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Discussion Starter · #21 ·
I think that if my main breaker panel more than 10 feet of wire from the shore power inlet, I'll include a double pole breaker near the inlet and use a single pole breaker on the panel. If not I'll probably just go with a double pole breaker at the panel.

This has been very helpful, thanks to everyone.
 

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I used to sit on the ABYC Electrical Systems Committee from the late 80's until 2004 . I am also a retired Coast Guard engineer that worked with boat manufacturers to help them comply with Federal Regulations for recreational boats. First, there have been many studies done concerning fires on boats and by far most of them are electrical in nature. The rule for distances (in this case ten feet) is simple. The breakers are there to protect the wire. When there is too much current on the line wires melt and start fires. The ABYC standard E-11 electrical systems is designed to prevent this by requiring the breakers be as close to the source of power as possible. The outlet on the dock is not the source of power on the boat, and it has it's own breaker. The breaker panel on the boat is. As some one mention each branch off that has to be protected. On small boats it is fairly easy to put the breaker (or fuse) within a few inches (7 in the regs) or up to 40" if it's in a sheath such as wire loom, but on bigger boats this gets difficult. So the committee, made up of industry people, surveyors, electrical engineers and plain old boatbuilders and other interested people (Nigel Calder used to be on the Electrical PTC, don't know if he still is) has to decide what is a safe distance. I don't recall the discussion on that specific (I retired in Oct 2004) but I'm sure it was a heated discussion (they usually are). Anyway here's the text

11.10.2.8.3
Additional Overcurrent Protection -
If the location of the main shore power disconnect circuit breaker is in excess of 10 ft (three meters) from the shore power inlet or the electrical attachment point of a permanently installed shore power cord, additional fuses or circuit breakers shall be provided within 10 ft (three meters) of the inlet or
attachment point to the electrical system of the boat. Measurement is made along the conductors.
11.10.2.8.3.1
If fuses are used in addition to the main shore power disconnect circuit breaker, their rating shall be such
that the circuit breakers trip before the fuses open the circuit, in the event of overload. The ampere rating of the additional fuses or circuit breaker shall not be greater than 125% of the rating of the main shore power disconnect circuit breaker. For 120 volt service, both the grounded and ungrounded current
-carrying conductors shall be provided with this additional overcurrent protection. (My note: this means double pole breakers)

11.10.2.8.4
If required, overcurrent protection for power -feeder conductors from AC generators and inverters shall be
within seven inches (178mm) of the output connections or may be within 40 inches (102 cm) of the output connections if the unprotected insulated conductors are contained throughout their entire distance in a sheath or enclosure such as a conduit, junction box, or enclosed panel
 

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Discussion Starter · #23 ·
Sorry to wake this thread up, but as I plan my installation, I'm trying to balance safety, requirements and aesthetics. I have limited space for an AC panel, and I'm trying to get four circuits. My shore power inlet will be more than 10 feet of cable away from the panel so I'll add a double pole breaker as close to the shore power inlet as practical (but within 10 feet). At this point, does my panel need either a single or double pole branch breaker, or can I simply have a panel with four circuits?
 

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Breakers are there to protect the wires after the breaker. if the wire is big enough then you do not need another breaker. Anyime the wire gets smaller you need a breaker or fuse before the size change
 

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Breakers are there to protect the wires after the breaker. if the wire is big enough then you do not need another breaker. Anyime the wire gets smaller you need a breaker or fuse before the size change
If the OP wishes to be ABYC compliant he does need another breaker if the panel is 10' or more cable length between inlet and panel.
 

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Sorry to wake this thread up, but as I plan my installation, I'm trying to balance safety, requirements and aesthetics. I have limited space for an AC panel, and I'm trying to get four circuits. My shore power inlet will be more than 10 feet of cable away from the panel so I'll add a double pole breaker as close to the shore power inlet as practical (but within 10 feet). At this point, does my panel need either a single or double pole branch breaker, or can I simply have a panel with four circuits?
If ABYC compliance is your aim, you should have a double pole breaker OR a single pole breaker and a polarity indicator on the panel.
 
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