MAXI fuse block

[sailingharry]

So my boat has a very robust and well installed electrical system. A major plus. But it still has issues, both from birth and from add-ons.


The batteries and battery switches are all tied together by a serious set of bus bars (Engine Battery, House Battery Unswitched, House Battery Switched), with ANL fuses to multiple branch circuits. Nice, clean. However, there are also many smaller wires running around in there, and they are a mess.


First, there are about 20 inline glass and blade fuses. What a mess. Things like battery sense, battery monitor, regulator power, solar inputs, sat phone power (convenient place, I guess), bilge pump, courtesy lights, the list goes on. And as is typical of inline glass fuses, most of the labels are gone or unreadable. And each has a wire going to a bunch of screws on the bus bars. I'm going to put in three blade style fuse blocks, one for each bus bar, with a single power lead to each fuse block and then label as best I can. That will make a huge difference.


But then, less of an issue but still in my mind, is some higher power stuff. Not big like windlass or starter, but bigger than a little blade fuse. The MAXI-Fuse line. Good from like 30A to 100A, or something like that. I have a 40A MAXI for the wind generator, a 40A ANL for the water generator, an 80A ANL for the battery charger. And all of these are aftermarket adds, so their leads are worked in wherever, and nothing is standard, and it's a bit of a mess. Also, ANL fuses are pricey (but hopefully you buy one and never replace it) and take up a lot of real estate.


I'd love to install a hypothetical 4 or 6 slot MAXI fuse holder. Clearly the MAXI is a fine fuse option, as Blue Seas sells a single fuse holder for fuses to 80A (wish it went to 100, as the fuse style goes that high). Think about it -- a single power line off the buss bar (yes, big, perhaps 1/0). A single small fuse block, neatly labeled. And 4 or 6 wires going to their destination. And fuses that cost 20% of an ANL fuse. What's not to like?


Problem is, no one reputable sells a MAXI holder for more than one fuse. Lots of audio stuff, big beefy wires and up to 4 fuses, but it doesn't look very "marine" and doesn't use screw/bolt style terminals. Something like this:



So after all this rambling -- has anyone come up with a neat solution for those mid range circuits? Larger than the little blade fuses, but not really the overkill of ANL size stuff?


Thanks,


Harry

[slug]

Originally Posted by sailingharry

So my boat has a very robust and well installed electrical system. A major plus. But it still has issues, both from birth and from add-ons.


The batteries and battery switches are all tied together by a serious set of bus bars (Engine Battery, House Battery Unswitched, House Battery Switched), with ANL fuses to multiple branch circuits. Nice, clean. However, there are also many smaller wires running around in there, and they are a mess.


First, there are about 20 inline glass and blade fuses. What a mess. Things like battery sense, battery monitor, regulator power, solar inputs, sat phone power (convenient place, I guess), bilge pump, courtesy lights, the list goes on. And as is typical of inline glass fuses, most of the labels are gone or unreadable. And each has a wire going to a bunch of screws on the bus bars. I'm going to put in three blade style fuse blocks, one for each bus bar, with a single power lead to each fuse block and then label as best I can. That will make a huge difference.


But then, less of an issue but still in my mind, is some higher power stuff. Not big like windlass or starter, but bigger than a little blade fuse. The MAXI-Fuse line. Good from like 30A to 100A, or something like that. I have a 40A MAXI for the wind generator, a 40A ANL for the water generator, an 80A ANL for the battery charger. And all of these are aftermarket adds, so their leads are worked in wherever, and nothing is standard, and it's a bit of a mess. Also, ANL fuses are pricey (but hopefully you buy one and never replace it) and take up a lot of real estate.


I'd love to install a hypothetical 4 or 6 slot MAXI fuse holder. Clearly the MAXI is a fine fuse option, as Blue Seas sells a single fuse holder for fuses to 80A (wish it went to 100, as the fuse style goes that high). Think about it -- a single power line off the buss bar (yes, big, perhaps 1/0). A single small fuse block, neatly labeled. And 4 or 6 wires going to their destination. And fuses that cost 20% of an ANL fuse. What's not to like?


Problem is, no one reputable sells a MAXI holder for more than one fuse. Lots of audio stuff, big beefy wires and up to 4 fuses, but it doesn't look very "marine" and doesn't use screw/bolt style terminals. Something like this:



So after all this rambling -- has anyone come up with a neat solution for those mid range circuits? Larger than the little blade fuses, but not really the overkill of ANL size stuff?


Thanks,


Harry

Go to a commercial electrical supply shop and ask about DIN rail fuse holder

[sailah]

I used a variety of these fuse blocks on my rewire. They were very easy to use and Littelfuse is a top tier industrial supplier. They also have dovetails on the body and can lock together to form blocks. The fuses are absolutely peanuts but you need to buy 10x on some of them. I stocked up with 20 lifetimes worth.

https://www.waytekwire.com/item/4600...-Fuse-Holder-/

https://www.waytekwire.com/item/4603...A-Fuse-Holder/

These are pretty neat looking and have bus bars already and splash cover included, I wish I saw them because they tick a lot of boxes

https://www.waytekwire.com/item/4632...-Fuse-Holder-/

Explore around on Waytek site they are a lot of options without spending marine prices and quality is on par with anything I've seen.

https://www.waytekwire.com/products/1612/Fuse-Blocks/

I also bought all my terminal blocks from Eaton, example is 6 position

https://www.mouser.com/ProductDetail...dYkdDrVdz08%3D

[sailah]

I also bought a bunch of single fuse holders

https://www.waytekwire.com/products/...s/&pageSize=36

The pricing on inline fuse holders is crazy and they are extremely nice quality for low amp protection

https://www.waytekwire.com/item/4648...-Fuse-Holder-/

[Kokanee]

Blue Seas have a combined fuse block with 4 AMI/MIDI fuses up to 200 amps along with 6 ATO/ATC fuses up to 30 Amps.

https://www.bluesea.com/products/774...150_Fuse_Block

[CharlieJ]

Here is a newly introduced MEGA, not MIDI, fuse holder product from Victron Energy that you might find as a good alternative.https://tinyurl.com/y9oakzxf. MEGA Fuses are rated up to 300A @ 32VDC with an AIC of 2000A.

[sailingharry]

Sailah,


Nice links. Thanks!


Your picture shows some copper bus bars. I would love to do that. To me, making a 3" connector out of 1/0 wire with two lugs is dumb. Expensive, hard to make, takes up space. Where did you get them? Did you make them? With what? Sure would be nice to find tin plated copper bar 1" x 1/8" x several feet. You might even try to find a way to connect your battery switch to the fuse block with it, and the Balmar shunt to the ground bus. (By the way, your house ground wire should go to the shunt, not the bus).



Your fuse panel is VERY nicely done, but exactly what I DON'T want. Rather than a bus bar, with a bunch of leads to each fuse block, I'd like to have them ganged into one. So a copper bar running along the input of the fuse blocks, and a single wire into it. So you would need a 6" copper bar running down the left side, and eliminate 4 short copper jumpers and the bus strip (while also significantly reducing risk of shorts, because it would all be inside the covers). It also reduces the number of connections (and risk of resistance, failure, etc) dramatically.



Playing around on Waytek, I found this:
https://www.waytekwire.com/item/4554...-FHZ-Series-5/
This could be it. A single wire goes into the bottom bolt, an then you have 4 fuse locations. The fuses are bolted on (like the MRBF). The fuses come from 40A to 400A (I think -- I forget exact range). The holder is $50, the fuses are under $5. They also sell a slightly larger unit that holds 6 fuses. Waytek seems to never share max wire sizes, so I've got a question in to them.


You mentioned a lifetime supply of fuses. One thing I plan on doing is a careful analysis of loads and fuses, with the objective of reducing the variety. For instance, my windlass and power winch both have local breakers at 80A (IIRC) to protect the unit, but are fed by 1/0 cables because of voltage drop. The fuses at the distribution panel are 80A also, but they could easily be 200A to match some other fuses (1/0 is rated to 285A), and I won't need to carry 80A fuses.

[Frankly]

https://www.onlinemetals.com/en/buy/...kaAvSEEALw_wcB


https://www.cruisersforum.com/forums...ture24349.html


Frankly

[sailingharry]

Frankly,


Great source. Now I wish they had it in 1/8 (I see you had to use a short section of un-plated copper in there). But still, great product at a really great price.


Your "fuse block" probably doesn't meet some obscure ABYC code (like, say, using products from ABYC supporting members), but it sure looks well done. Very proper!


Your nuts and bolts are even copper (or an alloy).



Thanks again,


Harry

[CharlieJ]

sailingharry #9:

Great source. Now I wish they had it in 1/8 (I see you had to use a short section of un-plated copper in there). But still, great product at a really great price.

As a first order analysis: Consider ampacity of bus bars and ¼" x 1" bus bars have a cross sectional area > Boat Cable AWG 4/0 cross sectional area whereas ⅛" x 1" bus bars have a cross sectional area that lies between Boat Cable AWG 2/0 and AWG 4/0 cross sectional areas. Simplified, bus bar ampacity is directly related to its cross sectional area.

However, bigger is better, not only for ampacity but also for heat dissipation.

The IEEE states a busbar should be rated at the highest amperage passing through any section of the busbar, with a maximum of a 50° C rise in temperature from an ambient temperature of 50° C.

. Note that the Blue Sea Systems PowerBar is rated at 600A and has a cross sectional area of 1" x ¾" and is designed for a 40C temperature rise above ambient.

To gain more insight about the mundane subject of bus bars, I recommend you take a look at the tech docs here: https://www.bluesea.com/support/articles/Busbars. These tech docs discuss how to optimize the use and capability of a bus bar through conductor placement, orientation, etc.

Your "fuse block" probably doesn't meet some obscure ABYC code (like, say, using products from ABYC supporting members), but it sure looks well done. Very proper!

Nothing "obscure" about the ABYC Standards. They are the Standards cited in the CFR, becoming homogenized with the European ISO Standards and used by surveyors and therefore are an integral part of the boat insurance process. Your parenthetical comment is way off base...there is absolutely no truth in your allegation.

I would encourage you to participate in the development and improvement of the ABYC Standards by getting on the mailing list for those Standards that interest you. As a participant, you will receive draft copies of those Standards up for review and will be encouraged to comment on them. Your comments will be discussed and adjudicated during regularly scheduled meetings of the various Project Technical Committees.

The POC is the ABYC Technical Director, Brian Goodwin who can be reached at
410-990-4460 x115.

[Frankly]

Look around there are several sources of copper. I think my lightning ground plate came from GA or NC. The bus bar material I used came from scrap metal yard (20 year ago purchase), was not plated/ tinned so I had to do that manually. The fasteners are silicone bronze (95% copper but 5 X the resistance), chosen to avoid SS to SS galling. Right, no UL listing anywhere on the assy.

[sailah]

Originally Posted by sailingharry

Sailah,


Nice links. Thanks!


Your picture shows some copper bus bars. I would love to do that. To me, making a 3" connector out of 1/0 wire with two lugs is dumb. Expensive, hard to make, takes up space. Where did you get them? Did you make them? With what? Sure would be nice to find tin plated copper bar 1" x 1/8" x several feet. You might even try to find a way to connect your battery switch to the fuse block with it, and the Balmar shunt to the ground bus. (By the way, your house ground wire should go to the shunt, not the bus).



Your fuse panel is VERY nicely done, but exactly what I DON'T want. Rather than a bus bar, with a bunch of leads to each fuse block, I'd like to have them ganged into one. So a copper bar running along the input of the fuse blocks, and a single wire into it. So you would need a 6" copper bar running down the left side, and eliminate 4 short copper jumpers and the bus strip (while also significantly reducing risk of shorts, because it would all be inside the covers). It also reduces the number of connections (and risk of resistance, failure, etc) dramatically.



Playing around on Waytek, I found this:
https://www.waytekwire.com/item/4554...-FHZ-Series-5/
This could be it. A single wire goes into the bottom bolt, an then you have 4 fuse locations. The fuses are bolted on (like the MRBF). The fuses come from 40A to 400A (I think -- I forget exact range). The holder is $50, the fuses are under $5. They also sell a slightly larger unit that holds 6 fuses. Waytek seems to never share max wire sizes, so I've got a question in to them.


You mentioned a lifetime supply of fuses. One thing I plan on doing is a careful analysis of loads and fuses, with the objective of reducing the variety. For instance, my windlass and power winch both have local breakers at 80A (IIRC) to protect the unit, but are fed by 1/0 cables because of voltage drop. The fuses at the distribution panel are 80A also, but they could easily be 200A to match some other fuses (1/0 is rated to 285A), and I won't need to carry 80A fuses.

You are correct about House bus, in that mockup I had not finished the connections was more about trying to fit it all on plywood. I attached final pic.

I got the copper bar from McMaster Carr, 1/4" thick, 1' long and cut to fit. I wish I had gotten plated as I suspect it will corrode over time but so far seems fine. Easy enough to swap out if it does. I guess I could always polish them up and then plate myself.

https://www.mcmaster.com/8964k8
https://www.mcmaster.com/88865k621

Regarding fuses, I just bought the minimum number required and keep a handful of each amp rating in a ziplock bag. Takes up no space.

I totally agree with you about finding a cleaner solution. I was on a hard target search for fuse holders and did not see those nicer engineered solutions you found. I likely would have gone that route. I had a collection of parts already so I filled in the gaps where needed.

[sailingharry]

Charlie,


I'm an engineer, so I get much of this. I also have a complete set of ABYC standards, read them, and work toward compliance (although on a 20+ year old boat, it's often a challenge). Just having read them puts me way ahead of most DIY boaters -- referencing them often is an even bigger plus!



Your discussion on copper equivalence is correct, but bars that large are not always required. A bus bar that distributes hundreds of amps, certainly. A tie bar that feeds from the bus bar into a 100A fuse doesn't need to be that large (it needs to be correctly sized, but probably not 1" x 1/4").



I don't quite agree about ABYC not being obscure. My current concern, because Maryland came close to legislating compliance, is CO detectors. So we would have had a law pointing at ABYC, that simply said "a UL compliant marine detector" an the UL requirement was quite unclear. A $30 CO and fire combo detector from Kidde is fully compliant for an RV or a beach cottage, both of which suffer from much of the same environmental conditions, appears to not be compliant. There is only one (possibly two, but the other I think doesn't meet the rules) compliant manufacturer at triple the cost. And no one can explain the difference.


Ten years ago, the AIC rules were a mess. They didn't apparently didn't apply to fuses, couldn't comply with small wires tied directly to batteries (like a battery charger), and they if they did apply to fuses, they stipulated crazy requirements for every fuse on the boat, including the little glass fuses on the back of electronics. The current (starting in 2016) regs are a HUGE improvement.



But you are well qualified to comment on the installation in those pictures. Does a home-built "fuse block" meet all the requirements for ABYC? I think his work looks good -- but is it compliant?


Harry

[CharlieJ]

sailing harry #13

I'm an engineer, so I get much of this. I also have a complete set of ABYC standards, read them, and work toward compliance (although on a 20+ year old boat, it's often a challenge). Just having read them puts me way ahead of most DIY boaters -- referencing them often is an even bigger plus!

You are certainly one of the few!

Your discussion on copper equivalence is correct, but bars that large are not always required. A bus bar that distributes hundreds of amps, certainly. A tie bar that feeds from the bus bar into a 100A fuse doesn't need to be that large (it needs to be correctly sized, but probably not 1" x 1/4").

Certainly, but the concept and first principles are still valid. My point was, there are design issues that must be thought through like ampacity and heat dissipation.

I don't quite agree about ABYC not being obscure. My current concern, because Maryland came close to legislating compliance, is CO detectors. So we would have had a law pointing at ABYC, that simply said "a UL compliant marine detector" an the UL requirement was quite unclear. A $30 CO and fire combo detector from Kidde is fully compliant for an RV or a beach cottage, both of which suffer from much of the same environmental conditions, appears to not be compliant. There is only one (possibly two, but the other I think doesn't meet the rules) compliant manufacturer at triple the cost. And no one can explain the difference.

I am not a CO Detector expert but there are some requirements from ABYC A-24 that I doubt the big box CO would meet:
A24.5 DESIGN AND CONSTRUCTION
24.5.1 Detectors shall be certified by an independent third party to meet the requirements of UL 2034, Single and Multiple Station Carbon Monoxide Detectors including the applicable sections pertaining for use on recreational boats.
24.5.1.1 Design operating temperature range = -22°F to +158°F (-30°C to +70°C).
24.5.2 An audible alarm shall be provided.24.5.2.1If detectors include a switch to mute only the audible alarm, then warnings or other means shall be provided to protect such a switch from casual use, and
24.5.2.1.1 the switch shall not reset the detector, and
24.5.2.1.2 the switch shall not mute the alarm for more than six minutes.
24.5.3 There shall be no power switch on the detector.
24.5.4 A non-mechanical indicator, e.g., some type of visual electrical indicator (lamp, LED, LCD, etc.), shall be provided on the detector to indicate that it is in operation.
24.5.5A circuit self-check shall be provided that will also give an alarm for an electrically defective sensor.
24.5.5.1 A testing procedure or test switch shall be provided for checking the alarm circuitry.
24.5.6 Detectors shall be designed and marked as drip proof or watertight as per UL 2034, Single and Multiple Station Carbon Monoxide Detectors including the applicable sections pertaining to use on recreational boats.
24.5.7 Detectors shall be powered by the boat’s DC electrical system, or
24.5.7.1 by a self-contained battery.


So, a quick reading certainly implies that there are a few (bolded above) additional certification tests to be performed for a "marine rated" CO detector.

Ten years ago, the AIC rules were a mess. They didn't apparently didn't apply to fuses, couldn't comply with small wires tied directly to batteries (like a battery charger), and they if they did apply to fuses, they stipulated crazy requirements for every fuse on the boat, including the little glass fuses on the back of electronics. The current (starting in 2016) regs are a HUGE improvement.

Absolutely agree. That is why the Standards are on a review cycle so that they do not stagnate. BTW, the AIC requirements for Main and Branch OCPD are still not correct.

But you are well qualified to comment on the installation in those pictures. Does a home-built "fuse block" meet all the requirements for ABYC? I think his work looks good -- but is it compliant?

Hard to tell. He is compliant with the plexiglass shielding the B+ components but I am unfamiliar with the black covers to the right of the bus bar. In general, fuses and fuse holders are third party tested, and listed as a "system". So if the black covers are covering the fuses in their designed fuse holder than the assembly appears compliant. If the fuse holders have been eliminated, than the assembly is not compliant.

Here is a new fuse holder/bus bar system from Blue Sea Systems that uses MRBF:
https://tinyurl.com/ya46xcn9

Consider contributing to the effort of continuous improvement of the Standards.

[sailingharry]

Regarding contributing. As you can tell, I do think about this stuff. And as a licensed engineer, I also have some theory (but it's generalized theory -- they certainly didn't teach to ABYC!). So I might actually have valuable comments to make. Do they allow non-ABYC members to contribute?