Still stuck on a fuse !!!!

Urge38 · May 30, 2023

Hi there people.

yeah yeah, I know, get over it lol
But I am one for the little detail and I cant help but wonder.

My dilemma is, choosing the correct class T fuse

Most if not all, Class t rated fuses I've seen have a interrupt capacity of 20,000A DC for my 400A rated fuse. Littelfuse JLLN 400A or Bussman JJN 400

ONLY the manufacture of my inverter states a 50Ka or 100Ka interrupt rating.

the 20,000A fuses are not even half the interrupt capacity of what I need.

would anyone know what the short circuit currant for a 400a battery pack (I have 4 100a rack batteries)

Bluedog225 · May 30, 2023

Following

SeaGal · May 30, 2023

Urge38 said:
would anyone know what the short circuit currant for a 400a battery pack (I have 4 100a rack batteries)

Currants... as in red for positive and black for negative?

mikefitz · May 30, 2023

Perhaps the inverter data was referring to the AC fuse interrupt rating.

Since the usual 20kA rating is at 130v or higher, I would expect the current would be higher at lower voltages.

SamDeleted · May 30, 2023

SeaGal said:
View attachment 151120

Currants... as in red for positive and black for negative?

Also greens the earth

You've got a full basket as it were

400bird · May 30, 2023

Carlingtech/Midnite solar offer a breaker with a 50,000 amp interrupt rating. Midnite only carries them up to 250 amps, you might be able to find them from another reseller at 400 amps.

What inverter are you running that runs at 400 amps?

Urge38 · May 30, 2023

SeaGal said:
View attachment 151120

Currants... as in red for positive and black for negative?

its no fun being born with dyslexia, I can only do my best

Urge38 · May 30, 2023

400bird said:
Carlingtech/Midnite solar offer a breaker with a 50,000 amp interrupt rating. Midnite only carries them up to 250 amps, you might be able to find them from another reseller at 400 amps.

What inverter are you running that runs at 400 amps?

I am running a schneider conect XW +

Schneider recommend a minimum battery off 400a

Question?? are we aloud to link relevant YouTube videos about this topic ???

Urge38 · May 30, 2023

mikefitz said:
Perhaps the inverter data was referring to the AC fuse interrupt rating.

Since the usual 20kA rating is at 130v or higher, I would expect the current would be higher at lower voltages.

Short current of battery pack

the manufactures goes on to list fuses and there reference numbers. (only I can not find them here in the UK)

they are indeed 50ka and 100ka in DC (if I am correct)

I was watching a video of some guy shorting out small 5amp cells and measuring the voltage,
it makes you wonder what the short circuit voltage could be for my four rack batteries combined !!!

SeaGal · May 30, 2023

Urge38 said:
it makes you wonder what the short circuit voltage could be for my four rack batteries combined !!!

Short circuit voltage should be zero, by definition!

400bird · May 30, 2023

Urge38 said:
I am running a schneider conect XW +

Schneider recommend a minimum battery off 400a

That is 400Ah (amp hours of capacity)
They recommend a 250 amp breaker/fuse.

Urge38 said:
Question?? are we aloud to link relevant YouTube videos about this topic ???

Yes!

Urge38 · May 30, 2023

400bird said:
That is 400Ah (amp hours of capacity)
They recommend a 250 amp breaker/fuse.

Yes!

Urge38 · May 30, 2023

Urge38 · May 30, 2023

am I reading the schneider Manuel wrong???

I read it as to say, it needs a 400a current limiting fuse AS WELL AS a 250a breaker

400bird · May 30, 2023

I believe the paragraph above the charts is explaining the reason for the difference in ratings between a fuse and breaker. They are concerned you'll pop a 250 amp fuse with inrush currents. The expectation is that the breaker is slower to respond.

I have an XW Pro 6848 (North American split phase version, but otherwise basically the same inverter) I don't remember seeing that same chart, but it is likely present in both.
If you purchase a power distribution panel from Schneider, it will include a 250 amp battery breaker, no fuse.

yabert · May 30, 2023

Urge38 said:
Most if not all, Class t rated fuses I've seen have a interrupt capacity of 20,000A DC for my 400A rated fuse. Littelfuse JLLN 400A or Bussman JJN 400

ONLY the manufacture of my inverter states a 50Ka or 100Ka interrupt rating.

Look a this: https://diysolarforum.com/threads/eaton-amx-and-amh-fuses-alternative-to-class-t.60804/

mikefitz · May 30, 2023

Urge 38, since you are in the UK consider the equivalent to class T, a HRC fuse. Look online at the major distributors, like Farnell.

https://uk.farnell.com/c/circuit-protection/fuses-fuse-accessories/fuses/hrc-fuses

Or CEF, example,

200A CTFP HRC Fuse (Sold in 1's)

BS industrial fuse links with bolted connections to IEC 60269-2, BS 88-2

www.cef.co.uk

HRC fuse above, at 250v DC, withstand 40kA

Mike

Urge38 · May 31, 2023

mikefitz said:
Urge 38, since you are in the UK consider the equivalent to class T, a HRC fuse. Look online at the major distributors, like Farnell.

https://uk.farnell.com/c/circuit-protection/fuses-fuse-accessories/fuses/hrc-fuses

Or CEF, example,

200A CTFP HRC Fuse (Sold in 1's)

BS industrial fuse links with bolted connections to IEC 60269-2, BS 88-2

www.cef.co.uk

HRC fuse above, at 250v DC, withstand 40kA

Mike

Hi Mike

thats interesting,

I thought I had to go class T

so I am guessing from your reply, that HRC is equivalent to class T ??

would be good to clear that up for myself or any other Uk forum user

I will look into this

Thanks every one

Supervstech · May 31, 2023

Urge38 said:
I am running a schneider conect XW +

Schneider recommend a minimum battery off 400a

Question?? are we aloud to link relevant YouTube videos about this topic ???

Linking videos should be fine.

Urge38 · May 31, 2023

yabert said:
Look a this: https://diysolarforum.com/threads/eaton-amx-and-amh-fuses-alternative-to-class-t.60804/

View attachment 151156

VERY VERY HELPFULL and interesting read,

many kind thanks

Urge38 · May 31, 2023

Supervstech said:
Linking videos should be fine.

Still stuck on a fuse !!!!

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