shore power wiring/test question

[rickr104]

Hello - I have a Smartplug shore power cable on my C320. It has some diagnostics in the boat side connector to detect power-on, reverse hot/neutral, and apparently reversed neutral/ground issues. A few days ago, I had a red/blue light combo that is supposed to indicate reversed neutral/ground. Called the marina, and of course when they came to check it out, all was normal, including NO red light on my Smartplug.
My question: Is the Smartplug reliable in testing for that situation? It seems like a difficult issue to detect, with neutral and ground tied together at the panel. Anybody have experience with this? Any electricians out there?

 

[Stu Jackson]

It seems like a difficult issue to detect, with neutral and ground tied together at the panel.

What panel are you referring to?

 

[JamesG161]

Was there a lightning ground strike nearby?

Ours was burnt out recently.

Jim...

 

[Davidasailor26]

Do you have a picture of the diagnostic lights? The only Smart Plug related lights I can see on the marine part of their website is this one, which doesn’t seem to have a ground/neutral swap capability.

 

[walt]

I will take a guess. Here is the smart plug red and blue definitions https://smartplug.com/wp-content/up...rse-Polarity-Indicator-Sell-Sheet_7_28_21.pdf

This function could easily be implemented by

the blue LED detects 110 VAC between Hot and Neutral

The red LED detects 110 VAC between Neutral and ground.

First thing is that the OP said that both R and B LED on at the same time indicates Neutral and ground swapped but according to the link, this is not the case. Both Red and Blue on indicates L1 and Neutral are swapped (below is from the link)

Blue ON Red ON: L1 and neutral are swapped in a reverse polarity condition

Blue LED light on is normal, you have 110 between Line and Neutral.

But why the red temporary LED light? Remember that the ground should not be carrying any current. If something on the distrubtion had a large current draw that caused the Neutral to change voltage some because of resistive loss in the wire, this could have caused enough voltage between Nuetral and ground to light the RED led. We dont know how much voltage is required to light the LED, maybe its not that much.

Someone mentioned connected at the panel, that would be the main breaker panel which is the only place where Neutral and ground are connected.

 

[Jan_H]

The only place neutral and ground should be connected on board is in an inverter.... certainly not in the main breaker panel.

 

[High Current]

The only place neutral and ground should be connected on board is in an inverter.... certainly not in the main breaker panel.

I think he means the marina’s main breaker panel…? Because they should be connected there.

 

[marcham]

Hello - I have a Smartplug shore power cable on my C320. It has some diagnostics in the boat side connector to detect power-on, reverse hot/neutral, and apparently reversed neutral/ground issues. A few days ago, I had a red/blue light combo that is supposed to indicate reversed neutral/ground. Called the marina, and of course when they came to check it out, all was normal, including NO red light on my Smartplug.
My question: Is the Smartplug reliable in testing for that situation? It seems like a difficult issue to detect, with neutral and ground tied together at the panel. Anybody have experience with this? Any electricians out there?

Was anything different INSIDE your boat, between the time you noticed the fault and the time the marina manager came to take a look? Like water heater or another AC system plugged in or enabled? Not the same AC breakers switched ON? ....