# Help With A Blown Fuse



## vvsarpsjr (Aug 17, 2008)

A couple of weekends ago when winterizing the OB, when I was just about done the GF circuit in the panel tripped and the 15amp fuse blew. I had the air compressor plugged into the the outdoor outlet on the OB and the OB pluged in to a land line. The compressor says it draws 10 amps and nothing else was being used on the circuit. I then reset the GF circuit breaker and tried to replace the 15amp fuse but even trying to replace the fuse was causing sparks. Does anybody know what happen or where the short is? I have not been able to find it and all other circuits are working fine. The GF outlet in the bathroom was also tripped and I have not been able to reset it but that is because it is not receiving power. Thanks for any advise.


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## hautevue (Mar 8, 2009)

I would:

1. disconnect the land line. I assume that the land line is an extension cord plugged into your house on a 15 amp circuit? You say you replaced the fuse--is that 15 amp fuse separate from the main house panel (where I presume you have circuit breakers)?

Disconnect the land line from the TT. Plug the compressor into the 15 a circuit directly. If the fuse blows instantly, you know that the compressor has a problem. Many compressors that "run on 10 amps" take 15 - 20 amps to start. You may need a slow-blow fuse that will allow a momentary (2 or 3 second) overload so the compressor starts. The TT air conditioner has the same issue--it may draw 12 amps running, but takes 20 - 25 amps to crank up. But you may have a short in the compressor motor.

2. If the compressor is fine, then you need to check the TT lines. Put your friendly volt-ohmmeter on the TT shore power cable, which is not plugged into anything. The resistance from one angled prong to ground (the round prong) should not be zero. The other angled prong is grounded, so the resistance on that one would be zero. The resistance should be high, i.e., there is no electrical path between one of the prongs and ground. If both prongs have very low resistance, you have a short in the TT.

I would now get an electrician to help--I'd need to write a lot of info to tell you how I'd go through the diagnosis of finding a short. Good luck!


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## vvsarpsjr (Aug 17, 2008)

hautevue said:


> I would:
> 
> 1. disconnect the land line. I assume that the land line is an extension cord plugged into your house on a 15 amp circuit? You say you replaced the fuse--is that 15 amp fuse separate from the main house panel (where I presume you have circuit breakers)?
> 
> ...


I don't think I explained very well what the situation was. The OB shore power cable was plugged into a 15 amp circuit in the adjacent barn. I was using the compressor that was plugged into the Outback exterior outlet via a 14g extension cord. The compressor all of the sudden quit and inside the OB inverter panel found that the circuit breaker that is labeled GF had tripped and the red light on the bottom most 15 amp fuse was light. I disconnected the compressor from the OB exterior outlet and finished the job with it plugged into the barn circuit. I then reset the tripped GF circuit breaker in the OB panel without a problem. I then removed the 15 amp fuse from the panel and when trying to replace a new one it is immediately trying to melt it. I tested the OB shore power cable plug as you suggested and both prongs have very low resistance. So the short appears to be within the OB and I have no idea of where to start looking and why did it happen? Could the GF outlet in the bathroom be bad or damaged? That would be the easiest to repair but probably more involved than that.


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## outback loft (Sep 22, 2008)

Well you are talking about two completely separate systems, the 15 amp breaker that you reset was on the 120 volt side of power, and the 15 amp fuse that is blown is on the 12 volt side. If you are still not getting power from where the compressor was plugged in, you not only popped the circuit breaker, but also popped the GFCI outlet, there is a reset on one of the outlets, it may be the kitchen outlet. If the GFCI in my kitchen blows, my outside outlet goes out with it. The other thing with a GFCI is that if there is no power to it, you cannot reset it until there is power. You more than likely were drawing too much power with the compressor plugged into the trailer, which in turn was plugged into a 14 gauge cord. A 14 gauge cord is rated for 15 amps, but you need to remember that you had the compressor going and more than likely when the trailer was plugged in, your batter charger/converter kicked in as well.

The 15 amp fuse that is blown is on the 12 volt side and if it is sparking when you are trying to put a new one in, there is something drawing power from that circuit. You can disconnect the battery and replace the fuse. If it blows again, then there is a short in that line.


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## vvsarpsjr (Aug 17, 2008)

outback loft said:


> Well you are talking about two completely separate systems, the 15 amp breaker that you reset was on the 120 volt side of power, and the 15 amp fuse that is blown is on the 12 volt side. If you are still not getting power from where the compressor was plugged in, you not only popped the circuit breaker, but also popped the GFCI outlet, there is a reset on one of the outlets, it may be the kitchen outlet. If the GFCI in my kitchen blows, my outside outlet goes out with it. The other thing with a GFCI is that if there is no power to it, you cannot reset it until there is power. You more than likely were drawing too much power with the compressor plugged into the trailer, which in turn was plugged into a 14 gauge cord. A 14 gauge cord is rated for 15 amps, but you need to remember that you had the compressor going and more than likely when the trailer was plugged in, your batter charger/converter kicked in as well.
> 
> The 15 amp fuse that is blown is on the 12 volt side and if it is sparking when you are trying to put a new one in, there is something drawing power from that circuit. You can disconnect the battery and replace the fuse. If it blows again, then there is a short in that line.


Thanks for the explanation. For some reason now the GFCI outlet in the bathroom can be reset and the outlets on the circuit now all work. I didn't change anything just came back later and tried to reset it again. Seems like the 120V side is working properly again but didn't place a load on it yet. On the DC side, still can't replace the 15 amp fuse without it blowing. Must be a short on the DC circuit but was that coincidence and perhaps was already there before I overloaded the 120V side and needed to look at the panel. I don't see how the two would be related.


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## outback loft (Sep 22, 2008)

vvsarpsjr said:


> Well you are talking about two completely separate systems, the 15 amp breaker that you reset was on the 120 volt side of power, and the 15 amp fuse that is blown is on the 12 volt side. If you are still not getting power from where the compressor was plugged in, you not only popped the circuit breaker, but also popped the GFCI outlet, there is a reset on one of the outlets, it may be the kitchen outlet. If the GFCI in my kitchen blows, my outside outlet goes out with it. The other thing with a GFCI is that if there is no power to it, you cannot reset it until there is power. You more than likely were drawing too much power with the compressor plugged into the trailer, which in turn was plugged into a 14 gauge cord. A 14 gauge cord is rated for 15 amps, but you need to remember that you had the compressor going and more than likely when the trailer was plugged in, your batter charger/converter kicked in as well.
> 
> The 15 amp fuse that is blown is on the 12 volt side and if it is sparking when you are trying to put a new one in, there is something drawing power from that circuit. You can disconnect the battery and replace the fuse. If it blows again, then there is a short in that line.


Thanks for the explanation. For some reason now the GFCI outlet in the bathroom can be reset and the outlets on the circuit now all work. I didn't change anything just came back later and tried to reset it again. Seems like the 120V side is working properly again but didn't place a load on it yet. On the DC side, still can't replace the 15 amp fuse without it blowing. Must be a short on the DC circuit but was that coincidence and perhaps was already there before I overloaded the 120V side and needed to look at the panel. I don't see how the two would be related.
[/quote]

If you disconnect the battery before replacing the fuse, then reconnect it after it is changed does it still blow? If so then there is a short, if not there may have just been a load on it and when you are trying to put the fuse in the sparking may just be blowing the new fuse. The other thing to check is there should be a bus bar with all the negative wires tucked in behind the converter, maybe a wire has worked loose and is touching a positive side wire. The two may be related, but I doubt it, there is a chance the fuse was blown before and it was never noticed. I have had that happen before and not noticed it until another trip out.


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## vvsarpsjr (Aug 17, 2008)

outback loft said:


> Well you are talking about two completely separate systems, the 15 amp breaker that you reset was on the 120 volt side of power, and the 15 amp fuse that is blown is on the 12 volt side. If you are still not getting power from where the compressor was plugged in, you not only popped the circuit breaker, but also popped the GFCI outlet, there is a reset on one of the outlets, it may be the kitchen outlet. If the GFCI in my kitchen blows, my outside outlet goes out with it. The other thing with a GFCI is that if there is no power to it, you cannot reset it until there is power. You more than likely were drawing too much power with the compressor plugged into the trailer, which in turn was plugged into a 14 gauge cord. A 14 gauge cord is rated for 15 amps, but you need to remember that you had the compressor going and more than likely when the trailer was plugged in, your batter charger/converter kicked in as well.
> 
> The 15 amp fuse that is blown is on the 12 volt side and if it is sparking when you are trying to put a new one in, there is something drawing power from that circuit. You can disconnect the battery and replace the fuse. If it blows again, then there is a short in that line.


Thanks for the explanation. For some reason now the GFCI outlet in the bathroom can be reset and the outlets on the circuit now all work. I didn't change anything just came back later and tried to reset it again. Seems like the 120V side is working properly again but didn't place a load on it yet. On the DC side, still can't replace the 15 amp fuse without it blowing. Must be a short on the DC circuit but was that coincidence and perhaps was already there before I overloaded the 120V side and needed to look at the panel. I don't see how the two would be related.
[/quote]

If you disconnect the battery before replacing the fuse, then reconnect it after it is changed does it still blow? If so then there is a short, if not there may have just been a load on it and when you are trying to put the fuse in the sparking may just be blowing the new fuse. The other thing to check is there should be a bus bar with all the negative wires tucked in behind the converter, maybe a wire has worked loose and is touching a positive side wire. The two may be related, but I doubt it, there is a chance the fuse was blown before and it was never noticed. I have had that happen before and not noticed it until another trip out.
[/quote]

It still blows when the battery is reconnected so there is a short somewhere, ugh. Thanks for the advice, I will check the bus bar tomorrow. If not that I feei that I will be looking for the proverbial needle in the haystack.


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## outback loft (Sep 22, 2008)

vvsarpsjr said:


> Well you are talking about two completely separate systems, the 15 amp breaker that you reset was on the 120 volt side of power, and the 15 amp fuse that is blown is on the 12 volt side. If you are still not getting power from where the compressor was plugged in, you not only popped the circuit breaker, but also popped the GFCI outlet, there is a reset on one of the outlets, it may be the kitchen outlet. If the GFCI in my kitchen blows, my outside outlet goes out with it. The other thing with a GFCI is that if there is no power to it, you cannot reset it until there is power. You more than likely were drawing too much power with the compressor plugged into the trailer, which in turn was plugged into a 14 gauge cord. A 14 gauge cord is rated for 15 amps, but you need to remember that you had the compressor going and more than likely when the trailer was plugged in, your batter charger/converter kicked in as well.
> 
> The 15 amp fuse that is blown is on the 12 volt side and if it is sparking when you are trying to put a new one in, there is something drawing power from that circuit. You can disconnect the battery and replace the fuse. If it blows again, then there is a short in that line.


Thanks for the explanation. For some reason now the GFCI outlet in the bathroom can be reset and the outlets on the circuit now all work. I didn't change anything just came back later and tried to reset it again. Seems like the 120V side is working properly again but didn't place a load on it yet. On the DC side, still can't replace the 15 amp fuse without it blowing. Must be a short on the DC circuit but was that coincidence and perhaps was already there before I overloaded the 120V side and needed to look at the panel. I don't see how the two would be related.
[/quote]

If you disconnect the battery before replacing the fuse, then reconnect it after it is changed does it still blow? If so then there is a short, if not there may have just been a load on it and when you are trying to put the fuse in the sparking may just be blowing the new fuse. The other thing to check is there should be a bus bar with all the negative wires tucked in behind the converter, maybe a wire has worked loose and is touching a positive side wire. The two may be related, but I doubt it, there is a chance the fuse was blown before and it was never noticed. I have had that happen before and not noticed it until another trip out.
[/quote]

It still blows when the battery is reconnected so there is a short somewhere, ugh. Thanks for the advice, I will check the bus bar tomorrow. If not that I feei that I will be looking for the proverbial needle in the haystack.
[/quote]

To help in locating where the short is go around and turn on lights, fans, heat, refrigerator, etc, all while on battery power only. If you find something that doesn't work you can then use that as a starting point to trace wires.


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## john7349 (Jan 13, 2008)

As for the 120V side, you may have had a short in the outside plug itself. If you plug something in again, you might wiggle a wire and cause another momentary short. Remove the Plug and check the wiring.

The 12V side? Perhaps it was already blown and is a separate issue. That's my 2cents.....


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## CamperAndy (Aug 26, 2004)

Have you identified what 12 vdc circuit is not working due to the blown fuse? If you can then we would work back from there. Don't just keep replacing the fuse hoping it will get better, it won't.


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## Jewellfamily (Sep 25, 2010)

vvsarpsjr said:


> Well you are talking about two completely separate systems, the 15 amp breaker that you reset was on the 120 volt side of power, and the 15 amp fuse that is blown is on the 12 volt side. If you are still not getting power from where the compressor was plugged in, you not only popped the circuit breaker, but also popped the GFCI outlet, there is a reset on one of the outlets, it may be the kitchen outlet. If the GFCI in my kitchen blows, my outside outlet goes out with it. The other thing with a GFCI is that if there is no power to it, you cannot reset it until there is power. You more than likely were drawing too much power with the compressor plugged into the trailer, which in turn was plugged into a 14 gauge cord. A 14 gauge cord is rated for 15 amps, but you need to remember that you had the compressor going and more than likely when the trailer was plugged in, your batter charger/converter kicked in as well.
> 
> The 15 amp fuse that is blown is on the 12 volt side and if it is sparking when you are trying to put a new one in, there is something drawing power from that circuit. You can disconnect the battery and replace the fuse. If it blows again, then there is a short in that line.


Thanks for the explanation. For some reason now the GFCI outlet in the bathroom can be reset and the outlets on the circuit now all work. I didn't change anything just came back later and tried to reset it again. Seems like the 120V side is working properly again but didn't place a load on it yet. On the DC side, still can't replace the 15 amp fuse without it blowing. Must be a short on the DC circuit but was that coincidence and perhaps was already there before I overloaded the 120V side and needed to look at the panel. I don't see how the two would be related.
[/quote]

If you disconnect the battery before replacing the fuse, then reconnect it after it is changed does it still blow? If so then there is a short, if not there may have just been a load on it and when you are trying to put the fuse in the sparking may just be blowing the new fuse. The other thing to check is there should be a bus bar with all the negative wires tucked in behind the converter, maybe a wire has worked loose and is touching a positive side wire. The two may be related, but I doubt it, there is a chance the fuse was blown before and it was never noticed. I have had that happen before and not noticed it until another trip out.
[/quote]

It still blows when the battery is reconnected so there is a short somewhere, ugh. Thanks for the advice, I will check the bus bar tomorrow. If not that I feei that I will be looking for the proverbial needle in the haystack.
[/quote]
Notice your rig is a 2010 310BHS. Is it still under warranty? If so, save yourself some headache and let the service department find it. They will have access to factory schematics, etc...


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## vvsarpsjr (Aug 17, 2008)

Been meeting to reply that I did eventually find what was blowing the fuse. The short was in a wire that went to the bunk light in the rear slide. The wire was within some ridged soft plastic conduit but it was run in such as way that when the slide would close it would pinch the wire/conduit. Eventually it frayed the wire and caused the short. Hope that helps if someone else has a similar problem


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## Nathan (Jan 2, 2007)

Glad to hear you found the short!


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