Fuse Fire

[mrzed001]

Just a short hint: @Will Prowse can you put this thread to the new Up in smoke topic please

 

[Texas-Mark]

I did not read every reply, but saw several people talking about poor connections. A poor connection will not cause a fuse to glow. A poor connection can cause the actual connection to get hot (and maybe glow) due to the build up of resistance, but is not going to cause more current to magically flow though a fuse and make it glow.

 

[Bob B]

I did not read every reply, but saw several people talking about poor connections. A poor connection will not cause a fuse to glow. A poor connection can cause the actual connection to get hot (and maybe glow) due to the build up of resistance, but is not going to cause more current to magically flow though a fuse and make it glow.

If the bad connection were on the spade of the fuse it sure could.

 

[Texas-Mark]

If the bad connection were on the spade of the fuse it sure could.

Like, I said, the poor connection it's self could, but not likely the whole fuse unless it is just from heat transfer. My point was that poor connections do not increase current flow through other devices (like fuses), If anything, they reduce current flow (through those other devices).

 

[Hedges]

What the poor connection can do is elevate temperature, so fuse or breaker trips at a lower current.
We expect a fuse to go into thermal runaway, so having it sit there glowing seems unlikely.

(Not impossible, if we try hard enough to design a circuit keeping the fuse at an unstable equilibrium. But for any expected load, hotter fuse should increase in resistance and dissipate even more power, racing to the point of burning out.)

 

[Texas-Mark]

What the poor connection can do is elevate temperature, so fuse or breaker trips at a lower current.

Yes, this is true. This is assuming the fuse or breaker is near the point where the poor connection is and the heat is generated. All too often I hear people blame a blown fuse on a bad connection 3 feet away. They seem to think that the bad connection somehow increases the current flow through the protection device.

 

[Hedges]

Which it can in some cases, especially a motor that fails to start.
For switching power supplies, dropped voltage raises current draw in proportion, so if severe enough this might happen. In which case they may have been saved from a fire by the grace of fuse.

In each case, have to consider the loads, rating and type of fuse to figure it out.
I've had a breaker trip on my central A/C; maybe a brief power interruption?. Once on my VFD powered pool pump (original 15A had tripped after installing 3-phase and VFD so I changed to 20A.) But it tripped once recently, I assume something transient but not sure what.

 

[Bob B]

They seem to think that the bad connection somehow increases the current flow through the protection device.

Where did anyone except you say that a bad connection increased current flow?

I can think of some circumstances where that would happen ..... some devices want a certain amount of POWER. If you cause a voltage drop .... they will require more current to get that power.
I don't, however, think that applies to this case.

 

[Texas-Mark]

Where did anyone except you say that a bad connection increased current flow?

I never said that. I said I heard people say it (that it can cause a fuse to blow). I also saw people here immediately blaming a poor connection for the fuse "glowing".

 

[Texas-Mark]

I can think of some circumstances where that would happen ..... some devices want a certain amount of POWER. If you cause a voltage drop .... they will require more current to get that power.
I don't, however, think that applies to this case.

You might find that in an AC circuit where maybe a bad connection somehow causes a locked rotor condition (like in a compressor) and then might draw more current. But in DC circuits like this, more resistance somewhere typically results in less current.

 

[Bob B]

I never said that. I said I heard people say it. I also saw people here immediately blaming a poor connection for the fuse "glowing".

I have seen things glow red hot because of a bad connection .... and seen bad connections get hot enough to cause fires in electronic equipment.
Maybe your perspective is just too limited.

 

[Bob B]

You might find that in an AC circuit where maybe a bad connection somehow causes a locked rotor condition (like in a compressor) and then might draw more current. But in DC circuits like this, more resistance somewhere typically results in less current.

Didn't I say I didn't think it applied to this circumstance?

 

[Texas-Mark]

I have seen things glow red hot because of a bad connection .... and seen bad connections get hot enough to cause fires in electronic equipment.
Maybe your perspective is just too limited.

You don't seem to be reading what I wrote. I clearly said a bad connection "could" glow. What I said is that a fuse not in close proximity won't unless it is from transferred heat.
My perspective is having an electrical engineering degree. But this is Ohm's law 101.

I know I am the new guy around here, but I have been doing electrical for over 40 years. I certainly do not know everything about solar (only been doing that for about 18 years), but current flow is current flow.

 

[Bob B]

You don't seem to be reading what I wrote. I clearly said a bad connection "could" glow. What I said is that a fuse not in close proximity won't unless it is from transferred heat.
My perspective is having an electrical engineering degree. But this is Ohm's law 101.

I know I am the new guy around here, but I have been doing electrical for over 40 years. I certainly do not know everything about solar (only been doing that for about 18 years), but current flow is current flow.

But .... You are ignoring the fact that the spade connection on the fuse is a mechanical connection and is .... part of the fuse body. A bad connection on that spade could easily get hot enough to glow and melt down that fuse holder.
Not trying to say that absolutely was the cause, but you seem to be determined to say it isn't a possibility at all. I have seen similar things happen many many times.
.... and you are trying to belittle anyone who could possibly think that could happen.

 

[mrzed001]

Where did anyone except you say that a bad connection increased current flow?

I can think of some circumstances where that would happen ..... some devices want a certain amount of POWER. If you cause a voltage drop .... they will require more current to get that power.
I don't, however, think that applies to this case.

Bad connections increase resistance, so increase Voltage drop and heat production.
P = I^2 x R (W = A^2 x Ohm)
Bigger resistance, more heat. Also resistance grows with heat (producing more heat that more resistance ... ).
We use this in the (melting) fuses.

Also a page from a product like this fuse holder :
https://www.redarc.com.au/faq-tech-tips/bad-fuses-or-bad-fuse-holders

 

[Texas-Mark]

But .... You are ignoring the fact that the spade connection on the fuse is a mechanical connection and is .... part of the fuse body. A bad connection on that spade could easily get hot enough to glow and melt down that fuse holder.
Not trying to say that absolutely was the cause, but you seem to be determined to say it isn't a possibility at all. I have seen similar things happen many many times.
.... and you are trying to belittle anyone who could possibly think that could happen.

<sigh> You still are not reading what I wrote. I acknowledged multiple times that a bad connection can get hot and glow. I also said that IF that bad connection was on the end of a fuse, that the transferred heat from that connection could possibly also cause the fuse to glow. However, I also said that a bad connection at point A would not cause a fuse located somewhere else (point B) to glow. Not sure why that is so hard to understand.

I am not trying to belittle anyone. I am simply voicing my opinion (based on decades of electrical experience). But whatever, I'm not going to continue to argue about it. Hope the OP'er solves the problem, whatever it was that caused it.

 

[Bob B]

<sigh> You still are not reading what I wrote. I acknowledged multiple times that a bad connection can get hot and glow. I also said that IF that bad connection was on the end of a fuse, that the transferred heat from that connection could possibly also cause the fuse to glow. However, I also said that a bad connection at point A would not cause a fuse located somewhere else (point B) to glow. Not sure why that is so hard to understand.

I am not trying to belittle anyone. I am simply voicing my opinion (based on decades of electrical experience). But whatever, I'm not going to continue to argue about it. Hope the OP'er solves the problem, whatever it was that caused it.

I don't think anyone but you talked about a bad connection somewhere else causing the fuse to glow .... We've all been talking about the fuse itself having a bad connection.
Maybe you didn't understand that since it wasn't always specified where the bad connection might be .... personally, I just assumed that would be obvious.

 

[jwelter99]

Thanks for the responses. Great to find a spot with knowledge of these systems. I am on the boat now so attached are some photos.

One thing to note is I replaced the batteries in the boat probably 3 or 4 weeks ago. I do not remember where the fuse holder was placed exactly before I undid the connections and changed the battery but where it was when it burned up is right over the top of the battery service / fill caps with the battery box cover snug against it. I am wondering if off gassing of the battery could of corroded the fuse? The fuse holder was an anchor marine brand and is pretty well sealed with a gasket but it is something that popped into my mind.

The wire from the solar controller turns out to be 10 gauge but then they butt spliced it to a 12gauge wire fuse holder with the 25amp fuse.

In the pictures the good fuse holder is the one for the starting battery. I also attached a picture of the solar remote meter showing the max amps from solar charge which was 27.21. I am not sure when that max amp was hit. When the melted fuse situation happened it was partly to mostly cloudy. Not to say there were not some holes with sun but it was on and off.

The inverter is pulling power through much larger wire and has a 300amp fuse. The charge wires from the solar charger are run separate directly to the house battery and then the starting battery and each run has its own fuse though as mentioned it is a 12gauge wire with a 25 amp fuse. The length of the wire on the fuse is 4 or 5 " on each side. One side was directly to the battery terminal and the other side is spliced to the 10 gauge wire that runs about 3ft to the solar control.

Do you know where the fuse holder and fuse was sourced? I presume all this was existing and not new work?

 

[Lee R]

Do you know where the fuse holder and fuse was sourced? I presume all this was existing and not new work?

Everything on the Solar setup was existing. The fuse holder was a Blue Seas brand waterproof inline fuse holder. The same fuse holder was used for the house/inverter battery bank and the starting battery. The starting battery fuse shows no corrosion. As I mentioned in an earlier thread I replaced the batteries several weeks prior to the fuse melting. When I put the cover on the battery box the fuse that failed got pushed down with the cover directly over the vent on the battery. The fuse holder is sealed with a gasket but I am wondering if the battery gases could of got in and caused corrosion. When I discovered the smoke and took the cover off the battery box the upper part of the fuse housing where the fuse would have been was burned up and pretty much gone, and there was still a glow between the two sides of the open fuse housing at which time I shut everything down.

I feel whatever happened to the fuse had to be involved with the heavy amp draw on the inverter at the time. If I remember correctly at the time it occurred the inverter panel was reading around 125 amps with the microwave running. I also remember looking at the solar panel somewhere around the time this occurred and it was about 13amps but it was overcast so that was fluctuating as clouds moved over. At the time it happened my wife had used the microwave, then the toaster and then the microwave again so the inverter was getting hit hard for several minutes. The company that makes the solar controller said the inverter can not pull anymore power through than what the solar panel is providing. My question is with the heavy draw on the battery bank, which one side of the fuse is connected to, and the normal say 12-13 watts on the other side coming in from the panel, how can that scenario cause the excess heat that caused the fuse to fail? I do not think the fuse would of burned up like it did with a solar charge coming in and a regular draw on the batteries as it has been operating like that without issue for me. If the draw on the batteries can not pull more amps than what the solar panels are providing does it do anything else like try to pull the power through faster or something that could overheat a connection point? Just trying to get a better understanding.

Since the fuse melted I have had the solar system disconnected but am now in the process of hooking it up again. I ran 8 gauge wire from the solar controller for both battery banks with separate 30amp Midi fuse holders mounted external from the battery box on the bulkhead. I will then be running 8 gauge wire from the fuse holder to a bus bar, mounted externally from the battery box as well, which will have all battery connections other than any sensor wires and wires connecting the battery banks which will be directly to the batteries.

Once it is hooked back up I will run some test putting a heavy load on the inverter and checking amp draw through the wiring. I will post back once I get it going.

 

[mrzed001]

Everything on the Solar setup was existing. The fuse holder was a Blue Seas brand waterproof inline fuse holder. The same fuse holder was used for the house/inverter battery bank and the starting battery. The starting battery fuse shows no corrosion. As I mentioned in an earlier thread I replaced the batteries several weeks prior to the fuse melting. When I put the cover on the battery box the fuse that failed got pushed down with the cover directly over the vent on the battery. The fuse holder is sealed with a gasket but I am wondering if the battery gases could of got in and caused corrosion. When I discovered the smoke and took the cover off the battery box the upper part of the fuse housing where the fuse would have been was burned up and pretty much gone, and there was still a glow between the two sides of the open fuse housing at which time I shut everything down.

I feel whatever happened to the fuse had to be involved with the heavy amp draw on the inverter at the time. If I remember correctly at the time it occurred the inverter panel was reading around 125 amps with the microwave running. I also remember looking at the solar panel somewhere around the time this occurred and it was about 13amps but it was overcast so that was fluctuating as clouds moved over. At the time it happened my wife had used the microwave, then the toaster and then the microwave again so the inverter was getting hit hard for several minutes. The company that makes the solar controller said the inverter can not pull anymore power through than what the solar panel is providing. My question is with the heavy draw on the battery bank, which one side of the fuse is connected to, and the normal say 12-13 watts on the other side coming in from the panel, how can that scenario cause the excess heat that caused the fuse to fail? I do not think the fuse would of burned up like it did with a solar charge coming in and a regular draw on the batteries as it has been operating like that without issue for me. If the draw on the batteries can not pull more amps than what the solar panels are providing does it do anything else like try to pull the power through faster or something that could overheat a connection point? Just trying to get a better understanding.

Since the fuse melted I have had the solar system disconnected but am now in the process of hooking it up again. I ran 8 gauge wire from the solar controller for both battery banks with separate 30amp Midi fuse holders mounted external from the battery box on the bulkhead. I will then be running 8 gauge wire from the fuse holder to a bus bar, mounted externally from the battery box as well, which will have all battery connections other than any sensor wires and wires connecting the battery banks which will be directly to the batteries.

Once it is hooked back up I will run some test putting a heavy load on the inverter and checking amp draw through the wiring. I will post back once I get it going.

It is clear that bad connection inside the fuse holder was the cause of its melting.
Also I think the fuse is still working in it (even it is burned). So if you check there will be continuity between the fuse two cables.

For solar cable you can use MC4 fuses like: https://www.aliexpress.com/item/32813237341.html

For big battery fuse (and separator) I recommend big fuses like NH1:

 

[jwelter99]

Everything on the Solar setup was existing. The fuse holder was a Blue Seas brand waterproof inline fuse holder. The same fuse holder was used for the house/inverter battery bank and the starting battery. The starting battery fuse shows no corrosion. As I mentioned in an earlier thread I replaced the batteries several weeks prior to the fuse melting. When I put the cover on the battery box the fuse that failed got pushed down with the cover directly over the vent on the battery. The fuse holder is sealed with a gasket but I am wondering if the battery gases could of got in and caused corrosion. When I discovered the smoke and took the cover off the battery box the upper part of the fuse housing where the fuse would have been was burned up and pretty much gone, and there was still a glow between the two sides of the open fuse housing at which time I shut everything down.

I feel whatever happened to the fuse had to be involved with the heavy amp draw on the inverter at the time. If I remember correctly at the time it occurred the inverter panel was reading around 125 amps with the microwave running. I also remember looking at the solar panel somewhere around the time this occurred and it was about 13amps but it was overcast so that was fluctuating as clouds moved over. At the time it happened my wife had used the microwave, then the toaster and then the microwave again so the inverter was getting hit hard for several minutes. The company that makes the solar controller said the inverter can not pull anymore power through than what the solar panel is providing. My question is with the heavy draw on the battery bank, which one side of the fuse is connected to, and the normal say 12-13 watts on the other side coming in from the panel, how can that scenario cause the excess heat that caused the fuse to fail? I do not think the fuse would of burned up like it did with a solar charge coming in and a regular draw on the batteries as it has been operating like that without issue for me. If the draw on the batteries can not pull more amps than what the solar panels are providing does it do anything else like try to pull the power through faster or something that could overheat a connection point? Just trying to get a better understanding.

Since the fuse melted I have had the solar system disconnected but am now in the process of hooking it up again. I ran 8 gauge wire from the solar controller for both battery banks with separate 30amp Midi fuse holders mounted external from the battery box on the bulkhead. I will then be running 8 gauge wire from the fuse holder to a bus bar, mounted externally from the battery box as well, which will have all battery connections other than any sensor wires and wires connecting the battery banks which will be directly to the batteries.

Once it is hooked back up I will run some test putting a heavy load on the inverter and checking amp draw through the wiring. I will post back once I get it going.

I asked as a lot of counterfeit stuff on Amazon.

I avoid Amazon and pay a bit more to go with a known-distributor. Even then you need to take a careful look as they are not immune either.

Your issue could have been counterfeit fuse holder, fuse, or perhaps just unlucky and somehow it became corroded which led to the overheating.

Glad you were around to catch the smell and get it under control before it could become a bigger issue.

PS: You should reach out to BlueSea over this directly as well - they likely would like to get the melted parts back to do a failure analysis.

 

[Lee R]

Hello all, I finished installing the heavier gauge wire for the solar panel charging as well as installing the MIDI fuse holders. I also added terminals blocks to clean up the wiring on the battery terminals themselves. Next step is to run some test on the system. attached are some pictures. Earlier in the posts I have pictures of the before. Thanks for all the tips!

 

[HRTKD]

Looks good Lee. You made some nice improvements.

 

[Smokin]

So the Microwaves going and the house battery is draining and saging and the engine battery is flowing current through the charge wire that is mistakenly connecting both batteries, and the current over time is climbing and melting the fuse holder. This is because some idot wired that boat. You use a diodes to send power to both batteries so this doesnt happen.
see like this https://www.amazon.com/Victron-Ener...cphy=9008590&hvtargid=pla-1164727432478&psc=1

any questions.
I would contact the boat manufacture and find out why the did it this way. If they blow you off contact their Insurance carrier.