15 amp fuse replace with a breaker

the original purpose of 12v plugs, was to get hot and light cigars or ciggarettes.

Too bad the 12v plugs now get nearly as hot passing more than 60 watts to modern devices,

The ciggy plug connector/receptacle, is a crime against DC electricity.

Peg Leg wrote:
An Arc Fault Breaker sounds like something required for explosive atmospheres.

My 10 year old house has 2 Arc Fault Breakers for the bedroom plugs. Not much to explode there. :B

Yea I hear ya. People have been giving me grief for plenty of years for my 2000w and 300w pair of inverters.
I know what works for me. BTW I still have a 100w MSW from the old days using the 12v connector.

The overhead on the Magnum is about 40% of the load. So instead of using say 5 amps I'd be using 10.

OK lets get an 80w inverter for the 12v outlet, proper 50a connection to wire in that 400w inverter, and some better labels on the fuses.

Besides why not just use the magnum?

The usual load is a laptop and a heating pad. Total less than 100 watts.

The outlet has a 15 amp fuse at the panel and nothing else is on the circuit. Because I've been running in this manner since 2009, I don't think overload is a serious problem.

The fuse did exactly as it is intended to do and blew immediately. Replacing it is down on my hands and knees using a flashlight to attempt to see which fuse has failed. There are labels but they are cryptic.

At least the maker used a decent size of wire, but the choice of location is definitely less than convenient.

If the inverter was loaded enough to pull more than the size of the fuse in amps, so it blew the fuse, you would not want an auto- resetting CB in there to keep popping and resetting.

A CB that did not auto-reset could work I suppose, but there is maybe a timing issue in how long it takes or how hot it has to get to pop compared with a fuse?

This is worse than I imagined....
I don't think a CB is the solution.

CA Traveler wrote:

pianotuna wrote:
My need is quite simple. I run a 400 watt inverter from a cigarette lighter plug (ya I know, I should not).

Let's see: 400W/12.7V = 31A. Really? Dam* right you should not!

Why not do it right?

EDIT--actually using the divide by 10 rule, that would be 40 amps.

If all he usually runs from the 400w inverter pulls less than 8 amps DC, then why not? IMO (not shared by some here it seems) it is the size of the load that counts, not what the inverter "could do" from its rating.

If PT puts too big a load in that inverter, then the 10 amp "TV Fuse" in his DC fuse panel that is for the Winegard 12v socket and antenna booster will blow. Which is what happened.

What's the big deal?

I do not think what you are planning is the correct way to go.
400 watt inverter would draw around 35 amps at 12 volts.
600 watt heater would draw around 5 amps at 120 and ten times that for 12 volts DC.
Installing a circuit breaker trying to protect your self from your self doesn't seem appropriate. No offense!