Solar PV advice

[Richard77]

The fuse current capacity needs to be rated in relation to the current capacity of the cable .

I see...

So it wouldn't be wise to have 2x 35mm² that are rated for 240A with a fuse that is rated 400A even though it would only use less than 200A (battery max discharge/charge is 200A and inverter is max charge/discharge 190A).

It would be good practice to spec the cables to be capable of carrying 400A just in case, so 70mm² (485A)?

[Stinsy]

The fuse current capacity needs to be rated in relation to the current capacity of the cable .

I see...

So it wouldn't be wise to have 2x 35mm² that are rated for 240A with a fuse that is rated 400A even though it would only use less than 200A (battery max discharge/charge is 200A and inverter is max charge/discharge 190A).

It would be good practice to spec the cables to be capable of carrying 400A just in case, so 70mm² (485A)?

If you have cables rated at 240A then you need a fuse rated at 240A or lower.

[Richard77]

The fuse current capacity needs to be rated in relation to the current capacity of the cable .

I see...

So it wouldn't be wise to have 2x 35mm² that are rated for 240A with a fuse that is rated 400A even though it would only use less than 200A (battery max discharge/charge is 200A and inverter is max charge/discharge 190A).

It would be good practice to spec the cables to be capable of carrying 400A just in case, so 70mm² (485A)?

If you have cables rated at 240A then you need a fuse rated at 240A or lower.

Ah I see... Thanks.

I was thinking I needed 250A fuses... So I really should go with 200A fuses then if using 35mm² (240A) cable and battery/inverter max 200A/190A respectively?

[Stinsy]

I see...

So it wouldn't be wise to have 2x 35mm² that are rated for 240A with a fuse that is rated 400A even though it would only use less than 200A (battery max discharge/charge is 200A and inverter is max charge/discharge 190A).

It would be good practice to spec the cables to be capable of carrying 400A just in case, so 70mm² (485A)?

If you have cables rated at 240A then you need a fuse rated at 240A or lower.

Ah I see... Thanks.

I was thinking I needed 250A fuses... So I really should go with 200A fuses then if using 35mm² (240A) cable and battery/inverter max 200A/190A respectively?

200A fuses seem sensible in this situation. Remember they don’t “blow” at 201A. They’re rated for 5mins at 2x rated capacity and 4s at 5x.

[Richard77]

What the #*@£ ..... The size of thing and the fuses!



I've seen smaller ones in the old black and white Frankenstein films

[Moxi]

were they smaller or just further away

Back to reality though that's about the size of mine and the fuse links - always make sure you have the switch fully closed as it takes some force to push the links home fully, if not its possible to get localised heating and melting of the plastic case.

Moxi

[Richard77]

were they smaller or just further away

Back to reality though that's about the size of mine and the fuse links - always make sure you have the switch fully closed as it takes some force to push the links home fully, if not its possible to get localised heating and melting of the plastic case.

Moxi

I'm about Dougal's level hehe

Going to be a few weeks before it's getting installed... Need to finish the garage first and waiting for garage doors.

Also... Back fences blew down today and snapped all the posts so going to need to sort that too!

2026 for the big switch on

[Stinsy]

What the #*@£ ..... The size of thing and the fuses!



I've seen smaller ones in the old black and white Frankenstein films

Breaking DC is no joke!

You see why we call them "Frankenstein Switches"!

[Andy]

I have some settings coded on my victron cerbo such that I can control the DC currents. They are reduced to zero so I can safely pull the breakers. Making the breakers without precharging the capacitors also makes a nice bit of molten metal.

Same goes for the eltek. To increase the life of the relays, current is reduced to zero before operation.