# Thread: Inverter Fuse?

1. ## Inverter Fuse?

Hello,

How do you calculate the size of fuse to place between an inverter and the battery?

I know that: I = P / V hence 58.3 = 700w / 12v

(700w being the size of my inverter)

Rounding up gives me 60A, so should I just put a 60A inline fuse between the battery and inverter power leads?

Thanks...

2. The in-line fuse is there to protect the wiring so that current beyond the rating of the wire won't go through it, causing it to heat up to the point of being a fire hazard.

As a general rule, a fuse that is somewhere bewteen the fuse that protects the equipment and the current rating of the wire that powers it will do the job. Personally, I would reconmmend a fuse rated closer to the rating of the fuse to protect the equipment.

Real-world example:
I helped install a Carnetx P1900 for someone recently. The Carnetix uses a 15A fuse. We used a 20A fuse on the power wire. So if there is more than 20A on the wire as a result of a short, the 15A will blow first, protecting the Carnetix. If there is still a short, then the 20A will blow, protecting the wire (and ultimately the rest of the vehicle).
Make sense?

3. [QUOTE=DarquePervert;1039425]
As a general rule, a fuse that is somewhere bewteen the fuse that protects the equipment and the current rating of the wire that powers it will do the job. Personally, I would reconmmend a fuse rated closer to the rating of the fuse to protect the equipment.
QUOTE]

I see, great explaination...

I only asked because I was aiming to connect my inverter to the battery via a fused distro block, protecting the wiring and equipment (inverter) is a top priority for me.

If the max power to the inverter is only ever going to be 700w (size of my inverter) then a 60A (700w / 12v) fuse should be fine????

I wouldnt want anything more going to the inverter than 60 Amps Right?

4. You're way off.

I'd say probably a 25A or 30A fuse would be appropriate, actually. I have a 400w inverter and ithas a 20A fuse.

It's also dependent on the size of the power wire. The fuse in your distro block is to protect the individual power wire going to the inverter.
Does the inverter have an on-board fuse?
Also, does the manual for the inverter say anything about fuse rating?

5. Originally Posted by DarquePervert
Does the inverter have an on-board fuse?
Also, does the manual for the inverter say anything about fuse rating?
Ok, I opened the inverter up and I can see two 40A blade fuses. However I dont know if this means its fused at 80A or 40A with one being a backup???

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