new breaker/switch panel came in - have questions

[workinprogress]

Shakespeare, I snagged some information you gave on a different post to come up with just enough data to think the people at Blue Sea Systems are putting out an improperly designed product. I know, that is almost blaspheme. Someone smarter than me jump in and help me out here.

I purchased this circuit breaker/switch panel.
http://bluesea.com/category/7/27/products/4386
It came set up to have one positive feed, wired through 16 ga/105 deg wire, with all current run consecutively from one positive breaker terminal to the next, and so on. This panel is rated at 90 amps. (6 x 15amps) Using the formula from the earlier post, your wire should have an ampacity rating of 112.5 amps (90 amps x 125%) but 16 ga/105 deg wire is only rated to 25 amps. If I figured that correctly, that ain't even close.

Shouldn't I bring a main feeder into a busbar with larger wire and fuse protection, and come off of the small terminals with individual positive feeds to each positive 15 amp fuse terminal, making my wire ampacity requirement only +/- 19 amps, staying within the limits of the 16ga wire?

This is somewhat of an unneccessary question because I will be running probably all 3 amp breakers, which would keep my ampacity requirements at 22.5 amps (125% of 18 amps) but if my yet unpurchased gps system needs 6amp instead of 3amp circuit protection I am at 26 amps, again exceeding the rating of the supplied wire if I do not split each individual circuit with a busbar.

I know Blue Sea Systems products are as reputable as you can get but it seems to me they goofed on this "in tandem" setup. You guys have taught me enough to question some things, but I am still too new at this to be sure about what I am talking about. After all, who am I to question Blue Sea Systems?

[NOTHING ELSE MATTERS]

You will never reach or exeed the total amps from your switch.To do that you have to power everything at once in order to draw the max rating current for each item you have hooked up.You stated that there is one hot wire going to all brakers.Is it a continous wire on jump loops.Either way is fine, but loops would be better.Now, don't forget a wire that is rated let's say for 10 amps, if you pass 20 amps through that wire, it will not melt or short out, your fuse will take care that, so the wire would not melt.So the way it is, it's fine , don't sweat it.

[workinprogress]

It's jump looped NEM, can you explain the difference to me between how the continuous wire and jump loops work? Thanks.

[Shakespeare]

I went to the product literature and here's the bad news... it says the "Panel Cumulative Rating is 45 Amperes".

You can't multiply the total number of breakers by 15 and expect the total panel ampacity to be the result of that calculation.

How did you determine that the panel wire was 16ga? Was it stamped on the insulation?

With that being said I am surprised that that a larger wire is not being used to daisy chain the breakers. I believe that Blue Sea is banking on the idea that a majority of the circuits will not be fully loaded concurrently. But even then with 16 ga wire rated at 25 amps this does not sufficiently cover a 45 amp panel.

I would suggest contacting Blue Sea tech support and question how a 25amp wire can support a 45 amp panel and see what they say.

Looking at your loads I don't think you're going to be in any sort of jeapordy. Your GPS might be fused for 6 amps but it won't be pulling that. This may work out fine for you but I agree it is a bit deceiving.

Mike C.

[NOTHING ELSE MATTERS]

Shake, isn't the Cumulative Rating , the surge rating?
That panel, would never draw 45 amps at once.Can you explain it a bit , cause my electical engineer degree is sitting somewhere in a draw, never used it anyway, after college went to restaurants and woodworking.Go figure. 001

[Shakespeare]

Shake, isn't the Cumulative Rating , the surge rating?
That panel, would never draw 45 amps at once.Can you explain it a bit , cause my electical engineer degree is sitting somewhere in a draw, never used it anyway, after college went to restaurants and woodworking.Go figure. 001


You are correct NEM. Just because a panel is rated for a certain capacity doesn't mean you want to load it for that for an extended amount of time. Regardless, the feeder wire and overcurrent protection should be sized for the capacity of the panel and that will take care of continous loads and surges. Using the 125% safety factor, you wouldn't want more than 36 amps continous load. But still, the 16 gauge wire daisychaining those breakers isn't sufficient for even that. It will be interesting to see what Blue Sea's explanation is.

Mike C.

[workinprogress]

Thanks guys, I just want to make sure I only wire the boat once, and unlike you NEM, I don't have an EE degree. (nor do I know anything about restaraunts or woodworking--haha) If you give me a little bit of education, apparently it only makes me some kind of schizophrenic wack job. The main thing I wanted to get from this post is this simple question.
I found out what a busbar was 2 weeks ago. I bought a busbar. I want to need to use a busbar. Do I?
Never mind the ampacity rating of the wire, if I run everything jump looped, don't I turn troubleshooting into a nightmare vs. the individual component isolated feeder/breaker setup. Thanks again for humoring my inexperience.

[NOTHING ELSE MATTERS]

No body is humoring your inexperience.I was in your shoes few years back, and beleive me i understand where you coming from and what you are going through.This is for you bud, 012

[workinprogress]

No body is humoring your inexperience.I was in your shoes few years back, and beleive me i understand where you coming from and what you are going through.This is for you bud,

Didn't mean that sarcastically, I just know where my electrical AND boating knowledge rates. I do appreciate all the help. Anyway, if you can't laugh at yourself, you can't laugh at anybody else, can ya?

[NOTHING ELSE MATTERS]

ROTFLMAO ROTFLMAO ROTFLMAO ROTFLMAO ROTFLMAO ROTFLMAO ROTFLMAO ROTFLMAO ROTFLMAO

012 012

[workinprogress]

You guys are great help, but you keep skipping this part.

I found out what a busbar was 2 weeks ago. I bought a busbar. I want to need to use a busbar. Do I?
Never mind the ampacity rating of the wire, if I run everything jump looped, don't I turn troubleshooting into a nightmare vs. the individual component isolated feeder/breaker setup.

[Shakespeare]

I thought your original concept was to allow the feeder wire to hit the buss bar then on to the panel.

If you use the buss bar then you can hook your electronics to it because they will have inline fuses. The breaker panel can protect your pumps. Somewhere in there you have to put in your lighting circuit. If you have a spare breaker, then that's where I would put it.

If you have enough circuit breakers to cover everything, then the buss bar is unneccessary... or you can feed the bussbar from one of the breakers. Several different options here.

After thinking about your panel dilemna I believe everything is going to be ok based on the loads that you have. My whole boat; nav lights, bilge, aerator, spreader lights, VHF, GPS/FF is all on one 20 amp main fuse. I'm probably at the edge as far as current draw but my point is with your new electrical scheme you should be more than covered and that small gauge wire that daisy chains the breakers should be a non-iissue. I'm going to contact Blue Sea a little later today just to get their official word on the daisy chained wire.

Your second question about "jump loop". That's where each breaker receives its hot feed, via the daisy chain. The branch circuits are on the downstream side of each breaker. Is this making any sense?

I'm looking at page 2 of the instructions for your panel.

http://bluesea.com/files/resources/instructions/6493.pdf

Mike C.

[Shakespeare]

workinprogress... hang tight ... I'm going to draw up a schematic and maybe that will help to answer your questions.

Mike C.

[Shakespeare]

Ok, here's a typical way to wire standard boat components. This isn't cast in stone.. there are several different schemes that can be employed, but hopefully this will illustrate the concept.

Here's a direct link to the picture; http://i235.photobucket.com/albums/ee78/CSO_Shakespeare/218DLV/BoatWiring.jpg

Alternatively, you could feed the positive buss bar straight from the same feeder that is supplying the breaker panel. Just make sure any downstream devices off the buss bar are adequately fused, the wire supplying the buss bar is rated for the capacity of the main fuse, and the buss bar itself is rated high enough to support the maximum capacity of the main fuse.

Mike C.

http://i235.photobucket.com/albums/ee78/CSO_Shakespeare/218DLV/BoatWiring.jpg

[workinprogress]

Thanks Mike, that is very clear. I had in my mind a little different setup. Let me lay out the whole thing, and if there are holes to be shot in my plan, shoot away.
I plan on connecting two pos and two neg main wires at the battery. (single, 12v)
One pos and one neg go direct to motor. (25hp pushbutton on the motor electric start)
Other pos feeder (8ga) goes to pos buss bar, with 30amp fuse in this feeder between bat and buss bar.
Rather than use the daisy chain to supply pos to each breaker, I think I will supply pos to each individual circuit breaker from an indivdual line from the buss bar. My thought on doing this is if I get some kind of wire short between the first and second breaker pos feeds, I loose all the other downstream circuits. If I connect each pos circuit breaker terminal individually, any short will result in only the isolated loss of that particualr circuit.
The buss bar I have has 10 connections, my breaker/switch panel has only 6. I may not even use all 6 circuits on the panel. This leaves ample connections from the buss bar for vhf, gps, or whatever else I might want to use with its own inline fuse.
By the way, besides the main 8ga line, I am using all 14ga/105 degree. Way more than these loads require, I just liked the idea of the higher tensile strenth.

OK, that's the plan. If there are flaws, please identify them. I will take it as constructive assistance, which I know is how you guys mean it. Thanks again.


How did you determine that the panel wire was 16ga? Was it stamped on the insulation?
I forgot to answer that. Yes, it was stamped on the insulation.

[Shakespeare]

This statement confuses me;


My thought on doing this is if I get some kind of wire short between the first and second breaker pos feeds, I loose all the other downstream circuits.

If you get a short on the line side (feed side) of the circuit breakers, it will be the main fuse that blows... regardless if you use the factory installed daisy chain configuration or if you rewire the line side distribution to the breakers from the buss bar. None of the panel breakers will trip nor will there be any cascading faults... it's the main fuse that will see the short circuit. Does that make sense?

Mike C.

[Shakespeare]

I spoke with Blue Seas. They said the wire that daisy chains each of the breakers is supposed to be 12 gauge.

Please look at page 2, section 3 of this document;

http://bluesea.com/files/resources/instructions/6493.pdf

The wire in question has a footnote of '1'. I'm told it is the red wire. Is that the wire that you identified as the 16 gauge wire?

Mike C.

[workinprogress]

I shouldn't have used the word short. If I get a loose wire, bad connection, etc..., everything downstream goes dead.

[Shakespeare]

I shouldn't have used the word short. If I get a loose wire, bad connection, etc..., everything downstream goes dead.


Ok, now your statement makes sense. All I can say is if it makes you feel better about things then go for it (the rewiring). If you do rewire the line feeds to the breakers then the small wire gauge becomes a moot point. But it sounds to me like the factory made an "ut oh".

Mike C.

[workinprogress]

OK, this is going to make me look more than a little bit foolish, but in all fairness to Blue Seas I need to set the record straight. When I originally looked at the main positive feeder wire, I thought it actually looked identical to the 14ga marine grade wire I had, and I began looking for the wire size on the wire. It wasn't listed on the main feeder, and I began tracing the daisy chain, and one after the other they had been cut and connected in such a way the gauge label was obscured. I hopped right over to the negative terminal wiring, which looked to me to be identical wire. That is actually where I was able to read the 16ga label. There is no visible difference in the diameter between the 14ga primary wire I have and the main pos feeder, so in the interest of being thorough tonight I stripped off the insulation from the end of each. I was surprised to see the wire on the Blue Seas panel was noticably bigger. I took apart one of the insulated connectors, revealing a 12ga label on the wire. My apologies to Blue Seas and Shakespeare. Blue Seas for falsely acusing you of putting out an improperly designed product, and Shakespeare for sending you on a wild goose chase armed with bad information.

The wire size issue is gone. Do you guys think wiring each individual breaker with its own pos feeder from the buss box is ludicrous?

[Shakespeare]

workinprogress... no apologies necessary. Being inquisitive is a good thing. Being methodical and deliberate is even better. Do you know how many filaments Edison went through before he could get a light bulb to stay lit for an extended amount of time. Well 006 the answer escapes me at the moment but it was a lot... a whole lot. The point being is we all learned something. And that my friend is the best of things.

To answer your question, IMO I think it unnecessary to change the breaker panel wiring. It has been designed by engineers, tested, and hopefully market proven. If it shows weakness in the future then it can be addressed at that time. What I do think is you have a lot of work ahead of you getting that sucker wired and ready to do some fishing... so lets get going! thumbsup

Mike C.

[workinprogress]

Thanks for sweeping that one under the rug. I am going to wire off of the diagram you posted, but that leads to a few more questions.
I'm going to run an 8ga feeder wire (allowable ampacity-80a) with a 30 amp fuse. (although the fuse block is rated up to 80a--just change fuses). The buss bar is rated to 100a. The breaker panel is only rated to 45amps. It looks like your diagram has me go dierect to the breaker panel-then from the end of the daisy chain at the circuit breaker to the buss bar, limiting future expansion to a 45amp max, less the load used through the panel. Would it not make more sense to go direct from the battery to the buss bar, and then to the circuit panel from one of the individual terminals on the busbar, making the system rated to an 80amp max, less the load drawn through the panel?
Future expansion may be a moot point, after all it is just a j16.
I notice you have a 3-way switch on the bilge--this is not necessary is it?

[Shakespeare]

Would it not make more sense to go direct from the battery to the buss bar, and then to the circuit panel from one of the individual terminals on the busbar, making the system rated to an 80amp max, less the load drawn through the panel?

There's no problem feeding the buss bar first and hopping off to the panel second. Your feeder wire size and overcurrent protection is in order and the rating of the buss bar will support it. However, the panel should be mounted in close proximity to the buss bar when you do this or you will end up with a length of wire that is not adequately protected. If you were to mount the panel some distance away from the buss bar, then you would want to install proper fusing to protect the wire feeding the panel, just like you did at the battery with the main fuse.


I notice you have a 3-way switch on the bilge--this is not necessary is it?
If you don't have an automatic bilge pump then the 3-way switch is unneccessary. Most of the newer skiffs come with the automatic style pump which turns on in timed intervals (in the auto mode) to check for water in the bilge.


Mike C.

009 This post edited to provide better clarification and the removal of some inacurate statements.