50amp shore power question

[Clipper4730]

Hi Folks, need to replace our 50amp shore power cable and had a few questions. Do we need tinned wire? Looking at a Marineco review someone said it was not tinned and only had a temp rating of 140f. I can’t seem to find any that are tinned or have a higher temp rating. Does it really matter. We bought a “budget” cable years ago and seems to have been working fine just not long enough. AmpUp has a 75’ 50amp cord for $499, go2marine has a Marinco one for $795.
Thoughts

As always thanks in advance

[GreenWave]

Marinco cords are not tinned wire- at least not any of the ones that I opened up. Thus in my opinion, you can buy the lesser priced versions. Best thing to do is spray corrosion X or equivalent on each connection end and keep it clean and dry.


Or change to using Smart Plugs which are much better config. I have been happy with that transition.

[Clipper4730]

Thanks for the info. I’ll check out the Smart plugs. To be honest don’t even know what tinned means just saw it in a review.
Thanks

[GreenWave]

Tinned wire will have a silver look to it as opposed to copper color for untinned. You can buy the smart plugs kit to basicallt chop off the boat end of your existing power cord and then replace the on boat receptacle as well.

[Jammer]

The quality of premade ones is mediocre, especially for the price. Usually they use a thermoplastic jacket that does not hold up well. I like type SJOOW (lighter and easier to store) and SOOW (heavier but indestructible) cable. SOOW and SJOOW are both rated for 90 degrees C. and have a synthetic rubber (CPE) jacket that is extremely tough. The jacket on the SOOW is thicker, as is the insulation on individual conductors, which is why it is heavier and bulkier.

It is hard to find tinned cable in sizes large enough for 50a.

You would have to purchase and install the ends separately, or have an electrician do it for you. They are an insignificant part of the overall price for what you're doing -- the money is in the cable itself.

I have used SOOW for theater lighting and portable agricultural equipment. It isn't completely bulletproof but you have to run over it with a forklift or a loaded semi or something to damage it.

I am skeptical of Smartplug's claims but realize I am in the minority here. I don't know what kind of cable they use in their cordsets.

[rslifkin]

For a 50 amp connection I wouldn't worry as much about Smart Plugs. They're a massive improvement over the L5-30 connector used for 30A / 125V shore power. However, the NEMA SS-1 and SS-2 connectors used for 50A power (SS-1 for 3 wire 125V, SS-2 for 4 wire 125/250V) are already dramatically better than the L5-30 and the Smart Plug is a much smaller improvement.


If you desire to build your own cord or anything, 50A cords typically use 6ga wire.

[sailingharry]

I can't bring myself to cut off a crappy plug that meets an open industry standard that is priced by competition, and install a closed/proprietary plug (that is priced accordingly), no matter how much better it might be.
But, it raises a question. If I were to cut off the "standard" plug (or even both) and install a rogue alternative, is there an industry standard plug that is superior? Maybe an RV standard? Or an industrial plug, maybe pin and sleeve?
Currently, I have my inverter set to limit incoming current to 15A, so it's really a non issue, but always thinking.

[s/v Jedi]

Originally Posted by sailingharry

I can't bring myself to cut off a crappy plug that meets an open industry standard that is priced by competition, and install a closed/proprietary plug (that is priced accordingly), no matter how much better it might be.
But, it raises a question. If I were to cut off the "standard" plug (or even both) and install a rogue alternative, is there an industry standard plug that is superior? Maybe an RV standard? Or an industrial plug, maybe pin and sleeve?
Currently, I have my inverter set to limit incoming current to 15A, so it's really a non issue, but always thinking.

The European plugs are superior. You need the 32A version for a 30A inlet.

I recommend to use the SmartPlug though. It’s even superior to the EU plugs.

[Fintry]

I don't have a problem with a manufactured cable that is bare copper and is, therefore, pretty well sealed, but I would not want make my own cable with untinned wire and new end fittings. Perhaps none of the commenters above have seen a shore cable with green (oxidized) wires reaching two or three feet in from the ends?


Current capacity depends heavily on the insulation. #6 is pretty heavy - I'd try to find #8 that is rated for 50A. Ancor's 105C boat cable (which you can't use for shore power) will do 50 A with #10 conductors.


Jim

[s/v Jedi]

Originally Posted by Fintry

I don't have a problem with a manufactured cable that is bare copper and is, therefore, pretty well sealed, but I would not want make my own cable with untinned wire and new end fittings. Perhaps none of the commenters above have seen a shore cable with green (oxidized) wires reaching two or three feet in from the ends?

Current capacity depends heavily on the insulation. #6 is pretty heavy - I'd try to find #8 that is rated for 50A. Ancor's 105C boat cable (which you can't use for shore power) will do 50 A with #10 conductors.

Jim

Whenever you replace the burned plug on a manufactured shore power cable, you do exactly that: a better plug onto a bare copper cable. If you worry about corrosion of the bare copper, then after freshly stripping the conductors, coat them liberally with dielectric grease before connecting them to the new plug. This will now outlive the rest of the cable.

[GreenWave]

When I changed two cords to Smart Plugs I did so because a) one of my cords was brunt at the pedestal end and the boat end, and b) the boat receptacle was also burnt. It was a disaster drive by. When I cut off the boat end I had to strip back 10 feet before I found clean copper wire. When I then converted one of my other cords it was a near total loss. I ended up with about 20 feet of wire which I kept for other use and then bought a new 50 foot cord and YES cut off the head for conversion.


Having said this- I am drinking the Smart PLug kool aid and I don't really care what cable they use. The plug is the difference. It is a tight seal and never even gets warm! I continually have to dry out my third Marinco plug. I plan to convert that soon.

[Jammer]

Originally Posted by sailingharry

But, it raises a question. If I were to cut off the "standard" plug (or even both) and install a rogue alternative, is there an industry standard plug that is superior? Maybe an RV standard? Or an industrial plug, maybe pin and sleeve?

Pin and sleeve, which Jedi refers to as a "European plug" upthread. But they are big and expensive, particularly in the waterproof inlet version, which is what you need on the boat end. There are some semi-proprietary riffs on the standard that are a little more compact, too. They give up the locking ring. I don't know how good they are.

[Jammer]

Originally Posted by Fintry

Current capacity depends heavily on the insulation. #6 is pretty heavy - I'd try to find #8 that is rated for 50A. Ancor's 105C boat cable (which you can't use for shore power) will do 50 A with #10 conductors.

I am skeptical of this approach. Even if the cable is rated for 105C, few connectors are. 8 AWG at 50 amps in a multiconductor cable is pushing it, IMO, though I've done it. 10 AWG at 50 amps in a multiconductor cable is unwise no matter what the tables say. Shore power is a continuous-duty application.

[rslifkin]

The other reason to stay with 6 AWG instead of 8 is voltage drop. Many docks already have plenty of drop at the pedestal under load, so if you've got a 50 foot shore power cord, I wouldn't want to down-size and make voltage drop concerns worse. If it's a short cord then adequately rated 8 AWG might be fine.

[GordMay]

Per NEC Table 400.5: Allowable Ampacity for Flexible Cords and Cables
➥ https://up.codes/s/ampacities-for-fl...rds-and-cables

The maximum permitted ampacity for a 2 Conductor #10 AWG cord is 30 A.
A 50A cord requires #6 AWG conductors [minimum].