Let's Name the Electrical Problem...

[Paul Beyer]

Originally Posted by sparrowhawk1

Could not have said it better and it's amazing how many marinas are wired improperly

I disagree with this statement. The VAST MAJORITY of the time it is a boat issue. We mislead the general public with statements like "HOT MARINA" when in fact it is the boats causing the problems. Most well managed marinas would not have their wiring backwards.

[goboatingnow]

Originally Posted by jeepbluetj

Open neutral or reversed hot/ground. Both are dangerous. (reversed hot/ground is real dangerous)

The "hot" pin on 120v NEMA is the smaller pin, both in the NEMA-15 and the NEMA-30 twist lock. There should be no confusion what should be hot on a receptacle, it's polarized.

I don't think I have ever seen hot and ground reversed, that usually trips the breakers immediately.

hot and neutral, reversed, yes that happens from time to time, it doesn't make the boat immediately dangerous however.


dave

[jeepbluetj]

Originally Posted by goboatingnow

I don't think I have ever seen hot and ground reversed, that usually trips the breakers immediately.

hot and neutral, reversed, yes that happens from time to time, it doesn't make the boat immediately dangerous however.


dave

I agree a hot/gnd reversal would be rare, and a properly wired 110v panel would have a breaker that would trip on that. But a single pole breaker (no ground fault) won't. From the factory, my catalina would have not tripped with a hot/gnd reversal. Not knowing what the OP is dealing with breaker wise (and it may be within the boat - i.e. a miswired outlet) a hot/gnd reversal fits the symptoms.

The other possibility I mentioned is open neutral - which can be dangerous without a CGFI in the circuit (if current is bled to gnd instead of N)

[accomplice]

I would suspect a cable/connector mis-wiring issue. I suggest checking the terminal posts at the dock with a voltmeter, and then on the boat-side of the cable. It does sound as if hot/ground are swapped. As others have said, this could be dangerous.

[transmitterdan]

Originally Posted by letsgetsailing3

Old, unfamiliar boat. Tested shore power, and found a "reverse polarity", with either the "hot" or "neutral" to ground producing 120V. "Hot" to "neutral" (two pronged) produces zero volts.

Consistent finding on all boat outlets.

What does this mean, and how would I find the problem?

Does anything powered by AC on the boat run? Is so then your measurements might be in error.

If measurements are right It sounds like hot and ground are revered at the boat AC inlet. Not likely a problem on the doc side. Could be a miswired shore cable but probably not.

I would call an electrician. Once problem is fixed suggest you have the electrician test the galvanic isolator. This condition might have blown it up.