Main breaker tripping

[Lruel]

Hi, I just bought a Mariner 420 2004. The shore power cable is a 50amp 125v/250v cable. When I took possession of the boat it came with a 30amp 125v to 50amp 125.250v pigtail. With this cable everything on the boat is working fine. I can power shore 1 and shore 2 with it. Although we are tight on power when the 3 air conditioning systems are on and drawing power.

I bought a Reverse Y cable 2x30amp (shore side) to 1x50amp (boat side) - model marineco RY504-2-30. When I use this cable the main breaker on the boat trips immediately.

Any idea on why this would happen?

Thanks in advance for your help

Laurent

[Viper]

Welcome aboard.

I wonder if you have reverse polarity on one of the shore power outlets. Take an additional 30 amp cord and try plugging one of the legs into a different pedestal to see if that solves the problem. If it doesn't, try the same with the other leg. If this doesn't solve the problem, ask another member in the marina with the same reverse Y cable if you could borrow theirs to test or try your cable on their boat. It could be that you bought a faulty unit.

When the breaker trips, does it allow you to reset? If you reset, does it trip again right away or does it stay on? Some setups will trip the mains when power is applied after it's been disconnected but will operate normally once the breaker is reset.

[Lruel]

Hi thanks for the reply Viper,

I did try other outlets and it does the same thing.

The breaker continues to trip even after reset.

If there is no load on the main, the breaker doesn’t trip. But, even if all the breakers are off, when I put the shore 1 breaker on, it trips the main.

The shore 1 breaker was just replaced and I just. Saw on the invoice they replaced it with a 75amp one. Wonder if that could be it since the main is a 50 amp???

[tomschauer]

If I'm not mistaken, your 120/250 uses a common neutral wire. Your reverse splitter most likely has two neutral wires. So one of your mains doesn't have a neutral and is tripping the breaker.
Maybe call Marinco, and ask what is the proper splitter to use?

[tomschauer]

Oh, I would also get that 75 amp breaker replaced with the proper 50amp.
Being oversized won't cause it to trip, but it does not protect your wiring from overloading and possible burning of wires, etc. This is a major hazard.
There is also a chance they used the wrong type breaker, or installed it improperly. That could also be causing your problems.

[Midnightsun]

What do you have for inlets on your boat? Single or dual?

[Lruel]

Found the issue.

I asked one of my neighbour to try his Reverse Y cable and everthing works fine with his cable.

Viper you were right in your 1st reply, my brand new MARINECO RY504-2-30 cable is a faulty cable out of the box. Can't beleive they don't test their cables before shipping them

Thanks all for your replies, really appreciated.

Laurent

[Viper]

Glad you found the problem. You need to replace that 75 amp breaker as Tom mentioned. I suspect it was a temporary fix, likely the only one on hand when the original failed and was never corrected. It's a matter of time before everything is just right for a catastrophic failure.

[Lruel]

Yes, wll have that replaced asap

Thanks again!