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Old 04-14-2012, 04:51 PM   #101
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What you are describing is what I envisioned...a blue seas blade 12 or 6 position fuse panel in the fwd stateroom/head/galley, one in the main salon, one in the engine room for auto bilge pumps and other non-switched items, one aft for the master strm/head, one for lower helm/electronics and one on the flying bridge. One main running fwd to supply 4 subs, one aft to supply 2. Each fused at a main Positve post/block.

But you do give me the idea to think each sub feed from the main via a CB.
One of the advantages of the main panel-sub panel design is overlapping levels of overcurrent protection, and limiting the areas of an outage due to an equipment failure.

Here's an example...

Lets say that you have a main-sub panel topology in your electrical system. Lets say that you have a 50 amp breaker, feeding 6 awg wire going to a sub panel. At the sub panel you have distribution breakers feeding loads. wire sizes ranging from 10-12 awg and breakers of 15-30 amps.

You have a fault that results in a fail to operate of a distribution breaker (yes, this happens). The breaker feeding the sub panel will operate, protecting the system from a complete outage and possibly from a fire.

In a ring system, assuming the same fault, best case scenario is that you generate enough fault current to take down the entire ring, (but remember that your ring system is powering everything so its probably using something like 2/0 cable and a 200 amp breaker), this takes down everything. Worst case and in all probability you do not have enough fault current to take down the ring. In this case the ring powers the fault current and a fire results.

We haven't even started into the ease of maintaining, ease of fault isolation issues yet.

There are reasons why electrical systems are designed in a star topology, and where they are designed in a ring, they employ very sophisticated protective relay equipment to protect them.
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Old 04-14-2012, 04:59 PM   #102
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One of the advantages of the main panel-sub panel design is overlapping levels of overcurrent protection, and limiting the areas of an outage due to an equipment failure.

Here's an example...

Lets say that you have a main-sub panel topology in your electrical system. Lets say that you have a 50 amp breaker, feeding 6 awg wire going to a sub panel. At the sub panel you have distribution breakers feeding loads

You have a fault that results in a fail to operate of a distribution breaker (Yes, this happens). The breaker feeding the sub panel will operate. protecting the system from a complete outage and possibly from a fire.

In a ring system, best case scenario is that you generate enough fault current to take down the entire ring. this takes down everything. worsst case you do not have enough fault current to take down the ring. In this case the ring powers the fault current and a fire results.

We haven't even started into the ease of maintaining, ease of fault isolation issues yet.

There are reasons why electrical systems are designed in a star topology, and where they are designed in a ring, they employ very sophisticated protective relay equipment to protect them.
Good points....I may do just that... but I will say that I'm leary of CBs...they work for a dead short...most of the time.. but their failure rate in high amperage situations that aren't dead shorts resulting in hot wires/fires is just to high for my liking. So I'm not sure what I'll do.

Plus, I'm not sure of your example where a fault between a fixture and the sub-panel wouldn't trip a breaker/fuse and who care about the ring circuit unless it dead shorts?
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Old 04-14-2012, 06:12 PM   #103
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Good points....I may do just that... but I will say that I'm leary of CBs...they work for a dead short...most of the time.. but their failure rate in high amperage situations that aren't dead shorts resulting in hot wires/fires is just to high for my liking. So I'm not sure what I'll do.

Plus, I'm not sure of your example where a fault between a fixture and the sub-panel wouldn't trip a breaker/fuse and who care about the ring circuit unless it dead shorts?
OK, lets take your post and take an example from it.


Assume a 12 volt DC system, 12 awg wire, 20 amp breaker feeding a load.

Create a short at the equipment. For calculations assume that the short including the resistance of the 12 awg wire is .1 ohm. Assume for calculations that the panel feeding the wire has zero resistance (we call this an infinite buss in fault current studies).

Your calculated fault current will be 120 amps.

The 20 amp breaker has approx 6 times its overcurrent rating flowing through it. I do not have the time overcurrent curves for the breaker right here but a typical operate time would be in the range of say 10 miliseconds or so.

But in this case the 20 amp breaker fails to operate. It malfunctions.

Now assume that your panel with the 20 amp breaker is a sub panel off of a main panel, fed by a 50 amp breaker.

assuming no other load on the sub panel, the current through 50 amp breaker is still 120 amps. This is 2.4X the capacity of the 50 amp breaker. a typical time overcurrent curve would cause the 50 amp breaker operate in around 3 seconds.

Now take the ring system 2/0 cable, 200 amp breaker feeding the ring. its easy to see that the 200 amp breaker would never operate. I promise you thast 120 amps flowing through a 12 awg wire will quickly get hot enough to start a fire.

This concept of overlapping overcurrent protection is a industry standard in electrical equipment design for good reason.

The only way a ring system makes any electrical sense is if every tap off of the ring is to a sub panel, with the very first thing being an intermediate overcurrent protection device. Anything other than that is risking an uncontrolled overcurrent and all the hazards that come with it.

If you think about it, you have the same hazards by having a gigantic main panel on a boat, and having every load tied directly to it. A better design would be to logically divide the load on the main panel into mini sub panels for example.
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Old 04-14-2012, 06:21 PM   #104
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OK, lets take your post and take an example from it.


Assume a 12 volt DC system, 12 awg wire, 20 amp breaker feeding a load.

Create a short at the equipment. For calculations assume that the short including the resistance of the 12 awg wire is .1 ohm. Assume for calculations that the panel feeding the wire has zero resistance (we call this an infinite buss in fault current studies).

Your calculated fault current will be 120 amps.

The 20 amp breaker has approx 6 times its overcurrent rating flowing through it. I do not have the time overcurrent curves for the breaker right here but a typical operate time would be in the range of say 10 miliseconds or so.

But in this case the 20 amp breaker fails to operate. It malfunctions.

Now assume that your panel with the 20 amp breaker is a sub panel off of a main panel, fed by a 50 amp breaker.

assuming no other load on the sub panel, the current through 50 amp breaker is still 120 amps. This is 2.4X the capacity of the 50 amp breaker. a typical time overcurrent curve would cause the 50 amp breaker operate in around 3 seconds.

Now take the ring system 2/0 cable, 200 amp breaker feeding the ring. its easy to see that the 200 amp breaker would never operate. I promise you thast 120 amps flowing through a 12 awg wire will quickly get hot enough to start a fire.

This concept of overlapping overcurrent protection is a industry standard in electrical equipment design for good reason.

The only way a ring system makes any electrical sense is if every tap off of the ring is to a sub panel, with the very first thing being an intermediate overcurrent protection device. Anything other than that is risking an uncontrolled overcurrent and all the hazards that come with it.
OK...I'm not sure a lot of boats are really set up to your standard...especially when it comes to high amp loads like windlasses, bow thrusters...but I see and like your pointing out the redundancy of a 50 amp panel feeding much more than it is usually tasked for.
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Old 04-15-2012, 06:54 AM   #105
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"but I will say that I'm leary of CBs...they work for a dead short...most of the time.. but their failure rate in high amperage situations that aren't dead shorts resulting in hot wires/fires is just to high for my liking."


That's why they sell fuses. Cheap , easy to trouble shoot or replace.

Fast as you want , just pick the correct ones.

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Old 04-15-2012, 07:57 AM   #106
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It's completed now but here's a 'work in progress' pic of the BlueSea breaker panel I added. I needed some additional breakers for our add ons and did not want to replace the original AC/DC panel.
Fed off the main lugs in the original panel and located in the helm station.
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Old 04-17-2012, 01:54 PM   #107
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Greetings,
I fully agree with Mr. psneed and to add, ABYC "codes" are nothing of the sort. They are GUIDELINES or SUGGESTIONS so as to provide a comparison with voluntarily accepted practices. If they had ANY basis in law, the vast majority on board here would have to re-wire!
A good surveyor should apply a certain amount of discretion when passing judgement.
Definition for code - Oxford Dictionaries Online (US English)
I agree they are guidelines that insurance and surveyors do follow. Its up to the owner if the boat meets the guidelines, its up the insurance company if they want to insure and/or a buyer if they want to buy. Since bring the Eagle up to ABYC guidelines the Eagle is saver and I sleep better.
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Old 04-17-2012, 05:38 PM   #108
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I agree they are guidelines that insurance and surveyors do follow. Its up to the owner if the boat meets the guidelines, its up the insurance company if they want to insure and/or a buyer if they want to buy. Since bring the Eagle up to ABYC guidelines the Eagle is saver and I sleep better.
If you think just meeting ABYC or USCG standards makes a safe boat....yeowwwwww!!!!

And meeting those standards is really no big deal for someone in or around the boating business if you open a book/web page or two...
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Old 04-17-2012, 08:04 PM   #109
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Greetings,
Yup, they (ABYC USCG) are a minimum level BUT there has to be SOME benchmark somewhere. During a recent insurance survey I had to bite my tongue several times when the surveyor gentleman mentioned that such and such were not according to ABYC "code". Hey, I can more appreciate the fellow saying "This is not the safest" and giving his reason as opposed to "the code is...".
As it turns out, prior to the survey, I checked out every nook and cranny myself and found items that needed addressing which I will attend to that the surveyor never saw so some good DID come out of it all. But CODE....really!
Apologies to hfoster for the morph of the thread but hopefully you're absorbing some of this.
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Old 04-18-2012, 06:20 AM   #110
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If your boat is for work, you meet the USCG (usually Subchapter T ) requirements in full, or you dont get your inspection sticker.

Then you dont work.
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Old 04-18-2012, 08:14 AM   #111
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RTF. No apologies is needed My Friend. This is what the froum is about, kicking ideas around and everyone having a input. Some good always comes out in the end. Yes I am absorbing all the info that is being brought forth. All of it is great stuff.

Thanks!

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Old 04-18-2012, 10:35 AM   #112
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If you think just meeting ABYC or USCG standards makes a safe boat....yeowwwwww!!!!

And meeting those standards is really no big deal for someone in or around the boating business if you open a book/web page or two...




I did not say it made the Eagle a SAFE boat. What I said it made the Eagle a safer boat. Well if I did not spell SAFER as saver. The audit had 19 recomendations which quoted the ABYC guideline not met. It took about 20 hours and 3 grand in 60 days to meet the guidlines, if I wanted insurance. So it can be a big deal.
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Old 04-18-2012, 11:16 AM   #113
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20 hours in 60 days? Sounds like my winter work schedule...
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Old 04-18-2012, 12:29 PM   #114
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20 hours in 60 days? Sounds like my winter work schedule...

Have you ever tried to schedule a marine electrician and a diesel mechanic the middle of July? It was not my 20 hours but the 3 grand for the electrician and mechanic.
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Old 04-22-2012, 12:29 PM   #115
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Just want to say Thanks to everyone for all your input. I was very helpful

THANKS!

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Old 04-22-2012, 12:47 PM   #116
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H - Keep us apprised on your decissions as they come to fruition! - Cheers, Art
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Old 04-22-2012, 12:49 PM   #117
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Sure it will...why not? As long as every wire is fuse protected and correct size and the connections meet ABYC...what's the diff?

At least my system will be visable(traceable) for a surveyor...as opposed to a bunch of hidden wire bundles that he has no idea of what's going on when he looks at them.
Master Volt has all of the remote switching systems. ABYC cert's and EU ISO certs. New Technology is cool ,BUT the money is it worth it? KISS is cool.

Don
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Old 04-22-2012, 02:16 PM   #118
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Master Volt has all of the remote switching systems. ABYC cert's and EU ISO certs. New Technology is cool ,BUT the money is it worth it? KISS is cool.

Don
My imagined system is way simpler than whats there now...and I never imagined remote switching systems...just sub-panels instead of long wire runs and wire bundles that you can't find do-do in.
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Old 04-22-2012, 06:32 PM   #119
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Dockage at $5.00 a ft in many areas is a big money pit. FF
Oh, please tell me where I can find dockage at $5.00 a foot!! I last paid over $9.00 a foot and $12.00 a foot.....
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Old 04-22-2012, 07:28 PM   #120
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I think the Flemings are really great looking boats, well built, and hold their value pretty well...if the owner decides to sell.

My only issue with these boats, as with many other makes...is that they are not American made... I know for some people this may be a non-issue, but for me it is a touchy one.... I prefer American made products, and yes I will pay more for them. Why? Quality control, warranty, service, and all the rest.

We liveaboard our Guflstar 44 MC...built in St Petersburg, Fl...and she is well built. I guess if I was going to buy a new boat, as in really NEW...I would be looking to Hatteras or Mainship...

I guess I'm just tired of the "Made in China" label.......
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