2nd start of fire in electrical equipment, what are your experiences ?

[Mambo42]

Yesterday we had our second scare in a one year period. Luckily we were onboard when I suddenly smelled the typical scent of an electrical fire. So I jumped in the lazarette, shut everything down and found out that the connection of the cables of one solar panel, leading into the MPPT controller had come loose and subsequently started the melting of the connection block on the MPPT controller.
Would I not have intervened it would have ended up in a fire and possibly loss of the whole boat.

Last year I also had a beginning fire and the cause of the fire was identical, the screws holding the cable had loosened up due to the vibrations of the boat in heavy seas. After the first fire I decided to check all the connections every month, which means that every month I tighten up all the screws / nuts which connect cables. The last time I did it was 3 weeks ago, since that time we have put another 50 hours on the engines and quite a bit of it was in rough weather, so a lot of vibrations.

My question is if anyone has the same problems with connections coming loose and if so, what did you do to stop them from coming loose ? It is absurd that I have to start checking all the connections now on a weekly basis, there has to be a better solution. Unfortunately the producer of the equipment has the position that there is nothing wrong, it is all a matter of incorrect installation by a non knowledgeable installer according to them. I.o.w. not their problem and no need to change anything in the design.
Reason ?
This MPPT controller needs a 5 mm2 cable with cable shoe.
In the country where this equipment was installed a 5 mm2 cable is not available, it is either 4 or 6 mm2 and thus the 6 mm2 was used. As a result however the combination of 6 mm2 plus cable shoe does not fit in the connection block of the MPPT controller and thus the shoe was left out. According to the producer that is the cause of the problem and it is not their problem, I should have used to correct cable and shoe. The fact that those are perhaps not for sale in certain countries does not register with them.

I have e-mailed with a representative of this company and must say that it is clear I am dealing with a sales person. Everything is the mistake of the user and company that installed it. He even went so far that I should tell companies to go to the producer for further training, i.o.w. I have to start doing their job.

Anyway, if anyone has similar experiences I would like to hear it, but mostly I am looking for solutions to stop the cables from coming loose while underway.

 

[mvweebles]

Thanks for posting this Mambo. Something I had never considered but will add to the list.

For whatever reason, Victron terminal connectors have always been undersized. There is much to recommend to Victron architecture, but I find it lacking in several ways. Scalable connections being one.

Glad to see disaster was averted in your instance.

Peter

 

[mbevins]

Use locktite on the threads, there's temporary and permanent, different colors, blue and red

 

[Gypsy Island]

Hi Mambo,
obviously the cables are not properly sized and should go deeper into the terminal.
To be on the safe side i would suggest to use a controller that could accept more current, so the terminals would not be the problem in this case.
I have two solar arrays, one 940 Watts and the other 650 Watts, both 12 Volt and each parallel wired, so there is plenty of current. I use two Victron Mppt's 150/70 wired with 35 mm2 cable.
There is no need for using cable shoes as Victrons terminals have an intermediate metal plate between the screw and the shell so the strands wouldn't be harmed.
In addition i'm using an infrared camera on my smartphone to check temperatures from time to time.
So far no problems at all.

 

[Gypsy Island]

Another point i've just seen, your cable is in general the wrong type, as there are not enough strands.
Have a look at Victrons manual where they point this out with pictured examples.

 

[Bmarler]

I know this is the wrong size for your cable, but have a look at this style of ferrule. You can collect a larger cable properly, and it fits the small terminal block sizes.

150730 : PIDG Crimp Wire Pins, Tabs & Ferrules

Get 150730 PIDG Crimp Wire Pins, Tabs & Ferrules specs, pricing, inventory availability, and more from TE Connectivity. Get a sample or request a quote.

www.te.com

 

[DavidM]

Wow, this is a serious problem. First, what is the size in watts of your panels and what is their nominal voltage, 12 or 24.

I can just barely see the label in your pic, but it looks like a 100 amp controller. The are usually rated by amperage out to the batteries and the amperage in from the panels will be less than half of that for 24V panels.

5 mm wire diameter is roughly equivalent to #4 AWG which would be required for 12V nominal panels. But if you are using 24V panels, it can be smaller. But #4 gauge marine wire is widely available in the US.


So, are you now?

I agree, that wire is not fine strand marine wire, which may be the root of the problem.

Finally, what is a wire shoe?

Tell us more about your system so we can find a way to fix it. This is definitely a serious problem.

David

 

[SteveK]

WAG. Have you considered a terminal block (with fuse) to end the 6mm and then a short 4mm into MPPT to be able to use the shoe.

 

[ksanders]

The root cause of your fires is the poor connection to the terminal block.

You used oversized wire and tried to stuff it in the connector.
Also in my opinion you are not stripping back enough conductor.

in My opinion the correct fix is to add a terminal to the conductor that will fit in the terminal, or use the correct size wire for the terminal.

The problem is Not the Victron equipment. The terminals they use are standard in our industry and are in use world wide. This is a installation problem, and demonstrates the risks of DIY installations.

 

[luna]

If you used the wrong size wire and did not use the shoe how is that Victron’s problem?

They or their supplier have undoubtably tested the connection and recommend to use what works.

To me it appears that you are asking Victron to do your job, properly install the product, not the other way around.

Once the shoe is installed on the wire, in so far as the connection is concerned, the number of wire strands would be irrelevant.

Many of us in the west believe that type 3 wire stranding (all strands 0.01” dia.) found in the typical Ancor boat cable is the only wire acceptable.
ABYC accepts type 2 stranding with its much larger strands for general wiring.

Looks like you need to replace the device as it’s gotten too hot. Replace the wiring as well.

 

[mvweebles]

in My opinion the correct fix is to add a terminal to the conductor that will fit in the terminal, or use the correct size wire for the terminal.

Kevin - can you provide more information please? When you say add a proper sized terminal to the conductor, are referring to the ferrule setup shown in Bmarlers post #6? Or an interim terminal block to step-down size suggested in post #8? I don't recall exactly, but this is a fairly common issue I've encountered with Victron devices such as MPPT controllers or DC-DC chargers. Terminals are sized for #8 conductor (I don't remember exactly - might be #6) but given the amperage and use (meaning distance between the end points) often requires heavier cable at 12v.

What is the proper way to transition large conductor size down to a smaller terminal connection?

Thanks in advance

Peter

 

[tiltrider1]

Mambo42, thanks for being brave enough to post this issue. A lot of readers will silently learn from this event.

Poor connections is the number one cause of boat fires.

 

[Turtle Blues]

I'm going to rant in another direction.
Yes they are standard to the industry. The electronics industry. They were not developed with the marine environment even a consideration. They are simply an off the shelf assembly component.
The crimp pin is a questionable solution if heavy strand wire is already in place. A step up is to add a terminal strip or individual sealing crimp connectors with short jumpers of the proper sized fine strand wire as the final connection to the green strip. Most install literature cautions against both the pin and soldered wire ends leaving this the only alternative short of replacing the entire existing wiring run which becomes the best choice by default.

 

[Mambo42]

The root cause of your fires is the poor connection to the terminal block.

You used oversized wire and tried to stuff it in the connector.
Also in my opinion you are not stripping back enough conductor.

in My opinion the correct fix is to add a terminal to the conductor that will fit in the terminal, or use the correct size wire for the terminal.

The problem is Not the Victron equipment. The terminals they use are standard in our industry and are in use world wide. This is a installation problem, and demonstrates the risks of DIY installations.

The official size of the required wire was 5 mm2, but that cable is next to impossible to get in Greece. Therefore you have a choice between 4 and 6 mm2. The 4mm2 for a 15 Amp is not thick enough. Victron itself advises 1 mm2 for every 3 amps, so 5 mm2 is the minimum. Therefore the electrician went for 6 mm2, but the 6 mm2 plus the shoe is not going to fit in that terminal block.
Now why did I use a 100 / 15 MPPT controller and not a 100/30 ?
Also that is simple, they only had 4 x 100 / 30 and I needed 5. Delivery times were way too long, so had to go with the 100 / 15 and then you get a smaller terminal block.

This type of terminal block will work fine in a house, but in a boat or RV, where you have a lot of vibrations you run the chance that the screw will just unscrew itself due to the vibrations. After the first fire I got into the habit of tightening up the screws each month, so a 4 week interval. Now I was at 3 weeks, but after 50 hours of running in pretty heavy seas. The vibrations have been more than on a normal, calm, sea and that should not cause the screws to loosen up.
I am asking myself why a nut and bolt are not being used, those won't come loose or, if they don't want to go that route, simply use the block of a 100 / 30 controller. Thicker wires will fit in there and especially in countries where you cannot get all the correct equipment you basically have to do with what is available.

Victron can also choose to sell the correct cable with the controller, like e.g. Raymarine does with the radars. That would also solve the supply problem.
Btw, this installation was done by an official installer, not by me personally. I am just the end user and find myself in dangerous situations. Not because the installer wanted to cut corners, but more because the correct equipment is not available in this part of Europe.
The representative went so far to tell me I should bring the boat to a country where good installations companies and supplies could be found.

 

[Mambo42]

I'm going to rant in another direction.
Yes they are standard to the industry. The electronics industry. They were not developed with the marine environment even a consideration. They are simply an off the shelf assembly component.
The crimp pin is a questionable solution if heavy strand wire is already in place. A step up is to add a terminal strip or individual sealing crimp connectors with short jumpers of the proper sized fine strand wire as the final connection to the green strip. Most install literature cautions against both the pin and soldered wire ends leaving this the only alternative short of replacing the entire existing wiring run which becomes the best choice by default.

I never thought about it before, but after the first fire I already started asking myself why a not more permanent connection was used. This connection is obvious safe for houses and other non moveable installations. Boats and RV's however are a different story, they do move, they vibrate, they deal with non standard situations, so one would expect a design that is 100 % safe in that environment. Anything that can come loose due to vibrations and then can cause is fire is not a safe design. That is, what I call, a flawed design. Problem is you will only find out when it goes wrong, before that time you don't realize the problem.

In addition we have the problem of supply. Croatia, Greece, Turkey, Montenegro, Albania are not the same as the US or even the Netherlands where you can walk into any store and find whatever it is you need. Most of the time I am looking at long delivery times and then we are not talking days. We are talking weeks or even months or a supplier will only order something if I order many more of the same product. E.g. if I need 10 mtr cable and they don't carry that item I am forced to buy a complete roll of 50 or 100 mtrs.
Those supply problems should not be my concern, that should be the concern of the producer, they need to address that or they should not offer their equipment in that country or...........they should make it possible to use more standard wires, cable shoes etc
As an example, the Victron batteries take a 70 mm2 8 mm shoe, but those shoes are not sold in these countries. You can get a 70 mm2 10 mm shoe, but that is not the correct shoe for the battery. I have searched for these shoes in 5 countries, could not be delivered. In the end I had to buy them in a specialized shop in the Netherlands, because also there these shoes are non standard. That makes me wonder what the point is of using sizes and dimensions that are so difficult to find ? Protect your product ? Make sure that nobody will copy it ?
To me that is the wrong approach.

 

[Mambo42]

Mambo42, thanks for being brave enough to post this issue. A lot of readers will silently learn from this event.

Poor connections is the number one cause of boat fires.

I agree and I now had it twice happen to me that I almost had a fire that destroyed my boat. This time I was lucky I was onboard since the admiral would not have had any idea how to stop the supply of the solar panels to the MPPT controller.
Have we come to the point where every person onboard needs to know all the ins and outs of every piece of equipment onboard ? That cannot be the case.

What I am most surprised about is how easy these screws can loosen up due to vibrations in the boat. None of my other connections loosen up. Not the batteries, not the navigation equipment, lights, nothing. But every month I need to check the connections of all cables to the chargers, MPPT controllers, DC converters etc. It should not be necessary to do that every month, there has to be a better way.
When you design equipment you either design it for a specific market and in that case you also only make it available to that specific market or you design it in such a way that it is safe, even if the specific connectors etc are not available in a location.

I rewired the whole boat for the sole purpose to be safe onboard, to not have to deal with 45 year old cables that were falling apart. And yet I have had more fire scares than before I rewired. All of that because equipment was used for which the correct connections are not available in the countries where the equipment is sold.
But since the producer is not interested I have to come up with a solution to solve the problem, because I am not going to wait for fire nr 3 to happen.

 

[luna]

My reading of the Victron info regarding terminal size on all Smart Solar CC MPPTs up to 20 Amps is they accept 6 mm2 or Awg 10 wire.
Perhaps I’m looking at the wrong device.

5 mm2 wire seems to be an oddity in the entire EU. if it is even produced.

 

[Mambo42]

If you used the wrong size wire and did not use the shoe how is that Victron’s problem?

They or their supplier have undoubtably tested the connection and recommend to use what works.

To me it appears that you are asking Victron to do your job, properly install the product, not the other way around.

Once the shoe is installed on the wire, in so far as the connection is concerned, the number of wire strands would be irrelevant.

Many of us in the west believe that type 3 wire stranding (all strands 0.01” dia.) found in the typical Ancor boat cable is the only wire acceptable.
ABYC accepts type 2 stranding with its much larger strands for general wiring.

Looks like you need to replace the device as it’s gotten too hot. Replace the wiring as well.

Victron sells this equipment in many countries, but............the correct wiring and connectors are not being sold in those countries. Even the official Victron installers and distributors cannot get the correct wiring and connectors, so they need to improvise. And that is where the problem is.

This controller does not accept a 6 mm2 cable with a shoe that is for sale in Greece, it is not going to fit. The correct size cable is not available, cannot even order it, unless you order 50 or 100 mtrs and then you get a cable that is not suitable for maritime use.
But you have made the appointment with the yard, the electricians to deliver the boat to them so they can do the installation in the winter months.
So what are you going to do ? You will skip the whole year, leave the boat on the dry for the summer season because you have to wait for delivery of the correct sized supplies ?
Just to give you an idea, I am already waiting for more than 1 year for 5 VE direct to USB cables to connect the MPPT controllers to the Cerbo. I have ordered (and paid) them in Turkey, but they were not delivered on time. After 3 months we had to leave Turkey and the cables had not arrived.
I ordered (and paid) them again in Greece, were supposed to be delivered within 1 week, but 3 weeks later, when we had to leave, the cables had not arrived. Since then I have received a message that the cables have arrived, just one problem, we are in a completely different country, so what will I do now ? Order them again ?

The producer of the equipment is reacting from a position of an ideal situation, however reality is that this ideal situation does not exist. Certain equipment is simply not available and cannot be delivered within a reasonable period of time.

However, that is all besides the point. The main question is: 'how can I connect these cables without them loosening up all the time ?

 

[luna]

Your conductors you say are 6 mm2 and need a shoe that is not sold in Greece.

Ask Victron for their recommended shoe manufacturer, buy the shoes and the crimper from them.

Surely DHL will deliver in a few days.

Have you sourced a new device yet or are you intending to use the existing one?

 

[Mambo42]

My reading of the Victron info regarding terminal size on all Smart Solar CC MPPTs up to 20 Amps is they accept 6 mm2 or Awg 10 wire.
Perhaps I’m looking at the wrong device.

5 mm2 wire seems to be an oddity in the entire EU. if it is even produced.

This is a 15 Amp controller and according to Victron that should be a 5 mm2 cable (1 mm2 per 3 Amps). However 5 mm2 is not available and cannot be delivered, so a 6 mm2 cable was used. The Victron prescribed shoes can also not be delivered, so you have to do with something that is slightly thicker. The combination of the thicker cable and thicker shoe does not fit in this controller.

But regardless of that............why does that screw come loose ? Also in the connections where I do have the correct shoes the screw still comes loose. I need to tighten them up every month. If they come loose before that time (like it did now) I am looking at a fire hazard. That should not be the case. The connection should be safe at all times. It can be done, so why isn't it done ?

 

[Turtle Blues]

Sometimes see these terminal strips manufacturer installed in equipment where the wire does not fit when you calculate the required size by load and run. Necessitating either the crimp pin solution or adding relays to the system. Power to linear drives and hydraulic pumps being a primary example.
Large equipment and panels may get a yearly "tighten up" inspection, but I suspect repeated tightening of these small components may actually stretch the threads exacerbating the problem.

 

[Mambo42]

Your conductors you say are 6 mm2 and need a shoe that is not sold in Greece.

Ask Victron for their recommended shoe manufacturer, buy the shoes and the crimper from them.

Surely DHL will deliver in a few days.

Have you sourced a new device yet or are you intending to use the existing one?

What I would need for this controller is 5 mm2 cable plus the shoe Victron prescribes. That cannot be found in Greece, so what I will do now is drive to Italy and buy a 100 / 30 MPPT controller because that controller can accept the 6 mm2 plus shoe that I can get in Greece.
It is going to be a 2 day journey, but it is necessary.

However, that is still not going to solve the problem of the screws in the connector block coming loose due to the vibrations of the boat in heavy seas. So I still need to solve that problem in one way or another.

 

[DavidM]

You can take your 6 mm cable, trim off a few of the conductors so the shoe will fit and install it in a new controller.

FWIW, 5 mm is much more than you need for a 15A controller. There are lots and lots of RV installations here in the US that use 10 gauge wire which is about 2.6 mm for a 15A controller.

David

 

[Mambo42]

Your conductors you say are 6 mm2 and need a shoe that is not sold in Greece.

Ask Victron for their recommended shoe manufacturer, buy the shoes and the crimper from them.

Surely DHL will deliver in a few days.

Have you sourced a new device yet or are you intending to use the existing one?

What I would need is a 5 mm2 cable, but that I cannot find anywhere. So that is why the 6 mm2 cable came into play. That cable is suitable for maritime use and is also fire retardant (one of my demands). Although Greece has a large maritime presence you still cannot get all the necessary supplies. Sometimes you can wait 2 or 3 months for something to arrive. DHL is only an option if you are on an island where they have that service, otherwise it will go to Athens and you can pick it up there. Sounds nice, but if you are not anywhere close to Athens that is not going to happen.
Recently I had a fuel pump problem, had to send it to the Netherlands for repair. That took almost 3 weeks and 1000 euro in shipping cost.

But the main question will always remain: 'why do these screws in the connection block' loosen themselves, even if you have used a cable with a shoe ?

 

[Mambo42]

You can take your 6 mm cable, trim off a few of the conductors so the shoe will fit and install it in a new controller.

FWIW, 5 mm is much more than you need for a 15A controller. There are lots and lots of RV installations here in the US that use 10 gauge wire which is about 2.6 mm for a 15A controller.

David

It is Victron themselves who prescribe to use 1 mm2 for every 3 Amps. If you use a lighter cable they will claim you used the wrong cable.
The electricians used all the prescribed equipment that they could find to make this installation. Unfortunately not everything is available and thus they need to improvise. However, why do these screws loosen up, even when cable with shoe is used ? That should simply not be possible. Twice it was the cause for a beginning fire and every month I can at least tighten up 1 or 2 screws. To me that looks like a flawed design. Nice for a house, but not for use on a boat, unless you start prescribing the maximum sea state the boat can be in.

 

[Mambo42]

Hi Mambo,
obviously the cables are not properly sized and should go deeper into the terminal.
To be on the safe side i would suggest to use a controller that could accept more current, so the terminals would not be the problem in this case.
I have two solar arrays, one 940 Watts and the other 650 Watts, both 12 Volt and each parallel wired, so there is plenty of current. I use two Victron Mppt's 150/70 wired with 35 mm2 cable.
There is no need for using cable shoes as Victrons terminals have an intermediate metal plate between the screw and the shell so the strands wouldn't be harmed.
In addition i'm using an infrared camera on my smartphone to check temperatures from time to time.
So far no problems at all.

I needed 5 x 100 / 30 MPPT controllers, but at the time the supplier only had 4, so a 100 / 15 was used for a stand alone panel. Since this one is gone I will now try to find a 100 / 30 controller, have to go to Italy for that and hope they have it.

The 100 / 15 controller is limited in the size of cable you can use. A 5 mm2 cable is what Victron prescribes, but that cable is not sold in these countries, so therefore a 6 mm2 cable was used.
My problem is that the screws holding down the cables tend to come loose all the time. Every month I need to tighten them up (not all of them, but at least one or two). So I need to find a solution to ensure these screws don't loosen up anymore. 2 starting fires is enough for me.

 

[psneeld]

Lots of electrical equipment I have installed could use a slightly smaller diameter wire. In a pinch, I have trimmed off a few strands till it fits and never have had a problem unless the retaining screw or the whole set up was an issue. Usually discovered at install.

The piece of electric equipment doesn't know if a few strands were left out, especially if all was snugged to specs and the wire properly supported.

Not suggesting reducing the wire size significantly, probably more than 25% would be unwise and the more strands in the wire the better.

 

[Gypsy Island]

This is a 15 Amp controller and according to Victron that should be a 5 mm2 cable (1 mm2 per 3 Amps). However 5 mm2 is not available and cannot be delivered, so a 6 mm2 cable was used. The Victron prescribed shoes can also not be delivered, so you have to do with something that is slightly thicker. The combination of the thicker cable and thicker shoe does not fit in this controller.

But regardless of that............why does that screw come loose ? Also in the connections where I do have the correct shoes the screw still comes loose. I need to tighten them up every month. If they come loose before that time (like it did now) I am looking at a fire hazard. That should not be the case. The connection should be safe at all times. It can be done, so why isn't it done ?

I think the cable with the wrong amount of strands is the culprit. As there is not enough surface to Support the current, the copper is getting hot and soft. So the screw is not really loosening itself, the wire is literally getting soft.
I would go one or two sizes up with your controllers and use an apropriate cable just to be safe in the future.
Again use a Infrared camera to determine hot cables and connections. This money is well spent.

 

[ksanders]

Kevin - can you provide more information please? When you say add a proper sized terminal to the conductor, are referring to the ferrule setup shown in Bmarlers post #6? Or an interim terminal block to step-down size suggested in post #8? I don't recall exactly, but this is a fairly common issue I've encountered with Victron devices such as MPPT controllers or DC-DC chargers. Terminals are sized for #8 conductor (I don't remember exactly - might be #6) but given the amperage and use (meaning distance between the end points) often requires heavier cable at 12v.

What is the proper way to transition large conductor size down to a smaller terminal connection?

Thanks in advance

Peter

The most correct answer would be to use the correct size wire in the first place.
I have 30 amp charge controllers for example. 10 AWG is perfect for 30 amp circuits, and i have found that the Victron equipment accepts the correct size cables for the currents involved.

In the OP's situation there are several acceptable methods. One would be to use a terminal on the end of the wirte that would fit in the terminal. No problem with that at all.

Another solution would be a in line splice. I do not like butt splices but they work and we use them all the time in the electrical industry.

Another solution would be a terminal block interfacing the two wire sizes. I like that solution a lot but it takes real estate.

 

[Mambo42]

I think the cable with the wrong amount of strands is the culprit. As there is not enough surface to Support the current, the copper is getting hot and soft. So the screw is not really loosening itself, the wire is literally getting soft.
I would go one or two sizes up with your controllers and use an apropriate cable just to be safe in the future.
Again use a Infrared camera to determine hot cables and connections. This money is well spent.

Those kind of cables are not available in Greece. What you can get are the standard domestic cables, for households, but not usable in the maritime world. The salt air would corrode them in no time, leading to exactly the same problems.
Again, the problem was not the dimensions of the cables, the problem was (and is) that the screws are loosening up, also on the cables that do have a shoe attached to it, those are also loosening up continuously.
Unfortunately I don't have the space to add more equipment and more cables, I am severely space limited due to the fact that I have a lot of equipment installed in my boat.

Like I stated before, the only reason why I had 1 x 100 / 15 MPPT was that the 100 /30 was not available. If the fifth one would have been available I would not have bought the 100 / 15, but those were the circumstances. Now that this one has burned out I will try to source a 100 / 30 MPPT controller, but that is a bit of a challenge.

Just for your info, all the equipment was working fine, temperatures were always OK, also on the other MPPT controllers, the cables are hand warm. Only when the screws come loose does the temperature rise and in this case the wire did not melt, it was only the MPPT controller that started to melt.