Shore Power - Harbor Mate Install

[Hammer]

I have a new dock on the canal behind my house. Builder ran two 30 AMP, three wire (red, black, white) circuits to post. I am using one for shore power. The other I am saving in case i ever want to install a lift. One green ground wire back to house panel. Using Cantex PVC junction box and underground conduit. Eaton Newport Harbor mate for the sub panel and outlets.

As shown in the Eaton installation instructions, on the bus I have black wire on line one, white on neutral, red on line 2. Green on green.

The harbor mate has a prewired loop on the black wire outlet lug for a 20 amp non shore power socket. Also a loop on the red post for a led lamp. The harbor mate has separate breakers for each outlet, 30 30 + 20.

At the junction box, I have wire nuts for black to black, white to white, red to red, green to green. No separate ground to earth.

Every time on turn the circuit on at the house, it pops off. To trouble shoot, I disconnected the black to black wire in the junction box, so only the red line 2 is hot at the bus. The red wire circuit works and their is power to the bus and one 30 amp outlets.

The disconnected black wire in the junction box is hot. If I wirenut the black to black again in the junction box, the circuit pops.

I have no clue what is going on? Any ideas?

 

[SteveK]

At the house, is it a GFI breaker? Is it a two pole 30 amp breaker and both pop. sorry, not enough info and the picture does not explain why you have 3 ground wires, 3 black but only 2 white, 2 red

 

[O C Diver]

While I'm not familiar with the Harbor Mate, is the house breaker GFI, the Harbor Mate breaker GFI, and the duplex outlet GFI? You may be developing a ground problem with too many GFIs which trips the house breaker.

Ted

 

[Porgy]

This sounds very familiar. Two hots sharing a single neutral creates an imbalance that a GFI or ELCI reads as a fault. That’s all I got but I think has been discussed here before.

 

[Hammer]

No cfi at house panel.

 

[Hammer]

Only the 20 amp gfi on the harbor mate. None in the house panel.

 

[Hammer]

There are only two black and two red. They are used as a loop. Red to a light. Black to the 20 amp. But it should be noted I don’t have the harbor mate breakers open.

 

[O C Diver]

Is the duplex (house style receptacle) a GFI?

Ted

 

[twistedtree]

In the junction box, if you measure between red and black, what do you get? I'm wondering if red and black are on the same leg rather than opposing legs.

 

[SteveK]

In the junction box, if you measure between red and black, what do you get? I'm wondering if red and black are on the same leg rather than opposing legs.

I think you are on to it. The two red are both on either L1 or L2, but the two black are one to L1 and one to L2. tie them together and breaker pops.
put a meter between the two separated black and it may be 230V whereas the two red separated would not have any voltage between them.

 

[Hammer]

Update: The solution was we found a corroded wire at the junction box on the outside of the house. This was the junction box before the PVC entered the ground. We discovered any load put on the circuit with the corroded wires threw the GFI in the house panel. The wires were corroded because the house builder used a metal box outside instead of plastic. No gaskets on the threaded top plugs. No sealer in the PVC pipe lead into the box (Florida ground PVC is famous for holding water from condensation) and no drain hole in the metal junction box. We replaced the junction box with cantex, cleaned all the wires and used new connectors. We also replaced 20 amp GFI plug at the dock subpanel because the house panel breaker was GFI. We didn't want problems caused by two GFI on the same cirucit.