inverter fuse/breaker

[starcraft69]

I am purchasing a 3000 watt inverter and wondering should i use a ANL 300amp fuse or a 300amp breaker between batteries and inverter?

[time2roll]

I would call 4/0 minimum, may need 250MCM if you expect full performance including the surge. Also may depend on length.

1/0 is more for 1500/1800 watt inverter.

Or is this one of those cheapos that really only produce 50% to 70% of rating?

Class T will pass 2x current for some time before it opens. A bit of a slow-blow fuse so I would keep it a bit tight.


Note 2x rating takes a full minute to open.

I would go 200 max class-T or 250 ANL on 1/0 wire.

Custom cables made here up to 4/0:
http://www.genuinedealz.com/custom-cables

[starcraft69]

MrWizard wrote:
No I don't think it's going to handle 8000 amps short
Why should it
You want it to trip at 300

What do you think will a 300a breaker work and be safe with 1/0 cable ?

[starcraft69]

DrewE wrote:

starcraft69 wrote:

This is what i was thinking Is 300amp breaker the right size?

What size wire will you be using? That's the main purpose of the fuse--to prevent a fire from the wire overheating in the event of a short circuit.

300A is a reasonable ballpark value, though larger might be better as most inverters have a surge capability somewhat beyond their nominal rated capacity. (Well, decent inverters do; all bets are off for questionable unknown brand inverters from overseas.)

Edit: The inverter instructions may have some recommendations on power lead wire size and fusing.

I am planning on using 1/0 wire

[BFL13]

The owner's manual for my Vector SST MSW inverter says to use ANL fuses for all wattage inverters in that class. Some not too clear wording that the ANL fuse "goes with" the surge rating of the inverter for when it will blow.

Specification table says for a 3000w(6000 surge) to use a 500a ANL fuse. Wire should be 2/0 for up to 6ft and 250mm for up to 10ft

With my 2000w that says use the same 500a ANL fuse, I used their "kit" wiring of two -three ft #4 instead of a single 1/0 at pos and neg (has two of each) so my choice at the pos battery post was:

A. put a 500 ANL fuse to the post with the two #4s to that fuse, or
B. put a 250 ANL fuse on each wire to the post (what I did)

[TechWriter]

starcraft69 wrote:
I am purchasing a 3000 watt inverter and wondering should i use a ANL 300amp fuse or a 300amp breaker between batteries and inverter?

For my 2000W inverter/charger, I use this 300A magnetic-hydraulic DC breaker from BlueSea.

I used to use a fuse, but if they blow (and they do), then you had better carry spares.

[GordonThree]

MrWizard wrote:
No I don't think it's going to handle 8000 amps short
Why should it
You want it to trip at 300

I want it to be able to break an 8000 amp arc if something fails inside the inverter and Bat+ crowbars to ground.

The filling and design of a Class T insures this. An ANL doesnt... I don't know about circuit breakers, that's why I'm asking?

[GordonThree]

These big fuses have a name ... the catastrophic failure fuse

[MrWizard]

No I don't think it's going to handle 8000 amps short
Why should it
You want it to trip at 300

[pianotuna]

Fuse with class T to the rating of the wire.

[DrewE]

starcraft69 wrote:

This is what i was thinking Is 300amp breaker the right size?

What size wire will you be using? That's the main purpose of the fuse--to prevent a fire from the wire overheating in the event of a short circuit.

300A is a reasonable ballpark value, though larger might be better as most inverters have a surge capability somewhat beyond their nominal rated capacity. (Well, decent inverters do; all bets are off for questionable unknown brand inverters from overseas.)

Edit: The inverter instructions may have some recommendations on power lead wire size and fusing.

[GordonThree]

What's the DC current interrupt rating of this 300 amp breaker? Can it handle the direct short capacity of your battery bank? Example: my bank is rated at 8000 amps direct short

[starcraft69]

KD4UPL wrote:
I wouldn't use the ANL, the Class T is the fuse you want. But, I would prefer a breaker. It will act as a disconnect switch if you need to shut off power to the inverter for some reason. And, if it every trips, you can reset it instead of having to find/order and install a new fuse.
Blue Sea, Outback, and Midnite solar (as well as others I'm sure) will have the breaker you need.

This is what i was thinking Is 300amp breaker the right size?

[KD4UPL]

I wouldn't use the ANL, the Class T is the fuse you want. But, I would prefer a breaker. It will act as a disconnect switch if you need to shut off power to the inverter for some reason. And, if it every trips, you can reset it instead of having to find/order and install a new fuse.
Blue Sea, Outback, and Midnite solar (as well as others I'm sure) will have the breaker you need.

[GordonThree]

Neither ... at that amperage, go with a Class T fuse

for background, read about interrupt rating and direct short rating on batteries.

[2oldman]

Fuse. I guess I could look it up, but I didn't know DC used breakers.