Shore power/electrical question

[chrispuryear]

I have a 37C. Stayed on the hook all weekend using the generator. All was well. Came back to dock, hooked back up to pedestal, turned on the salon a/c and it would not turn on and was making a weird sound. A couple of outlet breakers tripped in house also. I immediately shut off the 2 breakers on the panel. I looked at the volt meter on the panel and it was pegged. So I guess the shore power was feeding 240 v through the system. I was plugged in using a 50 amp line split to 2 30amp receptacles on the boat as I always do. Went to another pedestal and everything went back to normal with the exception of an electrical smell at panel and one of breakers for the inside receptacles trips after a minute or 2. Any ideas would be helpful.

Thank you,
Chris Puryear

 

[MadHatter53]

Test everything. The post, the cord, the splitter. If everything tests good then with all breakers and shore power switch off, test back of inlet then to switch then main breaker. You probly fried something behind the panel with the power spike. Sound like it's something at the post or feeding it, could even be that your splitter didn't split. Be sure to look behind the panel after it's fixed and replace anything that doesn't look good.

 

[SKYCHENEY]

Sounds like the neutral was energized. Not good. Could be the pedestal or the splitter.

 

[Cricket]

Where you using a "smart" splitter or just a regualr no frills "Y" splitter?

 

[SKYCHENEY]

Where you using a "smart" splitter or just a regualr no frills "Y" splitter?

I think he said it was split from a 50a 240v to 2 30amp 120v going into the boat.

 

[Cricket]

I think he said it was split from a 50a 240v to 2 30amp 120v going into the boat.

Yes, Chris Puryear posted "plugged in using a 50 amp line split to 2 30amp receptacles on the boat".
Please tell me where the post states the actual type of splitter used?
The term "splitter" is generic in my opinion, which is why I was looking for clarification.

It seems that dock wiring is very suspect just about everywhere, we've even had issues at some of the finest marinas where you expect perfection.
The lesson to be learned for the HOF community, and what's really important, is that non-smart splitters are dangerous.
This might be a very good example of what can happen if a non-smart splitter was used.
Luckily nobody was electrocuted and the boat didn't catch on fire.

Also, everyone should install an isolation transformer if you don't have one already, safety for all.

 

[Pascal]

Please correct me if I m wrong but when splitting a 120/240-50 down to two 120/30, the splitter is always a dumb splitter. There is no need for protection

It s when connecting a 120/240-50 cord to twin 120-30, or a 120/240-100 cord to twin 120-240-50, that you need a smart Y (not a splitter) to make sure the hots are on opposing phases

Whenever connecting at a new pedestal, it s always a good idea to turn off all the breakers first, then turn on the rotaries and check voltage on the meters before activating breakers

As others have mentioned, carefully inspect the wiring behind the panel as well as behind the shore power inlets.

 

[Cricket]

Pascal, yep you're correct, no smart splitters going the other way, single 250v 50amp male to 2 x 125v 30amp females.

 

[Dazed338]

1st guess is best guess if everything is back to normal, I'm assuming all 110 Volt stuff is still functional. The one breaker that pops probably took the biggest hit and got cooked, if that's the case got real lucky.

 

[SKYCHENEY]

Also, everyone should install an isolation transformer if you don't have one already, safety for all.

I agree. It should be a requirement.

 

[chrispuryear]

Thank you guys for all of your replies. I am not aware what a "smart" splitter is. I am not very familiar with using splitters. All of my previous boats only had one connection. I have been using a 50 amp. cord plugged into a y splitter to (2) 30 amp connections at my boat. 1 for the 2a/c units, and 1 for the house power. When I switched to another pedestal, everything worked. Curious if this could happen again while I am away from boat? Our marina got hit pretty hard by Hurricane Florence. Still not sure what happened to send the high voltage to the boat. I will always check my panel from now on before energizing he breakers. Just very uneasy to leave the boat plugged in, or staying on the boat while plugged in at the marina. Is there any way to assure, protect the circuit?

Thanks again,
Chris

 

[Pascal]

It has to be a wiring issue between the pedestal and a transformer on the dock. Something shorted on there and sent 240v on one leg instead of 120v. Did your talk to the marina?

 

[chrispuryear]

I did Paschal, and he stated that there has not been a problem. Very small marina. Only he and I at this time using shore power. I think I will not use that pedestal again.

 

[Pascal]

Did you check voltage at the pedestal? Either H/N should show 120 and H / H should show 240. If you get 240 between H and N then that’s your problem

 

[SKYCHENEY]

Again, it sounds like there is a hot neutral there.

 

[dar636]

How are isolation transformers installed on boats such as ours with multiple shore power inlet sources?

Our 58 YF can bring power onboard from 6 receptacles; (2) 50A 125/250V and/or (4) 50A 125V.

 

[Photolomy]

I would think you would get two isolation transformers, one for each 240v-50 amp circuit. The 4x 120v circuits feed the legs of the 240v circuits, if I am not mistaken.