Fuse instantly blows

[Marsh707]

Hi, i own a 2010 8528 fifthwheel trailer. I recently setup for the season and immediatley noticed a blown fuse(with red light indicator). I tried several times to replace the 15 amp fuse but it sparks and blows instantly. It is the number 2 slot on the electrical box blelow the refrigerator.

Reading on the subject i blive i may have a short. The fuse is connected to four lights in my living room slideout, one under counter light and the stove ventilation unit. I opened them all and only noticed that the light pver my dining room table had several internal wires which the isolation seem pinched/crushed so i disconnected the light completely and removed it. However problem still persists. Need help please!

[jrs_diesel]

Blowing the fuse instantly does indicate a dead short in the wiring or in the device/appliance on that circuit.

Since you have crushed wiring, that is highly suspect and likely your problem. If the light is downstream on the crushed wire, removing the light will not isolate the problem. Usually when a wire gets crushed, the wire itself gets exposed. And when that happens, all it takes if for that wire to touch the chassis/ground wire, and you have a short.

Too fix it you will have to carefully inspect the wire run. If the wire is significantly damaged, it will have to get replaced. Whatever is causing it to get pinched/crushed will have to get fixed too.

[Marsh707]

Originally Posted by jrs_diesel

Blowing the fuse instantly does indicate a dead short in the wiring or in the device/appliance on that circuit.

Since you have crushed wiring, that is highly suspect and likely your problem. If the light is downstream on the crushed wire, removing the light will not isolate the problem. Usually when a wire gets crushed, the wire itself gets exposed. And when that happens, all it takes if for that wire to touch the chassis/ground wire, and you have a short.

Too fix it you will have to carefully inspect the wire run. If the wire is significantly damaged, it will have to get replaced. Whatever is causing it to get pinched/crushed will have to get fixed too.

Thank you for the quick response, the crushed wiring was withon the light fixture. I removed the fixture completely(cut the two wires connected to the fixture) and the problem persists(wires ard simply hanging from the ceiling, not connected to anything nor each other

[OldCoot]

Originally Posted by Marsh707

Thank you for the quick response, the crushed wiring was withon the light fixture. I removed the fixture completely(cut the two wires connected to the fixture) and the problem persists(wires ard simply hanging from the ceiling, not connected to anything nor each other

If the light is in the slide, I would inspect under the slide for a pinched wire. Had one on ours as soon as we got home from the dealer and put the slide out and poof, blew a fuse. Found the problem where the wire runs from the bottom of the slide and starts up the side.

[Marsh707]

Originally Posted by OldCoot

If the light is in the slide, I would inspect under the slide for a pinched wire. Had one on ours as soon as we got home from the dealer and put the slide out and poof, blew a fuse. Found the problem where the wire runs from the bottom of the slide and starts up the side.

I will definately have a look. Would sure beat having to play with the wiring within the . Thank you.

[Marsh707]

Originally Posted by Marsh707

I will definately have a look. Would sure beat having to play with the wiring within the . Thank you.

I finally checked the underside of the slide out. Wire looks fine. Could the cicuit bourd on the control panel be malfunctionning? I could remove another 15amp wire from the circuit and replace ith with the wiring that i currently have trouble with. If the fuse blows. Ir would indicate a ahort of some sort . If it works then it would indicate a problem with my #2 slor on rhe circuit board. Any thoughts?

[avolnek]

You can sure try that and you are correct that it would verify if the slot is good or not... Highly un likely that the slot on the board is bad though. As others suggested the wire is being pinched somewhere by something. Continuing to replace the fuse or replacing with a larger fuse is only going to stress the wires even more and even lead to a possible fire.

Can you give us more details as to what is on the fuse? What are the items that aren't working?

[Marsh707]

Originally Posted by avolnek

You can sure try that and you are correct that it would verify if the slot is good or not... Highly un likely that the slot on the board is bad though. As others suggested the wire is being pinched somewhere by something. Continuing to replace the fuse or replacing with a larger fuse is only going to stress the wires even more and even lead to a possible fire.

Can you give us more details as to what is on the fuse? What are the items that aren't working?

Sure, there are 4 lights in my livingroom slideout, one light over my kitchen counter, the range hood and i notices one light in the kids bedroom slideout

[avolnek]

Well I would have to say the most likely culprit would be the cabling running from the underside of the main camper to the slide where it hangs and is exposed. I have seen some where the wires are held out of the way with springs, maybe that rubbed through?

If it's not in the slides, I would try to find the wiring running to the kitchen area. It could possibly be a loose wire hanging in the range hood...

Do you have access to an ohm meter and know how to use one?

[Marsh707]

I verified the exposed wiring under the slideout. Looks fine . However i found it strange that was able to pull the wiring coming from the main trailer passing theough the steel bars that support the slidout. As for the ohm meter, could always purchase one. Have a feeling it will be very userul in the futur.

[avolnek]

A multi meter (ohm meter) is a very useful tool for diagnosing... I am an electrician by trade so I have plenty!

I still can't get passed thinking the wire is being pinched somewhere... somewhere under the main belly of the camper, or as you were saying where it is passing through steel beam...

If you are for certain that it's not a wire from the under side, I'd suggest pulling the stove hood as it is a steel container that is grounded with wires inside... If I had a multi meter I'd first check to see if the hood had continuity to the frame, which it should, as that is your ground. Then I'd check to see if the hood had continuity to the fuse holder, which is is direct contact with the hot wire that is suspected to be grounded causing the short. If the hood had continuity on either side of the fuse then the hot wire is coming in contact with the hood somewhere...

[Marsh707]

Ok thanks. I will purchase one and will try that . I hope its not the wiring beneath the floor since it looks impossible to get at.

[Marsh707]

Originally Posted by Marsh707

Ok thanks. I will purchase one and will try that . I hope its not the wiring beneath the floor since it looks impossible to get at.

Just a thought, if i were to disconnect every item one by one, would i be able to isolate the problem

[avolnek]

It's a possibility but with how things are typically wired I'm going to say it's probably going to be more of a waste of time. If you get really desperate after searching you could cut the wire to one slide and then check it. If it solves it then the issue is down stream from there... Not the preferred method but I have had to do this a time or two in homes...

[Marsh707]

Originally Posted by avolnek

It's a possibility but with how things are typically wired I'm going to say it's probably going to be more of a waste of time. If you get really desperate after searching you could cut the wire to one slide and then check it. If it solves it then the issue is down stream from there... Not the preferred method but I have had to do this a time or two in homes...

Ok.i m really hoping that the short is in the kitchen and not in the subfloor....

[Marsh707]

I opened the electrical box and a position 2(wheee the little red light turn on) there are three wires connected together(i suspect one is for my slide out interior lights, another for the stove hood and light and the third a light on the children slide out room). I disconnected them from each other and hooked rhem idividually to the electrical box. Darn all three still have the red light when i plug the rv. Now i m definately not an electrician however i dont believe all three wires shorted an the same time (unless. They are somehow somewhere inter connected someplace else.) Please help.

[Witch Doctor]

If you can isolate the three wires that you said are hooked together. try one at a time as you re hook them up. if all 3 will blow the fuse it will be where they are connected together. Your problem can be a nightmare but I'm sure you can isolate each area good luck. Forget calling FR for a wiring diagram they will not have one, they told me it depends on the line who ran them they are all different. That's just so hard for me to believe.But I tried to get one, and that was their responds to me.

[Marsh707]

Originally Posted by gljurczyk

If you can isolate the three wires that you said are hooked together. try one at a time as you re hook them up. if all 3 will blow the fuse it will be where they are connected together. Your problem can be a nightmare but I'm sure you can isolate each area good luck. Forget calling FR for a wiring diagram they will not have one, they told me it depends on the line who ran them they are all different. That's just so hard for me to believe.But I tried to get one, and that was their responds to me.

Thats exactly what i did,,all three blow fuses,,,cant understand why

[OldCoot]

Originally Posted by Marsh707

Thats exactly what i did,,all three blow fuses,,,cant understand why

You are going to have to find where the 3 connect and where they are touching a ground. I would start by pulling the electrical panel and look very closely where those 3 wires exit the box.

[Marsh707]

Originally Posted by OldCoot

You are going to have to find where the 3 connect and where they are touching a ground. I would start by pulling the electrical panel and look very closely where those 3 wires exit the box.

Pulled the panel box. Fuse number 2. There are the 3 wires connected together and a pigtail(i believe thats what it is callee, single wire running from the three to the panel). Alll three grounds looked ok so i removed the three wires from each other including grounds, them hooked them on by one to the panel ( using same pig tail, making sure the right grounds were hooked also). All three short each their turn. Just realized that i used the same pigtain for each test, cant believe that was the problem...could it (defective wire-pigtail)?