Wires and fuses

[Begginer7]

Hi, I am installing a 12V system for a small shed with one 410W panel, a 1000W giandel inverter, one 12v 100ah SOK lifepo4 battery with a SOK shunt battery monitor and a 40A epever Scc, I have seen Wills video (DIY 400 Watt) and read his book but I still have some doubts.

1.- Since I dont have 12V appliances I am not installing the fuse block, in addition to the battery bolt one do I still need 2 circuit breakers or I just need the one for the Scc?

2.- For the 40A Scc I am planning a 50A circuit breaker, can I use something like this?:



As this type dont seems to be able to work with a 4 gauge wire probably I have to use a different one, what is the technical name for a circuit breaker that could handle that?

3.- For the battery I am planning a 100A fuse, it seems that the recomended one is a class t fuse, I found one online but it says voltage type is AC: can I use it?


4.- The wire sizes I will need are: from pv panel to scc 6mm, from battery to inverter 5.1 mm, from scc to circuit breaker 4.1mm, am I on the right track?
5.- I could place the Inverter and scc at almost floor level or put it about 1.5 from the floor to be able to read the Scc screen easier, which one is better?
6.- Are there any European providers for wires, connectors and fuses?

Please excuse me for the long post.

Thanks

 

[MisterSandals]

I found one online but it says voltage type is AC: can I use it?

No

For the battery I am planning a 100A fuse

Do you mean battery to inverter?
Assuming inverter has 10V cutoff…
1000W / 10V / .85 x 1.25 = 147A. (Use 150A fuse)

 

[MisterSandals]

The wire sizes I will need are: from pv panel to scc 6mm, from battery to inverter 5.1 mm, from scc to circuit breaker 4.1mm, am I on the right track?

You need to know amps, volts and wire length to determine which wire size.

 

[Begginer7]

No

Do you mean battery to inverter?
Assuming inverter has 10V cutoff…
1000W / 10V / .85 x 1.25 = 147A. (Use 150A fuse)

Thanks, I was thinking of the bolt fuse, actually the inverter has a 9.5V cutoff so it will take it to 155A so 160A fuse, the manual has this table:

 

[Begginer7]

For the 50A circuit breaker for the Scc could I use this one?

 

[MisterSandals]

For the 50A circuit breaker for the Scc could I use this one?

Those are dangerous junky ones. The breaker is a safety device. Look for a Bussman or Blue Sea systems.

Bussmann CB285-50 Surface-Mount Circuit Breakers, 50 Amps (1 per pack)
by Crimp Supply Inc
Learn more: https://www.amazon.com/dp/B01G5VETZY/

 

[Begginer7]

Those are dangerous junky ones. The breaker is a safety device. Look for a Bussman or Blue Sea systems.

Bussmann CB285-50 Surface-Mount Circuit Breakers, 50 Amps (1 per pack)
by Crimp Supply Inc
Learn more: https://www.amazon.com/dp/B01G5VETZY/

Thanks, found a list of European suppliers (https://www.eaton.com/us/en-us/prod...ses/electrical-iec-european-distributors.html) dropped a few emails maybe they sell retail.

 

[Begginer7]

No

Do you mean battery to inverter?
Assuming inverter has 10V cutoff…
1000W / 10V / .85 x 1.25 = 147A. (Use 150A fuse)

From this I gather that I need the 3, a bolt one for the battery positive, a main one before the inverter and the one for the scc, is this correct?

 

[MisterSandals]

Between solar panel and SCC, assuming your panel Imp is about 10A, you will want a 15A fuse and cutoff switch, or just a 15A breaker.

From 40A SCC to battery (or positive bus bar), 50A fuse.

From battery to inverter, 150A fuse. Many recommend class t fuse here. I have mine, just delivered but not installed yet. If you have a positive bus bar, put this between battery and bus bar.

Did I miss anything?

 

[12VoltInstalls]

For the 50A circuit breaker for the Scc could I use this one?View attachment 87963

Those are dangerous junky ones. The breaker is a safety device. Look for a Bussman or Blue Sea systems.

The breaker pictured has all the right words in the description- but because of the plethora of poorly designed but similar looking Chinese breakers of this appearance that are usually poor quality, the relatively small investment for the brand-name devices as suggested are what you want for a house, workshop, camper, or office. Your life is worth more than a few euros.
I’ve used those cheapies for winches, jeeps, etc but never for a camper, boat, or cabin. Quality brands get used for life-safety systems.

 

[Zil]

Use a quality Class-T fuse rated for DC for the battery positive. You could use a MRBF with a quality fuse. With LiFePo it is the interrupt capacity of the fuse that is important. Most breakers will not do.
Outside the USA I would take my custom to a Marine Supply Store.

 

[Begginer7]

Use a quality Class-T fuse rated for DC for the battery positive. You could use a MRBF with a quality fuse. With LiFePo it is the interrupt capacity of the fuse that is important. Most breakers will not do.
Outside the USA I would take my custom to a Marine Supply Store.

Thanks, I have contacted the local Marine supplies but I think they dont have what I need.

 

[Begginer7]

Thanks, I have contacted the local Marine supplies but I think they dont have what I need.

As I thought, they dont have what I need, do you have a specific MRBF in mind?

 

[Begginer7]

Between solar panel and SCC, assuming your panel Imp is about 10A, you will want a 15A fuse and cutoff switch, or just a 15A breaker.

From 40A SCC to battery (or positive bus bar), 50A fuse.

From battery to inverter, 150A fuse. Many recommend class t fuse here. I have mine, just delivered but not installed yet. If you have a positive bus bar, put this between battery and bus bar.

Did I miss anything?

I think not, however I cannot find the wires I would like, I bought a 35 mm2 (approx. Gauge 2) one for battery to inverter although I could use only one meter I got 2 meters each(+ -) just in case, from inverter to scc circuit breaker a 25mm2 (approx. Gauge 3) 20cm and from scc circuit breaker to scc a 16mm2 (approx. Gauge 5). This are somehow thicker than the recomended ones, is this affecting the fuses I should use?

I am using this table to transform Gauge to area:

 

[12VoltInstalls]

This are somehow thicker than the recomended ones, is this affecting the fuses I should use?

I overwire a lot of things that are big amp DC and close stuff like charge controller to batteries etc. There is no harm to this other than a little expense.

However, I fuse as if I were using the smaller “right sized” wire. Any event that will blow a fuse that is properly sized above the wire amp rating is probably catastrophic and I’d not want it to last long enough to “test” the oversized wire. Just blow and be done with it.

The fuse is to protect the wire, but when I oversize the wire I fuse for it to disconnect at the improper current of the smaller “correct-sized” wire.

 

[Begginer7]

Those are dangerous junky ones. The breaker is a safety device. Look for a Bussman or Blue Sea systems.

Bussmann CB285-50 Surface-Mount Circuit Breakers, 50 Amps (1 per pack)
by Crimp Supply Inc
Learn more: https://www.amazon.com/dp/B01G5VETZY/

After about a month of waiting it seems that Amazon will not ge able to deliver, locally I have 2 options, both are DC, MCBs one 33A and one 60A, they have to be connected to both negative and positive, which one shoul I install?

 

[Zil]

I disagree slightly. I fuse to the ampacity of the chosen wire. Or just slightly below if the exact fuse amperes is not available. I reduce voltage drop, to an anal fault.