Circuit breaker question

The main circuit breaker on my 120 volt panel is toast I believe.
I have an older Taiwan trawler, 120 V 30 amp going to the boat. The main breaker is a double breaker, 2 singles riveted together with a single switch poking thru the panel.
My question is do I need a double or can I use a single breaker of 30 amps?

Current breaker trips randomly after being on for a while so I am thinking the contacts are shot. It is an Airpax and I am just starting to do a search for one. What I can read on the label says 220 V 50/60 Hz, 60 amps and I can't read the delay time.

Thanks in advance.
Jay

Single breaker = 110V
Double breaker = 220V (110*2)

You have 2 wires coming into the panel, you need a breaker for each leg, hence the double breaker. Half of your double breaker might be getting weak - they are mechanical and they do wear.

You might also be overloading one leg - you need to make sure your load is balanced across both 110v legs

On a marine shore line you are required to interrupt the neutral as well as the hot. You must go back with the double breaker.

Thanks for the replies. I see why there are two legs now.
Yes I believe only one leg is weak. When it trips, I still get a reading on the panel meter (top breaker) yet there is no power to the circuits (bottom breaker).

IT is good practice to use a double breaker on the first on board breaker after the power inlet..Black and White wires break , never Green Ground wire.

This will protect the boat even IF the polarity is reversed coming on board .

I have seen 2 single breakers used and a tie bar...not sure if that's the best way...but it does work and I believe I have read that it meets the rule of breaking hot/neutral satisfactorily.

psneeld said:

I have seen 2 single breakers used and a tie bar...not sure if that's the best way...but it does work and I believe I have read that it meets the rule of breaking hot/neutral satisfactorily.

Click to expand...

What I have found so far all have tie bars. Mine only has a switch on the top breaker. I'll have to cobble up the panel to fit a tie bar breaker. I can doi that but it's not my first choice.
Luckily I have all winter to find an exact replacement.

Maybe I'll take mine apart and see what makes it tick. I worked at GE for a short while supporting a circuit breaker manufacturing plant so I'm dying to cut it open.

something like this possible?

PANELTRONICS BREAKER 30 AMPS W/ REVERSE POLARITY TRIP COIL [29878] - $37.29 : SaltysMarine.com

this may be it

http://www.paneltronics.com/PartsCo...oryAll&partscomponents=&product=&perpage=3000

The ABYC also recommends a double throw breaker between the shore power plug and the main select switch to protect the switch whish is the cause of many electrical fires. Double pole is advised incase the polarity is switch so the break will still be thrown. We had an insruace survey and the electrric was the first and primary he looked at.

psneeld said:

something like this possible?

PANELTRONICS BREAKER 30 AMPS W/ REVERSE POLARITY TRIP COIL [29878] - $37.29 : SaltysMarine.com

this may be it

Circuit Breakers

Click to expand...

If the breaker truly is one of these types, the reversed polarity trip coil will add another thing to check.

Someone please keep correcting me if I'm wrong on this. (my newbie boating electrical knowledge was evident in my last post)

The only thing available with to reference for reversed polarity with AC current would be checking voltage across a shunt between the neutral and ground legs. According to the specs, if there is more than 65vac potential across the neutral (white) and ground (green) legs, the breaker will trip.

theran5317 said:

If the breaker truly is one of these types, the reversed polarity trip coil will add another thing to check.

Someone please keep correcting me if I'm wrong on this. (my newbie boating electrical knowledge was evident in my last post)

The only thing available with to reference for reversed polarity with AC current would be checking voltage across a shunt between the neutral and ground legs. According to the specs, if there is more than 65vac potential across the neutral (white) and ground (green) legs, the breaker will trip.

Click to expand...

If you have reverse polarity (in it's simplest form) the neutral has been wired for hot and a voltmeter from neutral to ground will just show 110 or whatever the dock is carrying....

Many reverse polarity lights are nothing more than a 120V light wired directly between the neutral leg and ground bus bar.

psneeld said:

this may be it

Circuit Breakers

Click to expand...

I think this is exactly what I need. THANKS

As a follow up....
I received the Paneltronics breaker that Scott suggested. Fit well but I had to file the sides of the hole with a small square file because the switch needed room to swing.
Other than that looks fine.
I'll know sometime next summer if this was the problem.

I did take the old breaker apart and the contact was down to a single point and looked a little arced. Hopefully that was the issue, causing it to heat up and open.

Circuit breakers do wear out. There are a few different types. I'm guessing the marine panel you got is from the family that that has switch like durability.

Gotta keep the mains a twin breaker. Reversed polarity AC is indistinguishable in operation (polarized refers to the plug, not the electricity), but is a shock hazard when a corroded internal wire falls onto the metal case of a two prong appliance. Scenario: a toaster gets plugged in and does not work because of corroded wires. User has revered polarity shore power and a single 30 A panel board (wired like a house). User shakes appliance and gets electrocuted.