What size fuse

Fuse as close to the battery bank as humanly possible. Fuse to the wire size. Use big wire with the shortest possible run to the inverter.

Differ manufacturers advise different specifications. I have an inverter that starts making noise at 12.3 volts
Another starts at 11.5.
Low voltage can be a real issue. Wire size should be as specified and not on a calculated or theoritical load. I would not install anything less then a multi-stranded #2 and no building wire. Use marine or stereo wire.

G. Or do you go by the instruction manual.

My cheaper PSW inverter (Canadian tire brand) seems to be hypersensitive to low voltage. I originally wired it with 2 AWG welding wire but recently re-wired it with 2/0. I used a 125amp circuit breaker, I like to use a circuit breaker so that it can be used as a switch as well. The 2/0 seemed to solve the low voltage issue but if I would have realized how difficult that wire is to deal with I may not have went that large.

tarnold wrote:
Op again. The unit ships with "2 feet 7 awg " (I know!) I plan on running about 6' #4.

I installed my 1000 watt PSW inverter in the front pass through storage compartment so it took 6' of 4 gauge cable to reach the battery. I never draw more than 70 amps and used an 80 amp fuse. Pics are in my gallery starting here.

These fuse questions are nearly all the same.
A. Do you wire the inverter for what it is rated for including surge? or just what it is rated for continuous?
B. Do you wire the inverter only for as much load as you will ever be running?
C. You do fuse for the wire you did actually use, whatever you chose for wire.
D. The fuse must go near the battery positive post--some rules say "within 18". What if the inverter-battery wire is only 18" long?--no fuse and let the wire be the fuse?
E. Slow blow vs fast blow fuse--you want a slow blow so short surges won't blow it---so then back to A.--do you fuse for surge if it will only be so short your slow blow fuse won't blow anyway?
F. If the wire is all up front and visible so you can see if it is melting or at least turning a burnt sort of colour, do you even need a fuse, where you certainly would if the wire went through a wall out of sight-- and if it melted inside the wall.

Some inverter specs call for more of a fuse and fatter wire for the same size of inverter than others. Seems to turn on whether to wire and fuse for surge or not where surge is often twice the normal rating.

enblethen wrote:
1000 amp inverter doesn't tell me much.
Is 1000 continuous or surge?

Every inverter I've seen is rated in watts, and that's the max continuous rating. Surge is usually double that.

The standard catastrophe fuse will be hundreds of amps, but you can fuse it down to whatever works without nuisance blowing. I'm not sure why you'd put anything but a cat fuse on it.

kellertx5er wrote:

time2roll wrote:
Assuming #4 or #2 wire I would be about 125 to 150 amps.
If you are going smaller on the wire the fuse would need to be reduced.

Neither #4 (85A) or #2(115A) will safely carry 125 amps.
What does the mfg. recommend?

Ok I do assume quality marine wire with 105C insulation not bundled.

http://assets.bluesea.com/files/resources/instructions/9113.pdf

I assume your ampacity is bundled 60C building wire as romex or in conduit.

Doubt the OP will see more than 30 amps with the load described. Still I recommend a proper install to use full capacity because usage may change.

I like to use the BLUE SEA type fuse holders with cover so that all of my cables will use the ring type terminals...



Almost all of my battery wiring uses the ring terminals so it makes for good install practices to have all of my switches, terminal blocks, meters, etc all have the 5/16-inch lugs on them... Everything dresses up nice doing it this way...

I order all of my BLUE SEA PRODUCTS from AMAZON...

Roy Ken

1000 amp inverter doesn't tell me much.
Is 1000 continuous or surge?
Make and model would help!
Your light load, you could get by with your listed wire size of #4 or #2. Fuse for around 60 amp. You would not need an ANL fuse for that size.