Possible SmartPlug problem

dlochner · May 22, 2023

Sailm8 said:
While washing the boat I touched my SmartPlug and found it really hot. I unplugged it and found it goo rhad run out of one plug hole and it smelled burnt. I found charred wires so I replaced both the SmartPlug and the entire cord. I contacted the manufacurer but couldn't get a straight answer on operating temps. The load is the A/C unit that has been flawless but I had an A/C guy check it out and it passed. When I powered up the next morning it started at 77 degrees f and began to rise until I pniced and shut down at 130 degrees. I would like to know if this is the correct operating temp before I starrt checking all the wiring.
Additional info: The A/C guy found the amperage draw normal. The 130 degrees was not nearly as hot as when I found the red hot problem. The A/C breaker on the panel was ambient temp. This is Florida where temp is hot and the plug is in full sun.

Did you add the smart plug to an existing shore power cable or buy a new cable with a factory installed plug?

What are the connections like on the Smart Plug receptacle on the boat?

Don S/V ILLusion · May 22, 2023

You definitely have a resistive connection, either the male plug or in the female receptacle. As you replaced the plug/cable, it’s the receptacle into which it’s plugged. There should never be much heat generated regardless of ambient temperature.

i would talk with the marina or whomever supplies the power head to investigate. Immediately! If it happened here,it’s likely a systemic problem in other heads lacking proper maintenance and inspection.

Ralph Johnstone · May 22, 2023

Don S/V ILLusion said:
As you replaced the plug/cable, it’s the receptacle into which it’s plugged.

Precisely.

jviss · May 22, 2023

Don S/V ILLusion said:
either the male plug or in the female receptacle

This can quickly get confusing (at least for me), as the "male plug" is the thing that's installed in the boat, and the "female receptacle" is on the end of the cord, in this application. SmartPlug calls the thing installed on the boat the "inlet" and the thing on the end of the cord that you plug into it the "connector."

Ralph Johnstone · May 22, 2023

Sailm8 said:
I found charred wires so I replaced both the SmartPlug and the entire cord

Did you change the plug which is the part mounted on your boat ? The first thing to look at is the wiring on the back of the plug and see if it's corroded. You can then take a resistance reading across the plug prong and its bare wire portion to see what's going on there.

Scott T-Bird · May 22, 2023

Now, I'm curious, too. We have no idea if you are talking about the inlet on the boat, the connector at the end of the SmartPlug cable, or an SmartPlug adaptor on a conventional cord. I'm also not understanding how it might be related to the marina's power supply. (Don't confuse me with an electrician!)

jviss · May 22, 2023

Ralph Johnstone said:
the plug which is the part mounted on your boat

SmartPlug (the manufacturer) calls that part the "inlet." I believe what they would call the plug is the thing on the end of the cord, but they call that the "connector."

Davidasailor26 · May 22, 2023

From your description it sounds like this has now happened on two separate cords/plugs? If so I would suspect that there is a bad connection on the boat side of the inlet. Extra resistance there would heat up the prong, which could carry the heat into the plug, making it seem like the plug is the problem because that's the part that's exposed/touched. Either that or the prong itself is corroded leading to a bad connection of the plug.

Ralph Johnstone · May 22, 2023

jviss said:
SmartPlug (the manufacturer) calls that part the "inlet." I believe what they would call the plug is the thing on the end of the cord, but they call that the "connector."

Big Deal. Once had one of my crew yell to me in a transient marina "Hey, plug in the electric hose, will ya ?"

I just prayed I would never see any of those people staring at me so long as I live.

Benny17441 · May 23, 2023

For safety, make sure that breaker at the control panel is actually tripping properly and not allowing overloads or shorts. Breakers don't last forever and any breaker over 20 years old should be replaced. There is either a loose connection or the wiring has been damaged by repeated overheating. Unless you are familiar with electrical testing I would suggest you contact an electrician to conduct the tests on the circuits, wiring and breakers.

thinwater · May 23, 2023

It sounds like this was at the boat end. Also, he said he had just washed the boat.

The clues imply that the seal around the plug has failed and that he has not kept grease on the male part. The water/salt solution conducted power and the cord got hot. This can do serious damamge. It is also possible that the hose end fell in the water at some point in the past and was not rinsed and dried, or because salt ran in from the deck over time.

You have to keep any plug clean, salt-free and lubed, or ....

jviss · May 24, 2023

Sailm8 said:
Thank you everyone for the suggestions. I am awaiting the delivery of the male (boat side) plug and will have more info or a solution, hopefully, soon. I'll post the results.

Thanks for following up. I'm curious, what made you think it was the boat side connector that's at fault?

thinwater · May 25, 2023

jviss said:
Thanks for following up. I'm curious, what made you think it was the boat side connector that's at fault?

In the first post he said he noticed this "while washing the boat." While that could have been a coincidence, it seemed to imply he thought water had something to do with it (otherwise why mention the washing). He also mentioned a liquid good running out of one pole. It could have been melted plastic, or a water/corrosion solution, but he didn't clarify.

Ralph Johnstone · May 25, 2023

jviss said:
Thanks for following up. I'm curious, what made you think it was the boat side connector that's at fault?

He first replaced the OUTY* end of the cord but the connection remained hot and the breaker didn't blow. The breaker is a "maybe" indication that it's not an overcurrent situation. If it wasn't the OUTY* end, it had to be the INY* end at the hull.

* I can't keep these Smartplug labels straight.

jviss · May 25, 2023

Sailm8 said:
He also mentioned a liquid good running out of one pole. It could have been melted plastic, ....

He said "I unplugged it and found it goo rhad run out of one plug hole and it smelled burnt."

The "plug holes" on these are on the cord end, not the boat end.

thinwater · May 25, 2023

jviss said:
He said "I unplugged it and found it goo rhad run out of one plug hole and it smelled burnt."

The "plug holes" on these are on the cord end, not the boat end.

I thought it was clear this implied the boat end of the cord. Inexact terminology is rampant.

jviss · May 25, 2023

thinwater said:
I thought it was clear this implied the boat end of the cord. Inexact terminology is rampant.

Previously in this thread I made an attempt to clarify terminology. Maybe you missed it. But it is confusing. I figure "plug holes" means the mating part that has the receptacle, and the plug is the thing that has the blades that go into the receptacle.

Scott T-Bird · May 25, 2023

thinwater said:
In the first post he said he noticed this "while washing the boat." While that could have been a coincidence, it seemed to imply he thought water had something to do with it (otherwise why mention the washing). He also mentioned a liquid good running out of one pole. It could have been melted plastic, or a water/corrosion solution, but he didn't clarify.

I took it to mean that he was removing the connector from the inlet on the boat because he was washing the hull. I would do the same ... I wouldn't be spraying water around a live inlet and then wiping down the hull right next to it. But on the other hand, I would also first shut off the power at the dock pedestal and perhaps that is the end with the connector that would be noticed first. But I'm still supposing that after shutting the power off at the pedestal, he noticed the heat while disconnecting the inlet connector.