Yes, the pedestal is a fire risk. But with Smart Plugs you have moved the more probable fire risk off the boat and to the pedestal. I would much rather have a fire at the pedestal than onboard the boat.