Fuse bank melted

[Jared J]

Originally Posted by Byron Kinnaman

Somewhere near where the 120 cord comes into the trailer the "Green" wire form the 120 is attached to the frame and ground (round hole) on all 120 outlets. The converter may or may not have 120 outlet it's plugged into, it could be hard wired. If it hard wired there's a green wire on it that connected to the same green wire on 120 volt cord. The green wire on the converter is connected to all exposed metal, (required by law). The negative 12 volt at the converter is also connected to the exposed metal.

If you check with an ohm meter you'll find the 12 negative connected to the frame. Because the frame is exposed metal it's required that the frame is connected to the 120 Volt ground when plugged in. For clarification this ground is often called "safety ground". In the case of our trailers there is no other "ground". There's +12 or positive 12 Volts and - 12 or negative 12 Volts. There hot and neutral for 120 volt.

I checked my trailer, I have no 12v ground to my frame. I hooked the original 120v frame ground back up when I put the new converter in, so I know thats there.

[Thinh]

Originally Posted by glennco

Evening all,


Well the last couple times we used our scamp I found that the fuse to the battery in the fuse panel had blown. After it was blown none of my 12v lights or appliances would function. I finally had a chance to start investigating and found a melted fuse panel

Here's what I know so far:

1: the PO replaced the 'American' converter with a PD not purchased from scamp last year.

2: Last time I changed that 20amp fuse, I noticed the fuse block was moving a tiny amount on the board.

Questions:
The schematic shows an inline fuse off of the battery but so far I haven't found one. Can someone tell me where this inline fuse is on the scamp SD models?

The schematic appears to show that the 12v lights should function even if there are issues with the fuse panel, but with that 20v fuse on the panel blown, the 12 v lights don't function. Is that typical, or did someone mess with the wiring somewhere along the way?

Based on the fuse block failure, I'm believing I was an issue with the block itself. Anyone have other things I should check?

Please enjoy the photo I snapped of my melted fuse panel, and thanks so much for the help as always,

Paul

Here is my perception thru. your photo: There is servere short cct and the melting terminals suggest a possiible WRONG FUSE RATING in the supply's circuitry. If the colour code is applied correctly, the white wire is SO CLOSED to the black and if vibration is put into account, your panel housing looseness could possibly cause hazard. The paper of your fuse ratings seem to be printed out from a home computer-indicates a DIY project--->VERIFY FUSES' RATINGS for proper protection of circuitry. My last thought is...PLEASE DOUBLE CHECK YOUR SUPPLIES' WIRINGS AND THEIR'S FUSES' RATINGS( Battery, Converter, 110VAC)...

[glennco]

Great thoughts everyone thanks,


I've been thinking about this and there are a couple changes I'll likely make:

1: Add an in-line fuse to ensure we can't get back to the battery in the case of a short.
2: right now the power from the TV currently goes through the fuse panel as well. This seems overly complex to me, as we could easily have issues that the fuse panel would need to be in the middle of. I think I may move the power cable from the vehicle back to the factory position of being hooked to the battery + with a fuse.
3: It is a very interesting point raised above regarding fuse ratings for the board. That could definitely have been part of the issue.

I forgot to attach this pic last night, but in it you can see the state of the vehicle power connection to the trailer.

Thanks again, please continue with any thoughts you may have.

Paul

[glennco]

One more question,

Is it typical to run household solid core wire between between the converter and distribution panel on the DC side, or is this something a previous tech did when replacing the converter?

Thanks,
Paul

[Jared J]

I would use stranded, although insipid would work. One other thing I thought of, was to be sure you have quality fuses like littel/atc/etc. I usually grab a handful of fuses when I'm in a junkyard. Do not use harbor freight/etc. fuses. They have been proven to go way over their rating.

[Brian B-P]

Originally Posted by stevebaz

If you have trailer brakes and a breakaway switch you need a ground from the battery to the frame. Scamp ties the brake ground to the frame when hooked up to tow...
Without trailer brakes and a breakaway switch there would be no need to ground the battery to the frame if you ran a ground wire to each of your circuts.

Yes, and even with trailer brakes there would be no need to ground the battery to the frame if you ran a ground wire to the brakes. Scamp may not have done it, but you can.

You can still tie the battery negative to the frame, but there's no need to make that part of any circuit.

[Brian B-P]

Originally Posted by glennco

Is it typical to run household solid core wire between between the converter and distribution panel on the DC side, or is this something a previous tech did when replacing the converter?

No, it is not typical to run non-stranded wire, such as the cable built into houses for 120V AC service, for any low-voltage DC purpose.

<insert major debate about stranded wire here >

[glennco]

Yeah, solid vs stranded wire debate.


1 additional vote for stranded.

An additional question. Does scamp typically use 12awg wire for a power feed? Even fused at 20 amps, 10awg seems like it would be safer, or is that just overkill?

[steve dunham]

[QUOTE=lamimartin;406836]Hi Paul,
As you suspected, some bad contact or corrosion appear to have created conditions for a resistance that went hot or sparked and burned the fuse panel. Note that battery Inline fuse are often replaced by a auto reset breaker such as this one: so sparks on connecting the battery or very short power surge will not cut the main power.

I for one am not partial to resetting breakers for circuit overcurrent protection .I would install an inline fuse in the incoming DC line at the battery and at the converter . Fuses offer positive, dependable and consistent overcurrent protection ,breakers do not. Breakers are electrical mechanical devices that are affected by age ,corrosion and temperature and have inconsistent trip points. Overcurrent devices protect the equipment as well as the trailer wiring and breakers often allow too much pass thru current to protect equipment . Look at a car radio or a microwave or a TV and they have fuses for overcurrent protection . The advantages of a circuit breaker are the ability to be turned on and off and they are convenient to reset but offer far less protection than a fuse

[stevebaz]

Originally Posted by glennco

Yeah, solid vs stranded wire debate.


1 additional vote for stranded.

An additional question. Does scamp typically use 12awg wire for a power feed? Even fused at 20 amps, 10awg seems like it would be safer, or is that just overkill?

12awg wire is OK for the 20 amps that Scamp origonally installed but that was with limited power useage. By someone changing to a power distribution pannel you are changing the design peramaters. so the incomming line must be upgraded to the power capabilities of the pannel. I doubt that #12 @ 20 amps is up to snuff. Your figures will vary but for example about 5 amps for the fridge, 5 amps for the fan, 5 amps for the water pump. Examples but not limited to 5 amps for each lighting circut and 15 amps for each lighter style socket all this power can be concivably turned on at the same time even if its intermitant it all counts, that 20 amp fuse is gonna blow. It is far safer to upgrade the incoming wire to pannel rating including run wire length. Then fuze limit the incomming line to a load your comfortable with. Go to Walmart in the sterio section or any sterio supplier they have some nice large blade fuze holders with covers if you want to upsize your incomming power line.
My old Scamp had very limited power supplied by Scamp but when I wanted to add more convience items an upgrade had to be done. Right now your system is very suspect and should be wrought out and please follow the proper color codes and wire markings so anyone trouble shooting knows what was actually done.

[Jared J]

Originally Posted by glennco

Yeah, solid vs stranded wire debate.

1 additional vote for stranded.

An additional question. Does scamp typically use 12awg wire for a power feed? Even fused at 20 amps, 10awg seems like it would be safer, or is that just overkill?

When I pulled my old converter out of the scamp, it was 12 gauge&hellip;with. 30 amp bullet fuse!!! The converter was rated for 15! That made me curious, so I hooked it back up and put a 15 amp in it. Smoked it. 20 amp&hellip;smoked it, 25 amp&hellip;smoked it after a minute or two. With the 30, I could barely touch the wire!!

I have no idea why it was that way, if scamp did that, or the p.o. did. That thing was a hair away from bursting into flames. I was ripping out the wiring anyway, so I quit investigating at that point.

I have 4 gauge on a 50 amp marine breaker now.

The other issue I have is with them branching circuits off of circuits. Well, if both require a 10 amp fuse, now you need a 20 amp. What if one of those is off, and the other starts pulling 18 amps?

Originally, all 12v was one circuit. Now it's:

fridge
furnace
water pump
lights
12v power receptacles

The 120v had the ac on one circuit, and the water heater and everything else on the other.

Now it's
Outside/couch/bunk outlets
Rh kitchen outlets/electric fireplace
Fridge/fluorescent light/Lh kitchen outlets
Ac
12v dc converter
Water heater

I prefer to keep everything separate with the lowest fuse/breaker rating needed. Otherwise, you might need one of these:

[Roy in TO]

I'll have to order some of those 530433's. Where did you source it?

[Jared J]

I wish I knew. You'll have to break into the garage of somebody with a british car. Lucas the inventor of the intermittent wipers&hellip;and headlights&hellip;and gauges&hellip;

[JD1994]

This is a great discussion and very helpful in understanding concerns with trailer wiring in general.

You might be interested in the national standard that covers this type of wiring. SAE (Society of Automotive Engineers) J1292

SAE J1292: Automobile, Truck, Truck-Tractor, Trailer, and Motor Coach Wiring

Nothing in it will surprise any of us, but it's nice to see there are standards.

Dave in Baltimore

[Thinh]

...This is my thought thru: experiences... The over-kill wire(bigger size) will not hurt your electrical circuitry but it will add more weights and costs. THE OVER-KILLED FUSE RATINGS WILL COST YOU A WHOLE TRAILER ELECTRICAL CIRCUITRY. Pls do not forget that. That's why hydro suppliers use high voltage; 6000VAC, 230KVAV to deliver hydro to your home for long distance. They want to save cost with smaller size of their wires....Hopefully it helps...

[Brian B-P]

Originally Posted by JD1994

You might be interested in the national standard that covers this type of wiring. SAE (Society of Automotive Engineers) J1292

SAE J1292: Automobile, Truck, Truck-Tractor, Trailer, and Motor Coach Wiring

Nothing in it will surprise any of us, but it's nice to see there are standards.

I agree, it is good to have standards.

I note, though, that the common 7-pin flat-blade "RV" style electrical connection typically does not follow J1292 colour coding. Common 4-pin flat and 7-pin round-pin commercial truck trailer connectors (which are unsuited to electric brake and battery charging functions and rarely used on RVs) do follow this standard.

[glennco]

I figured I'd give everyone a status. I ordered a PD5000 panel and a charge wizard to attach to my PD9130.

Tomorrow I took the day off to work on the install this setup. The design of this PD panel is by far a better designed unit the. The 'American' unit that was in the scamp.

I intend to run new power and ground wires in a larger gauge as well. The previous setup had the power from the tug intersect with the battery + all the way back at the fuse panel. That is a poor design, and I will be moving it back up to the front as the camper would have been when it came from the factory. It will be isolated between two in-line fuses in the same style as per the factory. This effectively isolates the camper from the tug in case of any surges from the tug.

After it's all together, start testing individual devices to see if I can find something drawing too much current.


Any other things anyone can think of?

[glennco]

Wanted to give folks an update here. I tried to run some 8awg wire wire but was unable to fish the wire around the front bath. So, I added the proper fuses separating the battery and camper from the power coming in from the tug. If anyone has ever tried to run new power wire in a scamp with a front bath, I'd be interested in knowing how it was done.

After adding the fuses I found that I blew the fuse between the battery and the tug power on our last trip. This made me start looking more deeply to an issue with the wiring in the tug. I found it, the power wire had gotten too close to the muffler and melted. It as creating an intermittent short to ground when driving. My relay protected the power system of the tug, but the poor wiring from the PO caused the failure of the fuse panel.

Hopefully I won't have another failure on the tug, but am reassured that I've added the necessary segregation to the power system in the scamp to prevent another catastrophic failure if a similar situation arises again

I'd very much appreciate any thoughts folks would have on running new power wire in the scamp. The current 12awg wire scamp runs seems like a weak point in the system d like to eliminate.

Thanks,

Paul

[Jared J]

I ran 4 gauge, but I went under the trailer with it.

[glennco]

I did consider running the wire under the camper, but I go concerned about punching new holes through the floor