Burnt wire on my univolt

[MonaxLisa]

The top wire (purple, bathroom lights and water pump) is burnt on the end. I'm going to have someone take a look at it but I'm not sure that they'll know what to do. I took the univolt off the wall and it does to a wizard thing (that deals with the charge from the battery) that is behind the bathtub and the purple wire goes into a bundle. I hate the though of someone taking apart that bundle, who know's what will go wrong.
Does anyone have any feedback on how to go about figuring out how to figure out what's wrong? Also, if I need to replace the whole thing what does it get replaced with? Will the wire hookups be the same?
The wire is burnt and that fuse gets super hot and then of course burns out. I'm hoping that if the wire is cut (the burnt section removed) and then maybe it will be ok but it seems like there must be a short somewhere...what a bummer! Thanks for any input

[Condoluminum]

You do have a short for sure... (the easy part..)

Finding it can be a serious pain... Much of he wiring is hard to trace, working between the double walls or behind/below cabinetry... If you have an owner manual, that can help with general locations, though of a PO (prior owner, bless their hearts..) rewired some of the wiring, then you are likely to need original detecive work..

As for original Univolts, they tend to be noisy at night and may overcharge battery if left pluged in for extended periods.. The newer 3 stage floating charger/converters offer a better way to protect your batteries... (search on "3 stage converter")

[azflycaster]

The problem could be caused by a bad connection at the fuse panel. Make sure you have the proper size fuse (20 amp) installed in the panel and the contacts are tight and clean. Also make sure the wire connection is clean and tight. You may need to spice in a small amount of wire to replace the piece that has burnt. I would use the same gauge wire, solder it together and cover the splice with shrink tubing.

[MonaxLisa]

definitely the right size fuse, I have newer wizard thing in behind the bathtub with a remote pendant so something's been updated i'm just not sure what. My owners manual is no help with wiring!! It shows the univolt, but not where any of the wires go! Strange! I am hoping that cutting off the burnt end and cleaning the thing it goes in to will solve it, but that seems too simple, I'm sure it will be much more complicated :/
Oh, and this univolt makes no noise (odd?)

[azflycaster]

If you have a charge wizard, your univolt has been replaced with a Intelipower converter. I have a 9245 in my trailer and could not be more pleased with it. The power from your converter attaches to the distribution board that you attached a photo to on the rear of the board. It then goes to each of the fused circuits on the board. The chances of a problem with the converter are very slim. IMO. If you had a dead short the fuse would blow immediately and not cause the wire to heat up.

[TG Twinkie]

I agree with the bad connection senerio. If you can; cut the wire back strip it, make sure it is not corroded. Clean up the connection point; install the wire into the connection point and tighten securely. If you continue to blow the fuse, you would need to check individual devices in the circuit (ie pump and so on) to see which one causes the fuse to blow.
Is the fuse actually blown apart where you can see it thru the glass. If not the heat from the bad connection can cause the element inside the fuse to become detached from the end cap of the fuse. Also make sure the fuse is tight in the holder at each end, the excess heat can cause the "clamp" to lose it's spring tension.
I don't believe there is any problem with the converter.

[Aage]

My '74 Sov, still with the original actual Univolt ("You'll love the way it hums!") has the EXACT same problem.

The purple wire feeds all lights in the rear bath and mid sleeping area (too much draw, IMHO), and the end of it had black, crumbling insulation from being overheated.

I cleaned the terminals on the Univolt, which were corroded, and noted that the purple wire's fastening screw had been fairly loose. I trimmed an inch or so off of the purple wire and re-connected it, making sure that it was done up snugly.

It still heats up like crazy. The fuseholder clips are not very tight either. If I jiggled the fuse, the lights would sometimes come on.

I had convinced myself that the Univolt and its lousy fuse panel were the source of my problem, and have a new Iota 55A unit to install this spring.

But this thread has me wondering...

MonaxLisa:

Question for you: do you have a battery installed in your TT? I don't and am wondering if that could have any impact on the problem.

[MonaxLisa]

I'm going to try cutting the wire etc and seeing what happens. The fuse holder was a little loose but it squeezed back together so it's tight (is that ok?) also, what should I clean that little hole that the wire goes into with, anyone know? I'm guessing that the screw (screw looking thing) should be tight to hold the wire in place but I don't know if the wire should be touching the end of the fuse or not. If I look at the other wires two are nearly touching the fuse and one isnt.

Richard- thanks for the diagram, but it doesn't show where those wires go, it only
says that the wire I'm having problems with is circuit one.

TG- the fuse melts, either in the center of the little metal thing inside, or at the very end and a little bubble of melted metal will come out of the end cap. ....so that sounds like it is the heat any not something blowing the fuse? Maybe that's a good thing!

Aage- TT? There is an RV battery in the trailer, it seems to hold it's charge really well. I just leave the fuse out of this one holder that's giving me the problem. It hasn't been a big problem up until now, we're boondocking and I've got a full water tank and no water pump!

[Excella CM]

If the switches for the pump and the bathroom lights are "off" then there should be no current draw at the fuse and it should not draw a spark when you put the fuse in. If there is current flowing, then you have a short.

High resistance caused by loose connections generates heat in proportion to the current. Make sure fuse holders and terminals are clean and tight. If a fuse holder has been over-heated it may lose its temper and no longer grip the fuse tight enough (compare with another holder), in which case you will need to replace it or bypass it with an in-line fuse.

[MonaxLisa]

Excella- I never thought of checking the fuse while all of the switches are off, thanks!! Also never thought of an in-line fuse!

[Aage]

Mona,

TT = travel trailer
AS = Airstream
moho = motor home

those three abbreviations are probably the most commonly used ones on here, but there are others.

OK, thanks fo letting me know you have a good battery, I'm still looking to confirm what exactly is my own problem. I'm hoping it isn't a short hidden behind one of the ceiling or wall panels.

To Excella's point, I think he's on the right track. Your fuse panel was the one that was fastened to and part of the original Univolt, so despite a PO (previous owner) replacing the Univolt, they kept the fuse panel, and, like mine, it has lost its temper, and has built-in resistance, plus won't keep a tight grip on the fuse. All those things add to the resistance in the circuit, which translates to heat, and finally destruction.

You need a new fuse panel. That may sound complicated, but it really isn't. They are commonly available at the retailers you frequently hear mentioned on here. I bought this one, and plan on putting it in as part of the replacement of my Univolt this spring.

I would suggest that you put a new one in your TT too. Otherwise, you may later have problems with other circuits, too.

Good luck, and let us know what you do!

[MonaxLisa]

that fuse isnt sparking when all switches are off so thats good. I sprained my wrist so havent done any more with it. In the mean time my thermostat gave up the ghost..sheesh!!