Overloaded 120v circut blew circut breaker

[hardshell46]

Hi all,

i have a heater running in the engine room and a small space heater in the hall and went to plug in a vacuum and blew the breaker. The problem is that none of the panel
circuit switches have tripped. What am i missing here? I'm in the dark.

Tom

 

[SeaEric]

Does your boat have the screw in fuses near the shore power cord inlet? Look there.

 

[brian4190]

check all your outlets for gfci. one of them may have tripped.

 

[Canuck Dennis]

If you have enough load spread across breakers the shore power breaker will go but not the individual ones, been there and do that.

 

[hardshell46]

Does your boat have the screw in fuses near the shore power cord inlet? Look there.

thanks for responding, she does and I will look there

 

[MikeP]

If you have other circuits still working, you still have shore power on the boat so unless you have multiple SP input cables, it seems likely that either you have missed sighting the correct breaker for that circuit OR, as noted, a GFI has tripped.

 

[hardshell46]

Does your boat have the screw in fuses near the shore power cord inlet? Look there.

the problem as it turned out was a 50amp fuse in the the cock pit at the ships service, thanks for all your help.

Tom

 

[hardshell46]

If you have other circuits still working, you still have shore power on the boat so unless you have multiple SP input cables, it seems likely that either you have missed sighting the correct breaker for that circuit OR, as noted, a GFI has tripped.

Mike, it turned out to be a 50amp fuse at the ship service in the cock pit, thanx

 

[SeaEric]

the problem as it turned out was a 50amp fuse in the the cock pit at the ships service, thanks for all your help.

Tom

It was a lucky guess. Glad I could help.

 

[MikeP]

Glad you found it though I don't understand something… did you lose shore power to all your circuits? Do you use multiple shore power cables? With one cable plugged in and you blow that 50A master fuse, there should be no shore power anywhere on the boat. I'm conFUSEd!

 

[bobk]

Glad you found it though I don't understand something… did you lose shore power to all your circuits? Do you use multiple shore power cables? With one cable plugged in and you blow that 50A master fuse, there should be no shore power anywhere on the boat. I'm conFUSEd!

There re two fuses on a 50A 240 V line. One leg remained hot?

Bob

 

[MikeP]

Well…that makes sense but if I lose one 50A shore power fuse on our '80 53MY, there is no shore power at all available in the boat. It suddenly occurs to me that it could be the difference between having isolation transformers and not. I don't know how the transformers are actually connected, never having looked at that at all, but it is my understanding that with iso transformers the shore power ground is not brought aboard. If that is the case, then it seems to me that both sides of the 240 (120VAC each) have to be present for the transformer to provide any output.

But my understanding of that could be wrong…

To the OP, does your boat have isolation transformers?

 

[holtcl]

I must have read this wrong from the first post, because I thought he tripped an individual breaker on the panel, not the 50 amp service. On rare occasion (like maybe it happened once), I'll trip one of the single breakers on the panel but the switch won't actually flip over. Anyone had that happen? I thought that was what was going on here when I read the post but I guess not if he's talking about the 50 amp.

Cheryl
Cinderella
1971 53 MY

 

[MikeP]

You may be right; I assumed he was talking about the main shore power input(s). I may have misread/misunderstood. Not sure how that could possibly happen!

 

[hardshell46]

Mike, I never lost shore power. I have 1 50amp line from shore split to 2 30's, 1 side is for the a/c,

replaced that 50amp fuse ( $3.39 2 pack at home depot, Sam's wanted 19. + ship) and all is well, hope this helps.

Tom

 

[saltshaker]

Mike, I never lost shore power. I have 1 50amp line from shore split to 2 30's, 1 side is for the a/c,

replaced that 50amp fuse ( $3.39 2 pack at home depot, Sam's wanted 19. + ship) and all is well, hope this helps.

Tom

If that's your set up then someone modified it. Sounds like you have 30A inlets supplying 50A service. You should have 2 50A 125V inlets, one for shore power and one AC. If you are using a 30A cord and blew a 50A fuse, you are overloading the cord. Common practice and also a common source for a fire. If that's what you have, you should replace the inlets with one 50A/250V receptacle. That will give you the intended 50A 125V to each service panel. Very simple upgrade on your boat.

 

[bobk]

Slightly off topic, but I recently lost ships power but still had power to the 50 amp plug. It turned out there was some corrosion on either the fuses or the contacting surfaces. A bit of cleaning and all was well (after the inverter bank went flat). This has happened twice, so now I keep the invert function off when not in use.

Bobk

 

[MikeP]

Concur re inverter - when the boat is unattended, I ensure the inverter is "off."