Resolved Magnum inverter main fuse

[lostinfla]

Somehow, the main 350a fuse has blown on the inverter after I tried to "reset" systems by cutting shore power, turning off the engine battery switch and salesman switch. Does anyone know how/why this happened and what is the correct procedure for fuse replacement as I don't want to fry another fuse when installing it.

 

[Joe Hogan]

Wow, that is a big surge. In my opinion you should be sure there is not a dead short somewhere in your system before you install a new fuse. The power needed to fail this 350A fuse can damage all sorts of things.

 

[Chuggs]

More than likely a loose connection. Check connection points... two nuts and washer hold the 350A T-Fuse on. Make sure Negative is always connected to the inverter before adding the positive on Magnum systems with peripheral devices.

 

[lostinfla]

I actually connected the two wires together to make sure the system was ok, and everything powered up correctly, so I would assume there's not a short circuit anywhere. When connecting the wires, I got a small spark, but no where near what 350 amps would indicate. These are extremely sensitive quick blow fuses, but I can't see any reason this one went. Doing a search, I've seen others come up with the same problem (low battery indication, no charge on the panel) which led me to find the blown fuse. They just replaced the fuse and all was well. I just don't want to toast a 100.00 fuse.

 

[Chuggs]

Blue Sea Systems 5120 FUSE A3T (CLASS T) 350-AMP Amazon.com

 

[lostinfla]

Blue Sea Systems 5120 FUSE A3T (CLASS T) 350-AMP Amazon.com

Thanks Chuggs!

 

[lostinfla]

Ok, I think I figured out what went wrong. I removed the fuse before cutting the 110 feed to the inverter which may have caused the fuse to blow. I installed a new fuse and powered up the coach and everything is working fine EXCEPT... I have no power on the kitchen slide to the receptacles. The microwave works as does the telivator, but no go on the wall outlets. I have both legs of shore power coming in. Before I dig into the wiring, I figured I'd ask here to see if there's any hidden GFI's other than the three in the mid bath and one in the peg board bin. One in the mid bath was tripped, but didn't change anything on the slide. The GFI in the peg board bin has no power also. If anyone can add any info as to the slide wiring and where the feed comes from, it would be much appreciated!

 

[NWIP]

We have one GFI under the cabinet above the sink

 

[lostinfla]

We have one GFI under the cabinet above the sink

Thanks Bill, no power there either

 

[Neal]

Sounds like you blew the GFI breaker and it needs to be reset on the outlet with the reset button.

 

[lostinfla]

Sounds like you blew the GFI breaker and it needs to be reset on the outlet with the reset button.

Out of the 5 that I've found, two will not reset. I'll dig into it more tomorrow. Maybe missing a neutral somewhere. It sure does sound like a GFI somewhere though. Maybe one is bad.

 

[stang37]

I had a similar issue at my house. GFI tripped and would not reset. Turns out there was an electrical spike from the power company. It didn't affect all GFI just the ones on the leg that spiked. There was internal damage to all of them. Several had items plugged into them which didn't sustain any damage. All the GFI's had to be replaced.

 

[J&JD]

On my 17 I’ve had to replace 3 of the factory installed gfi’s that would not reset. They were simply faulty units for some reason. All three have been in place for several years now with no problems.

 

[redbaron]

I had to do the same on my 2019. I went with traditional house installs instead of the RVIA crimp style. When replacing one outlet, I saw where the wire was not pressed in firmly and could create a spark or loss of connection. My guess is this is your issue.

 

[Neal]

I read recently somewhere that Newmar acknowledged faulty GFCI outlets and they were replacing them under warranty. Probably recent years but we've heard plenty about GFCI outlet failures that I'd lean towards replacing them.

 

[lostinfla]

I'm going to replace the outside one with a standard outlet. At the eye Dr now getting dilated so I'm out of commission for a while. I'll report back when I find the problem

 

[Neal]

Something to consider though, when you're able to read again, is that they have worked this long and you can't discount there is a reason they are tripped.

 

[lostinfla]

Something to consider though, when you're able to read again, is that they have worked this long and you can't discount there is a reason they are tripped.

Since everything was working fine till I decided to power down the coach, I don't think there's a major problem. Now, since I've replaced the main fuse to the inverter, everything is back up to normal except the slide power which I'm convinced is due to a GFI issue. I believe whatever I did in incorrect sequence blew the main fuse and took out the GFI's.

 

[lostinfla]

Half blindly poking around, I did find there was power coming to the GFI's, got both of them to reset and all is well once again. I plan on replacing both though before our next trip. Thanks for all the help and suggestions!