What am I not understanding about ANL fuses

[Marco Flamingo]

My house batteries are in two banks, each with an ANL 250 amp fuse right by the post. The prior owner left a tool box with lots of electrical stuff, but no 250A replacement fuses. Looking on Amazon, prices are all over the place for these fuses. Here is a single 250A fuse for $38. Here is a pack of 10 for $10. While I hope to never need 10 fuses, is there some invisible difference on these that makes one brand worth 40X the other brand?

 

[twistedtree]

UL Recognized is one difference. Also, some ANL fuses are ignition protected and others are not. That matters depending on the boat and location of the fuse. Also perhaps the AIC rating for the fuse. I'm not sure if that's part of the ANL spec, or if it's different for different ANL fuses.

 

[SteveK]

My house batteries are in two banks, each with an ANL 250 amp fuse right by the post. The prior owner left a tool box with lots of electrical stuff, but no 250A replacement fuses. Looking on Amazon, prices are all over the place for these fuses. Here is a single 250A fuse for $38. Here is a pack of 10 for $10. While I hope to never need 10 fuses, is there some invisible difference on these that makes one brand worth 40X the other brand?

on amazon there are re-sellers. They buy a 10 pack, repackage and advertise singles for a higher price. capitalism.

 

[Choices]

Try Fuseco in Houston.
They also carry the Japanese glass fuses for Northern Lights generators. Try finding one of those.
I bought a box of ten, cartoon qty. You never know.

 

[Benthic2]

The sizes seem different:

Item Dimensions LxWxH 5 x 3.5 x 0.25 inches

vs

Product Dimensions ‎3.15 x 0.39 x 0.98 inches

 

[Choices]

Bottom is a metric fuse. Do you have an old fuse you want?

 

[FF]

ONLY certain fuses can handle stopping a huge overload.


Many folks will use a class T .

 

[diver dave]

ONLY certain fuses can handle stopping a huge overload.


Many folks will use a class T .

Actually, its more than that. The fuse must maintain its “integrity”. Must stay intact, and not liberate glass, molten metal, etc.
A ANL will successfully break the circuit, but high overloads will not be contained; a failure.

 

[ksanders]

ANL fuses are typically rated at 6,000 amps AIC Amps Interrupting Current, which meets the ABYC requirements for battery bank circuit protection.

The problem with buying a non name brand is you cannot be sure that they are tested to meet the AIC rating and you may not know if the operating curve is appropriate for this kind of circuit protection.

What is the curve? The curve is a graph that specifies the inverse time overcurrent characteristics of any overcurrent protection device. The idea is that the more fault current, the faster the device operates. Those exact paramaters are defined by it's curve rating.

I am a fan of Blue Sea fuses because I know that they are designed to meet the requirements for marine system protection.

 

[Bacchus]

ANL fuses are typically rated at 6,000 amps AIC Amps Interrupting Current, which meets the ABYC requirements for battery bank circuit protection...

...I am a fan of Blue Sea fuses because I know that they are designed to meet the requirements for marine system protection.

Kevin,
I'm no expert on this but have been researching in prep for batty replacement on my house bank. As I understand it the ABYC reqmt for protecting batty banks depends on the bank size. I believe ANL and MRBF fuses are limited to smaller batty banks and only Type T will satisfy ABYC for larger banks.
Here's a quote I saved from another post that is the origin of my current thinking. I'll attach an article by Steve D Antonio that elaborates but I believe supports this as well.

"The operative language is found in the 2018 section on "Main Battery Overcurrent Protection" in E-11. Following is the quote:
"11.10.1.2.3 For batteries or battery banks with a CCA rating greater than 2200 CCA, or 500 amp hours, battery overcurrent protection shall have a minimum ampere interrupting capacity (AIC) rating at least as great as the battery manufacturer’s short circuit rating or be rated at a minimum of 20kA at 125 VDC or higher."

Impact:
A boat with no more that two 8D batteries in a battery bank will not be affected, since the bank is less than 2200CCA or 500aHr.
Any boat with six, 6V golf cart batteries or more in a bank, or with more than two 8Ds in a bank, is affected.
Any combination of batteries of any size can trigger this requirement, including banks of Group 31 and Group 34 batteries.
Those currently protected with Type MRBF Fuses will no longer meet the criteria of the standard, since Type MRBF fuses are not rated at 20kA AIC."


I believe MRBF fuses are rated at 10,000AIC and they don't meet the higher reqmts for larger banks so I'm sure the ANL's (rated at 6,000 AIC) won't meet it either.

 

[ksanders]

Kevin,
I'm no expert on this but have been researching in prep for batty replacement on my house bank. As I understand it the ABYC reqmt for protecting batty banks depends on the bank size. I believe ANL and MRBF fuses are limited to smaller batty banks and only Type T will satisfy ABYC for larger banks.
Here's a quote I saved from another post that is the origin of my current thinking. I'll attach an article by Steve D Antonio that elaborates but I believe supports this as well.

"The operative language is found in the 2018 section on "Main Battery Overcurrent Protection" in E-11. Following is the quote:
"11.10.1.2.3 For batteries or battery banks with a CCA rating greater than 2200 CCA, or 500 amp hours, battery overcurrent protection shall have a minimum ampere interrupting capacity (AIC) rating at least as great as the battery manufacturer’s short circuit rating or be rated at a minimum of 20kA at 125 VDC or higher."

Impact:
A boat with no more that two 8D batteries in a battery bank will not be affected, since the bank is less than 2200CCA or 500aHr.
Any boat with six, 6V golf cart batteries or more in a bank, or with more than two 8Ds in a bank, is affected.
Any combination of batteries of any size can trigger this requirement, including banks of Group 31 and Group 34 batteries.
Those currently protected with Type MRBF Fuses will no longer meet the criteria of the standard, since Type MRBF fuses are not rated at 20kA AIC."


I believe MRBF fuses are rated at 10,000AIC and they don't meet the higher reqmts for larger banks so I'm sure the ANL's (rated at 6,000 AIC) won't meet it either.

That is really interesting and honestly I had not looked it up! Thanks!@

I have used the terminal mounted Blue Seas fuse system for years and never realized that they might not meet the AIC rating of my bank.

But... On my bank of two parallel 420AH strings I do provide overcurrent protection between the strings, which probably satisfies the AIC rating requirement, so I am guessing that my installation is compliant since electrically it is two separate banks that are individually protected

Geez, one more thing to keep me up at night...

 

[Bacchus]

That is really interesting and honestly I had not looked it up! Thanks!@

I have used the terminal mounted Blue Seas fuse system for years and never realized that they might not meet the AIC rating of my bank.

But... On my bank of two parallel 420AH strings I do provide overcurrent protection between the strings, which probably satisfies the AIC rating requirement, so I am guessing that my installation is compliant since electrically it is two separate banks that are individually protected

Geez, one more thing to keep me up at night...

Kevin
Your thinking is similar to what I had as another means of meeting the intent of the reqmt.
I was thinking of using a couple MRBFs (@ 10,000 AIC) mounted on the batty terminals for the parallel jumpers between GP31s.
I just don't have a convenient place to mount a Type T holder & fuse close to the batteries. Im sure its possible given time & effort but the MRBF approach is simpler... following the KISS priciple.

 

[diver dave]

Yeah, i put a MRBF on each battery; so, not in a position to break the entire bank current.
It also solves the fault risk of a battery internal short. Which a single bank fuse does not.

 

[ksanders]

Kevin
Your thinking is similar to what I had as another means of meeting the intent of the reqmt.
I was thinking of using a couple MRBFs (@ 10,000 AIC) mounted on the batty terminals for the parallel jumpers between GP31s.
I just don't have a convenient place to mount a Type T holder & fuse close to the batteries. Im sure its possible given time & effort but the MRBF approach is simpler... following the KISS priciple.

When I replaced my batteries in 2020 I never knew that the Blue Seas MBRF did not meet the must be new AIC requirements. Your post was the first I'd heard about it.

My thought was just that if... If one string shorted I did not want the other string feeding that short with current and causing a fire.

I use the Blue Seas terminal mounted fuses for the same reason. My battery boxes are in the lazarette and there is just not a good place for a fuse holder that is not mounted to the deck. I did not want to do that because I did not want to risk my house bank if that area got wet.

 

[Scottwb96]

Marco-
the 10-pack you found is from Skar Audio (car audio manf.)... Aside from the specs listed on Amazon, I don't see much more listed, even on their site...

 

[Bacchus]

When I replaced my batteries in 2020 I never knew that the Blue Seas MBRF did not meet the must be new AIC requirements. Your post was the first I'd heard about it.



My thought was just that if... If one string shorted I did not want the other string feeding that short with current and causing a fire.



I use the Blue Seas terminal mounted fuses for the same reason. My battery boxes are in the lazarette and there is just not a good place for a fuse holder that is not mounted to the deck. I did not want to do that because I did not want to risk my house bank if that area got wet.

Kevin
From what I've seen I believe the large batty bank fusing reqmts was added or updated in 2018 so not unreasonable to take some time for the word to spread... especially since ABYC charges for Stds & updates.