Pin and sleeve connectors for 30a shore power

[s/v Jedi]

Y’all efforts to whitewash the horrible 120V30A outlets and discredit the Smartplugs are futile. It was all tried before and it was all BS.

Even with the best products available, if you push a corroded wire in a terminal then it’s gonna burn. All those examples are from bad installations and incompetence.

As so often, a very good article from Rod Collins is available on this subject: https://marinehowto.com/shore-power-...tplug-vs-1938/

[Jammer]

Originally Posted by thinwater

Is the problem the twist lock, or that they are 20-30 years old and poorly maintained? I'm also guessing ABYC and NEC are waiting to see about the failure history of Smart Plugs over 20-30 years. The population is still rather small and they are new.

This. I am confident that new smartplugs outperform old twistlocks, but that is very small beer. For things like this there is no substitute for actual field experience over a period of years.

A fact to consider is that the NEMA twist-lock series is widely used as an indoor connection means for portable equipment that requires 3 phase power. These connectors differ from shore power plugs only in the number of blades and the way they are keyed. The smaller 20 amp 120v version is widely used for stage lighting. Though not perfect these connectors perform adequately indoors as do the relatively similar nonlocking versions, in widespread use up to 50 amps for household ranges and dryers as well as various commercial and industrial single-phase uses.

Originally Posted by wholybee

No doubt, the smartplug is better. But I think the failure rate of a newer, properly installed and maintained twist lock is actually rather low. Just my gut without any real data. I have personally seen a handful of boats burn at the dock, and all were no surprise, in terrible shape, with the owner doing their own shoddy work. I don't blame the twist lock as the reason for any of those fires, even if the receptacle is where it started. And smartplug isn't perfect either. There was an unfortunate sailor on here that lost his boat to a freshly (about 1 year iirc) installed smartplug.

Any high-current pressure connection can fail, including intrinsically more reliable ones like lugs bolted to a busbar.

A properly designed plug and receptacle system would use flame retardant materials and be designed so that the connection would fail, disconnecting the load, before the molten mess got hot enough to ignite the surrounding fiberglass.


My interest in pin-and-sleeve is based on the fact that they are already widely used outdoors including in marine environments, and seem to enjoy a good reputation. The only problems with them are that they are big and expensive.

[Jammer]

As a separate thought experiment, I've considered adding a temperature sensor to the shore power connection (with any type of connector) with an Arduino or something to indicate when heating is occurring and open a remotely located contactor to disconect the load when it is excessive. I believe SmartPlug tried something like this for a while but was trying to fit it all inside the inlet, which left them with an auto-reset thermal breaker that did not pass regulatory muster. (Because auto-reset breakers pose a number of safety problems of their own, including surprise energizing of circuits posing a hazard to electricians)

[Celestialsailor]

It would be interesting to know what type of connections are used in Aerospace. I worked in the industry but only in R&D and manufacturing. I would wager the stuff they sent up on the shuttle was bullet proof.

[thinwater]

Originally Posted by s/v Jedi

Y’all efforts to whitewash the horrible 120V30A outlets and discredit the Smartplugs are futile. It was all tried before and it was all BS.

Even with the best products available, if you push a corroded wire in a terminal then it’s gonna burn. All those examples are from bad installations and incompetence.

As so often, a very good article from Rod Collins is available on this subject: https://marinehowto.com/shore-power-...tplug-vs-1938/

NOT trying to discredit. Answer this:

Is smart plug list as an acceptable type for shore power pedestals in the NEC? A simple question. I could not find the answer on the web site.

I believe Rod Even mentions this: "... such as UL, NEC, NFPA, NMMA & the ABYC should all be ashamed that they continue to allow this standard to continue in the marine environment."

My point is that you will still have a twist lock at the dock for decades at least.

And there is always the matter of maintenance. For example, the plugs on my boat, pedestal AND home have all been replaced. I've replaced many of my mom's and daughters, as they become worn. Like the bedding on deck fittings, you can either wait until they fail or take care of them when they show signs of wear. Nothing is forever.

I also doubt they can be required by code with only one manufacturer. Not happening.
And then there will be the ugly transition phase, where most of the boats have twist lock and will have to use adapters. That will cause some problems. And would you want to switch your marina to Smart Plug and have everyone complain? Probably not.

So by all means, change your boat-side plug. But I think the pedestal change-over will come after I am dead.

[s/v Jedi]

Originally Posted by thinwater

NOT trying to discredit. Answer this:

Is smart plug list as an acceptable type for shore power pedestals in the NEC? A simple question. I could not find the answer on the web site.

I believe Rod Even mentions this: "... such as UL, NEC, NFPA, NMMA & the ABYC should all be ashamed that they continue to allow this standard to continue in the marine environment."

My point is that you will still have a twist lock at the dock for decades at least.

And there is always the matter of maintenance. For example, the plugs on my boat, pedestal AND home have all been replaced. I've replaced many of my mom's and daughters, as they become worn. Like the bedding on deck fittings, you can either wait until they fail or take care of them when they show signs of wear. Nothing is forever.

I also doubt they can be required by code with only one manufacturer. Not happening.
And then there will be the ugly transition phase, where most of the boats have twist lock and will have to use adapters. That will cause some problems. And would you want to switch your marina to Smart Plug and have everyone complain? Probably not.

So by all means, change your boat-side plug. But I think the pedestal change-over will come after I am dead.

NEC covers shore side and they do not specify which brands are allowed and which not afaik. They specify requirements that products need to meet. If you think that Smartplug does not meet requirements, then I recommend you ask them

What Rod wrote is that he would rather see that the twist connectors are banned and I agree, they should be. Thing is that they meet the requirements so that says everything about how worthless those standards are on that front.

[thinwater]

NEC and NEMA do specify the plug style. Yes, they do, for compatibility, I presume. You can look it up. Based on my reading, no other plug styles are permitted. For example, a 15A or 20A plug with waterproofing and retention equivalent to either twist-lock or Smart Plug would not be permitted. Neither are pin-sleave types. Only these specific styles.

Interestingly, Smart Plug is not on the ABYC list either (unless it has changed very recently, and I think Smart Plug would talk it up). This has been discussed, but I believe it is still in limbo.

A lot of emotional statements. I'm just stating standards in the rule book. I'm not sayin' it's right or that it makes sense. Read that last sentence twice, if you must. I am NOT judging.

From ABYC E-11

[tanglewood]

Originally Posted by thinwater

NEC and NEMA do specify the plug style. Yes, they do, for compatibility, I presume. You can look it up. Based on my reading, no other plug styles are permitted. For example, a 15A or 20A plug with waterproofing and retention equivalent to either twist-lock or Smart Plug would not be permitted. Neither are pin-sleave types. Only these specific styles.

Interestingly, Smart Plug is not on the ABYC list either (unless it has changed very recently, and I think Smart Plug would talk it up). This has been discussed, but I believe it is still in limbo.

A lot of emotional statements. I'm just stating standards in the rule book. I'm not sayin' it's right or that it makes sense. Read that last sentence twice, if you must. I am NOT judging.

From ABYC E-11

ABYC allows pin and sleeve connectors too. See figure 13 in the latest E-11 standard.


We all hate the 30A twist lock, bit let's talk about the practicality of changing it on the marina pedestal side.


First, it will never be changed to a Smart Plug. No standards committee would ever standardize a proprietary connector unless the maker completely opened the design, granted license to all patents, etc. And even then, to standardize on something that only one vendor is making... It just won't happen.


The far more sensible and likely change would be to the IEC pin & sleeve connectors. To me this would be a welcome change, adopts an existing standard, and one where there is a ready supply chain.


Then the question is how to transition everyone over to the new plugs & cords. Do you give marinas a cut over date by which they need to change? That's a big cost to a marina. And what about the transition period? Will boaters be required to carry adapters so they can plug into either type outlet? Or will marinas be required to provide adapters?


All in all it would be pretty ugly. Big changes like this - switching to RCD dock outlets is an example - typically trigger when there is a new build or significant upgrade to an electrical system. I have never heard of a required retrofit.

[s/v Jedi]

Originally Posted by tanglewood

ABYC allows pin and sleeve connectors too. See figure 13 in the latest E-11 standard.


We all hate the 30A twist lock, bit let's talk about the practicality of changing it on the marina pedestal side.


First, it will never be changed to a Smart Plug. No standards committee would ever standardize a proprietary connector unless the maker completely opened the design, granted license to all patents, etc. And even then, to standardize on something that only one vendor is making... It just won't happen.


The far more sensible and likely change would be to the IEC pin & sleeve connectors. To me this would be a welcome change, adopts an existing standard, and one where there is a ready supply chain.


Then the question is how to transition everyone over to the new plugs & cords. Do you give marinas a cut over date by which they need to change? That's a big cost to a marina. And what about the transition period? Will boaters be required to carry adapters so they can plug into either type outlet? Or will marinas be required to provide adapters?


All in all it would be pretty ugly. Big changes like this - switching to RCD dock outlets is an example - typically trigger when there is a new build or significant upgrade to an electrical system. I have never heard of a required retrofit.

I see 100A IEC connectors on Florida docks. I also saw 16A IEC connectors on docks in for example Panama, mixed with the 30A and 50A twist lock connectors.

[s/v Jedi]

FYI..

[thinwater]

Originally Posted by s/v Jedi

FYI..

Thanks! That was my question. I must have an old copy.


Ironically, the tighter Smart Plug holds on to the IP, the fewer they will sell. Common with inventions that only prosper when they become standard or widespread. Betamax comes to mind.

[thinwater]

Originally Posted by s/v Jedi

FYI..

But only 60A and up. In fact, I did see those, but they were not relevant to my world. I think I have seen them, along bulkheads for mega-yachts. And of course, in industry (common in places I have worked--I've even speced them).


I posted only figure 12. Figure 11 is to 120V and also not relevant to shore power.

[s/v Jedi]

You can’t change the outlets in the dock pedestal unless you own them but you can change the inlet and plug at your boat. At the shore end, if there are no IEC connectors, use the 120/240V 50A outlet which is much better than the 30A 120V outlets. Just connect to L1 and N and ignore L2.

[rslifkin]

The image showing the NEMA connectors shows one of the big reasons the 50A SS-1 and SS-2 connectors are more durable and make better contact than the L5-30 and other smaller twist locks. They've got that big, beefy locking ring around the outside, rather than relying solely on the pins to do the locking part and hold the weight of the connector.

[Dockhead]

Originally Posted by Celestialsailor

I will agree that a solution should be found for the twist locks.

That solution is a trash can.