Single vs. Multiple Class-T Fuses

[Shimmy]

Anybody see this as a bad thing?

Other than the fact that they are single pole and you should be using 2-pole for PV? I'm not 100% sure the enclosures work when the breakers have the bus tie between poles installed. You might be short on space.

The second ones look better to me, as long as you are under the 110VDC limit.

 

[Lt.Dan]

Other than the fact that they are single pole and you should be using 2-pole for PV? I'm not 100% sure the enclosures work when the breakers have the bus tie between poles installed.

Not using it for PV. Using it for batteries.

Sig Solar already sells the 2 poles tied together. Look at the link posted. They do it becasue the breaker is only 100a, so tieing them together gives 200a of interruptible current.

You might be short on space.

I need to find out the size of enclosure I will need for sure.

EDIT: Looks like Sig Solar even sells a dual pole breaker in an enclosure, and they have a picture of the inside. Plenty of space. Too bad I need 3x.

Nader DC Circuit Breaker | 60V 200Amp with Enclosure

Signature Solar provides solar panels, off-grid solar systems, grid-tie, and hybrid systems. Quality solar inverters, bifacial solar panels, complete solar kits, solar batteries. Featuring brands such as EG4 Electronics with their solar battery, LifePower4 and EG4 LLifePower4 and EG4 LL

signaturesolar.com

 

[Tulex]

I ended up going with a Dihool 200 amp. Not cheap, but I liked it being a single unit.

https://www.amazon.com/dp/B09P4SLPPJ?psc=1&ref=ppx_yo2ov_dt_b_product_details

They make a 300 amp

https://www.amazon.com/DIHOOL-Circuit-Off-Grid-Disconnect-Inverter/dp/B09P4SHSML/ref=sr_1_23?crid=1Q8T2CLOXH7FW&keywords=dihool&qid=1682479091&sprefix=dihool%2Caps%2C621&sr=8-23&ufe=app_do%3Aamzn1.fos.18ed3cb5-28d5-4975-8bc7-93deae8f9840

 

[Shimmy]

I ended up going with a Dihool 200 amp. Not cheap, but I liked it being a single unit.

https://www.amazon.com/dp/B09P4SLPPJ?psc=1&ref=ppx_yo2ov_dt_b_product_details

They make a 300 amp

https://www.amazon.com/DIHOOL-Circuit-Off-Grid-Disconnect-Inverter/dp/B09P4SHSML/ref=sr_1_23?crid=1Q8T2CLOXH7FW&keywords=dihool&qid=1682479091&sprefix=dihool%2Caps%2C621&sr=8-23&ufe=app_do%3Aamzn1.fos.18ed3cb5-28d5-4975-8bc7-93deae8f9840

Do you realize that unit requires an inline fuse to break a fault at 48VDC?

 

[Tulex]

Do you realize that unit requires an inline fuse to break a fault at 48VDC?

I didn't read it that way, but instead, that it didn't provide for the lower voltage.
So, I emailed them, they said just that, their reply below, I don't know if it pans out.

Calculation formula for short-circuit current
Isc=V/R
V= Voltage
R=resistance (Resistance needs to be calculated based on your equipment and cables)
The smaller the voltage, the smaller the short-circuit current, and the 12V-30V battery cannot reach the breaking current due to short-circuit
48V
Isc=48/(0.1~1)

So I asked, "So are you saying that it doesn't have short circuit protection at 12-30V, but it does above 30V?"
and they replied:
Yes, when the resistance is relatively small, 48V/0.1(resistance) 480A＞300A So it can be protected

 

[rhino]

There was discussion about that brand/breaker here: https://diysolarforum.com/threads/dihool-breakers-amazon.53147/

 

[Lt.Dan]

I still see it as them recommending a fuse with voltage greater than 30v.

 

[Lt.Dan]

I purchased 3x of these yesterday:
Amazon Breaker
and this enclosed:
DIN Rail Enclosure

The breakers are pretty cheap, but I'm more so looking to use them as a switch for disconnecting an individual pack, not to interrupt current. From my 3 batteries, I can only pull 60a from each one any ways. We'll see how it works.

 

[rhino]

I'm just a bit weary of using something like that without a data sheet. Here is part of data sheet for a Noark MCCB for instance:

 

[Tulex]

To be honest, I'd prefer to go with a class T fuse and disconnect, but I haven't found a 60V disconnect I like.
Did find a 300A fuse with block for $41 on Amazon, which is the lowest I've seen.

https://www.amazon.com/dp/B0BZ875G7Q/ref=sspa_dk_detail_2?psc=1&pd_rd_i=B0BZ875G7Q&pd_rd_w=UGVwL&content-id=amzn1.sym.f734d1a2-0bf9-4a26-ad34-2e1b969a5a75&pf_rd_p=f734d1a2-0bf9-4a26-ad34-2e1b969a5a75&pf_rd_r=ZPN90YJPH11ZYS4GS5R7&pd_rd_wg=m72oQ&pd_rd_r=2b5fd8ce-cc61-4c38-9fcd-4b45102a8480&s=industrial&sp_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWw

 

[rhino]

Did find a 300A fuse with block for $41 on Amazon, which is the lowest I've seen.

I personally would never buy something like that off of Amazon from an unknown seller with poor ratings and no name product especially when you are relying on that product as a critical safety device.

 

[Robbert]

I personally would never buy something like that off of Amazon from an unknown seller with poor ratings and no name product especially when you are relying on that product as a critical safety device.

I have these and after installing, I started to doubt their quality. So I bought the Blue Sea fuse holders and separate fuses.

If you compare them it's a huge difference. I'll go for the heavier, slightly more expensive Blue Sea holders in combination with separate fuses.

 

[Shimmy]

I didn't read it that way, but instead, that it didn't provide for the lower voltage.
So, I emailed them, they said just that, their reply below, I don't know if it pans out.

Calculation formula for short-circuit current
Isc=V/R
V= Voltage
R=resistance (Resistance needs to be calculated based on your equipment and cables)
The smaller the voltage, the smaller the short-circuit current, and the 12V-30V battery cannot reach the breaking current due to short-circuit
48V
Isc=48/(0.1~1)

So I asked, "So are you saying that it doesn't have short circuit protection at 12-30V, but it does above 30V?"
and they replied:
Yes, when the resistance is relatively small, 48V/0.1(resistance) 480A＞300A So it can be protected

Their response is grossly incorrect. The issue isn't the short circuit current, it is the arcing at a higher voltage. Circuit Breakers have a maximum breaking current at a given voltage; that is linked to their ability to clear the arc. This is a common situation in both DC and AC systems, although the mechanics are a little different.

 

[Tulex]

I personally would never buy something like that off of Amazon from an unknown seller with poor ratings and no name product especially when you are relying on that product as a critical safety device.

You can find that same fuse and holder for much more many other places.
I buy a lot of stuff from Amazon. I can't tell you how many items I've found that are the same exact item with different names/sellers. I bought a jackhammer that was half the price of the top selling jackhammer. EXACT same jackhammer. There were over 10 different brands of that same exact jackhammer. Go to Alibaba, you can order most anything with your logo on it. Yeah, it's about safety. Doesn't mean you always have to spend more. In fact, that mentality is part of what keeps top brand pricing so high.

 

[Tulex]

Their response is grossly incorrect. The issue isn't the short circuit current, it is the arcing at a higher voltage. Circuit Breakers have a maximum breaking current at a given voltage; that is linked to their ability to clear the arc. This is a common situation in both DC and AC systems, although the mechanics are a little different.

I didn't have confidence in their reply, but mostly because I don't know that side of electric. Either way, They are being returned, going with the fuse and disconnect.

 

[rhino]

You can find that same fuse and holder for much more many other places.
I buy a lot of stuff from Amazon. I can't tell you how many items I've found that are the same exact item with different names/sellers. I bought a jackhammer that was half the price of the top selling jackhammer. EXACT same jackhammer. There were over 10 different brands of that same exact jackhammer. Go to Alibaba, you can order most anything with your logo on it. Yeah, it's about safety. Doesn't mean you always have to spend more. In fact, that mentality is part of what keeps top brand pricing so high.

Sorry but in this case that fuse holder looks nothing like the "top brand" fuse holders and is designed fundamentally cheaper so it isn't simply a matter of paying less for a "no name" brand of same quality. There is an issue of stock availability of these however.

 

[rhino]

You can get even higher quality Blue Sea one that @Robbert mentioned directly from Home Depot and is in stock.. it is $30 more than that Amazon one but is far superior in build and quality: https://www.homedepot.com/p/Blue-Se...-With-Insulating-Cover-200A-5007100/316304155

 

[Tulex]

Sorry but in this case that fuse holder looks nothing like the "top brand" fuse holders and is designed fundamentally cheaper so it isn't simply a matter of paying less for a "no name" brand of same quality. There is an issue of stock availability of these however.
View attachment 146801

I didn't say it looked like it, simply that it doesn't have to. Pretty sure you could bolt the lugs right to the fuse and cover it with shrink tube and have as secure a connection as needed. No I'm not recommending that. My point is that I don't think you need 1/4"-1/2"buss bar for bolts less than an inch apart. But to each their own.

 

[rhino]

Pretty sure you could bolt the lugs right to the fuse and cover it with shrink tube and have as secure a connection as needed.

I'm thinking more of long term maintainability. If the fuse goes that is going to be an ordeal to replace it especially if it isn't you that has to replace it.

My point is that I don't think you need 1/4"-1/2"buss bar for bolts less than an inch apart.

This is again for safety and maintainability. If the fuse goes you won't have a loose live cable floating around since it will always be attached to a bolt and never have to remove it.

 

[Tulex]

So, after just reading a Post about a 300 amp fuse melting the plastic of the holder ( not T class ), I am definitely ready to eat crow and admit many of you know more than me. I would have put a nut between the plastic and fuse, but still, why play games. As usual, it pays to listen to the experienced. Between your advise and the poster's experience, the cheap fuses are being returned. Thanks