ABYC power feeder code E-8.11.4.1 vs E-8.11.9.2.1

Discussion in 'Electrical Systems' started by sdowney717, Jul 8, 2011.

  1. sdowney717
    Joined: Nov 2010
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    sdowney717 Senior Member

    http://www.cruisersforum.com/forums/f14/excerpts-from-abyc-electrical-1471.html

    I am somewhat confused on this.
    My situation is the old boat has no fuse or breaker in the AC shore power main feeder line. And the shore receptacle is more than 10 feet away from the shore-gen-off rotary selector switch. It does have polarity alarm and polarity light.

    So I plan to put in a breaker. Does this breaker need to trip both neutral and hot simultaneously or just the hot?

    10 foot rule, I understand
     
  2. Bglad
    Joined: May 2010
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    Bglad Senior Member

    All the diagrams in my ABYC book show double pole breakers on 120 volt system shore power mains. Single pole breakers are ok on the main panel for branch circuits if you have a reverse polarity indicator. If not double pole breakers are required there too for 120 systems. If you can find one install an ELCI type breaker for your shore power main. It monitors current flow on and off boat and trips if it senses leakage. Similar to the type used on hot tubs.
     
  3. sdowney717
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    sdowney717 Senior Member

    ELCI pricey about 150 per breaker. so then $300 plus some cost for a box to hold them, perhaps someday. They are GE double pole in a wet location steel load center.
    I already bought two double pole 30 amp breakers and boxes.
    I do have GFCI on the outlet circuit.

    yes I did find out quite a bit researching these things. Fresh water you are at much greater risk. Also NEC has finally written code for marina shore power and they now require ELCI on the power before it gets to the boat which is better than nothing.
    So do you think my old marina will get these new devices and what is the timeline for implementation?
    As the article mentions, ELCI trips at 30 milliamps which is higher than what is needed to kill.


    http://www.iaei.org/magazine/2010/09/ground-fault-protection-for-marinas-and-boatyards/
     
  4. Bglad
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    Bglad Senior Member

    What is your hull material?
     
  5. sdowney717
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    sdowney717 Senior Member

    wood hull, in the ocean water.
    And the entire hull has been rubberized inside and outside, coated with sanitred permaflex.
    Does that help?
     
  6. Bglad
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    Bglad Senior Member

    Just curious. If you have been reading about electrocution drowning you have probably seen that one of the causes is stray AC current traveling out of the hull via underwater metal parts. The primary cause of these fatal incidents I am aware of on boats is not having the AC green ground, DC negative and bonding system tied together. Without this connection AC faults to the DC side can rise to whatever voltage is available and transmit that current into the water hence the hazard to swimmers or divers working under boats. With a connection the AC circuit sees the fault tripping the breaker.

    I have done numerous inspections on wood and steel boats where this connection has been avoided for purposes of avoiding corrosion damage. Wood and steel boats are the usual culprits because they tend to have more hands on owners and are very concerned with corrosion (as they well should be). I take my time but am usually able to convince them the AC current is not their corrosion problem and by not tying together the DC negative and green ground they are risking theirs and others lives!
     
  7. sdowney717
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    sdowney717 Senior Member

    That connection still exists intact on my boat.;)
    the DC ground and AC ground are connected.
    What is disconnected is the bronze through hulls.
    Then engine grounds and tank grounds are intact.

    Over the last month I have been through the entire system.
    The boat is a 1970 Egg harbor 37.
    When built, they used romex solid copper wire for all the wires coming from the breaker box, no GFCI at all.
    The supply lines are coarse multi stranded.

    I replaced all the wires from breaker box with fine strand 12 gauge wire.
    I used a 100 foot heavy duty 12 gauge extension cord. So the wires are not marine tinned. The cable jacket is very heavy thick, not like your regular extension cord.
    Pulling out and looking at 40 year old wire, it was all in very good condition, none was marine tinned wire, even the multistranded wire was in good shape. The romex had not failed. I ran some conduit in various places to help keep the new wires from rubbing and it is well supported, nothing left to swing around.
    I soldered all the ends and hooked the wire up to tamper proof outlets.
    (I know soldering well and I did not want any possible corrosion to develop where the wire ends meet the outlet screws.)
    All the outlets are loaded from a 20 amp GFCI outlet located in a new hole by the chart table. I deliberately put the fridge on non GFCI. I like the back wire outlets. They are a little easier to hook up. Plus with their 8 back wired large holes, you can bring 3 cables into the box and hook it up without using wire nuts.

    I have seen multistrand wire totally disintegrate. This boat has a cabin so the wire must stay dry and no salt water gets to it so the wire stayed good all those years.

    I would have preferred to use a 30 amp GFCI in the GE box as a main breaker for the entire boat, but the ABYC talks of breaking both neutral and hot simultaneously. I can understand perhaps that issue if the neutral is actually hot, but their is a reverse polarity light and alarm so it would show up immediately. Boat has twin 30 amp power. So I ended up using 2 30 amp double pole breakers in a wet location GE outdoor box for the 10 foot disconnect rule. Boat had never had an issue without those breakers.
    I choose the GE Power Mark Gold Load Centers since they use copper buses. I left the existing main lug Square-D breaker box where it was.
     
  8. Mark Cat
    Joined: Jun 2011
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    Mark Cat Senior Member

    sdowney717,

    There are several reasons to have the two pole breaker on 30A, 125VAC single phase. The most recent is the use of an ELCI for AC leakage detection.

    The two pole breaker isolates (when off) the boat from shore power until proper voltage and polarity can verified. Obviously, to work shore power voltage and polarity sense has to be on the shore power side of the breaker. This procedure is part of the shore power connection sequence from ABYC.

    So, if shore power was improper, you would go to another slip or choose not to connect. The voltage and polarity indicators are an aid to verify proper shore power. The indicators are used as part of a procedure.

    Also, from an NEC standpoint for AC, although not specifically targeted at boats, requires a main UL489 disconnect before the main breaker panel board. Due to the low AIR, UL1077 breakers can be used in Marine Pleasure boat shore power. From this standpoint, servicing of the main panel board requires a main disconnect. So for electrical work the technician can LOTO the main breaker while work is done if the main is out of direct line of sight from the panel. AC Marine designs should include consideration of service and repair of electrical systems for personnel safety. For AC I use NFPA 70E procedures.

    Marine breakers also have different UL ratings, for mold, materials, and others, for use in marine salt water environments, above and beyond the land based UL "wet" location. For NEC Marina shore power installation see NEC 2011 Article 555.

    In my designs the Marine panel board copper bus bars are all tinned. So there is really no exposed bare copper.

    Extension cord is considered "flexible cords" from UL and is never part of a permanent AC branch circuit installation. ABYC essentially does the same by limiting the type of wire used for AC branch circuits.

    Mark
     

  9. sdowney717
    Joined: Nov 2010
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    sdowney717 Senior Member

    same with the GE power mark gold load centers and the QO load centers. Copper buses with tin silver colored exteriors.

    Back in the day, boats were considered 'appliances' , sort of like an extension cord with the main breaker on the pier or land.

    These new disconnect breakers are about 5 feet away from the main lug load center.
    Line of sight, yes, they are on the same side of the boat sitting behind wooden doors. So not like far apart in different areas of the boat.
    There is also a shore-off-gen switch to disconnect everything right there close to all of this.

    ok, now for a little fun thinking,

    How about if I used 2 single pole 30 amp GFCI GE breakers on the hot wire with handle ties joining to standard 30 amp breakers on the neutral wire?

    like these here
    http://www.galesburgelectric.com/GE-THT104-Solid-Snap-on-Trip-Indicating-Handle-Tie.html

    handle ties turn off both breakers simultaneously manually, but breakers still electrically trip separately.

    Or

    I was thinking I could add another box with GFCI 30 amp breakers for ground fault protection, right next to the new double pole breaker box. 5-6MA tripping instead of 30 MA ELCI for the whole boat.
    So it would be shore cords to receptacles to double pole 30 amp breakers box to two 30 amp single pole GFCI breakers to gen-off-shore switch to load center. The GFCI would be for my benefit and the double pole simultaneous trip for ABYC code benefit.
    this is still a lot cheaper than buying 2 30MA ELCI breakers and some king of panel box.

    if the electric system was in good shape, what kind of nuisance tripping would happen with GFCI on the entire boat at 5-6 MA leakage. Assuming only a fridge and microwave are using outlets continually plugged in, and a princess 3 burner stove-oven, a cruise air heat pump, 2 electric heaters being hardwired? And the wires are not exposed to water, everything forward of GFCI is dry.

    I sort of dont like a 30 MA ELCI trip current as it still has power to kill, 20 MA is all that takes.
     
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