Over Current Protection

[Gona]

Dear Sylvi,

Are there any DC protection devices (other than fuses) to cut off the circuit in case of a short circuit condition? (similar to RCCB in AC circuits)

[Sylvi]

  On 9/24/2012 at 4:50 AM, Gona said:

Dear Sylvi,

Are there any DC protection devices (other than fuses) to cut off the circuit in case of a short circuit condition? (similar to RCCB in AC circuits)

I had one vehicle fitted with 62 ampere AC circuit fitted on the line only It worked for a over load very well.

Some have electrically operated switches for this type of operation old Oil transport tankers had this on their 24DC volts system.

If any member wants can fabricate one in Srilanka. Cost have to it and give.

If you want one, can buy from USA I will give the web link under.

http://www.solar-electric.com/mr60ampdccib.html

Sylvi Wijesinghe.

[Sylvi]

Members,

The under is not on to the topic. Because this subject had come up on this thread. One member requested for safety on dc protection, I post on same.

I did not mention correctly of fitting the AC circuit breakers single pole on to a DC circuit from the time said units were imported to our country about 40 years ago. I have done this AC circuit breakers fitting on to DC different voltage circuits.

That modification was very successful on over amperage in low dc circuits’ protection.

Because above circuit breakers are thermal Circuit Breakers: These breakers employ heat to break the circuit current flow and consist of a bimetallic strip, made of two types of materials welded together. At high heat levels, produced on higher amperages rated more than the circuit barker, this strip bends at an angle due bimetallic strip two metallic expansions are different to each other, that pulls the lever down and breaks the connection between the circuit breakers contact plate and the stationary contact plate.

As for automobiles this should be connect on the main accessory supply line not on Starter motor supply line. Because self starter motors draw very high current (Amperes) during the engine start operation.

Most wire failures and short circuits occur on the accessory supply line due to short circuit a fire can start in an automobile. The over amperage cutoff breaker will prevent that.

If not the breaker can be operated by the driver as on his notice a smell of heated insulated wire or smoke. This will prevent a total disaster on the car. First he should do is to off the engine next off the circuit breaker.

This breaker can be fitted by testing with an Amperage meter to check what is the total discharge, of amperage on the vehicle with all accessories on and giving a small additional amperage margin for safety of operation.

If not the entire load amperage is on the circuit breaker will operate by shutting down.

Above is my successful experience in AC thermal Circuit Breakers fixing on DC wiring circuits.

Some members will not agree and they will give different opinions’ on above.

Sylvi Wijesinghe.

[Gona]

  On 9/25/2012 at 3:54 AM, Sylvi said:

Members,

The under is not on to the topic. Because this subject had come up on this thread. One member requested for safety on dc protection, I post on same.

I did not mention correctly of fitting the AC circuit breakers single pole on to a DC circuit from the time said units were imported to our country about 40 years ago. I have done this AC circuit breakers fitting on to DC different voltage circuits.

That modification was very successful on over amperage in low dc circuits’ protection.

Because above circuit breakers are thermal Circuit Breakers: These breakers employ heat to break the circuit current flow and consist of a bimetallic strip, made of two types of materials welded together. At high heat levels, produced on higher amperages rated more than the circuit barker, this strip bends at an angle due bimetallic strip two metallic expansions are different to each other, that pulls the lever down and breaks the connection between the circuit breakers contact plate and the stationary contact plate.

As for automobiles this should be connect on the main accessory supply line not on Starter motor supply line. Because self starter motors draw very high current (Amperes) during the engine start operation.

Most wire failures and short circuits occur on the accessory supply line due to short circuit a fire can start in an automobile. The over amperage cutoff breaker will prevent that.

If not the breaker can be operated by the driver as on his notice a smell of heated insulated wire or smoke. This will prevent a total disaster on the car. First he should do is to off the engine next off the circuit breaker.

This breaker can be fitted by testing with an Amperage meter to check what is the total discharge, of amperage on the vehicle with all accessories on and giving a small additional amperage margin for safety of operation.

If not the entire load amperage is on the circuit breaker will operate by shutting down.

Above is my successful experience in AC thermal Circuit Breakers fixing on DC wiring circuits.

Some members will not agree and they will give different opinions’ on above.

Sylvi Wijesinghe.

Thank You,

This is what I understood.

The DC circuit breaker is capable only to cut off sustaining thermal overload currents.

The DC circuit breaker is not capable of tripping off instantaneous short circuit currents

Based on above facts I derive that it can be used as an extra protection device to cut off the power supply of the main accessory supply line to prevent an electrical fire

One more question.

As per your experience; what is the reason for majority of the automobile fires due to electrical system faults? Is it due to sustaining overloads or instantaneous over current?

Thanks in advance

[Watchman]

  On 9/25/2012 at 6:22 AM, Gona said:

Thank You,

This is what I understood.The DC circuit breaker is capable only to cut off sustaining thermal overload currents.The DC circuit breaker is not capable of tripping off instantaneous short circuit currents

Based on above facts I derive that it can be used as an extra protection device to cut off the power supply of the main accessory supply line to prevent an electrical fire

One more question.

As per your experience; what is the reason for majority of the automobile fires due to electrical system faults? Is it due to sustaining overloads or instantaneous over current?

Thanks in advance

I dont know about you but I wouldnt try tapping into or cutting factory fitted wires as sylvi mentioned. If Automotive manufacturers saw a necessity for it they would do it themselves. Frankly Even if there IS an electrical fire in your car and you have such a sylvi-switch installed, turning the switch off wont put out the fire that's already started. And all these home-made wiring only creates more potential electrical accidents.

And Gona, if I were you I would really take Sylvi's advice with great caution..

Edited September 25, 2012 by Watchman

[Sylvi]

  On 9/25/2012 at 6:22 AM, Gona said:

Thank You,

This is what I understood.

The DC circuit breaker is capable only to cut off sustaining thermal overload currents.

The DC circuit breaker is not capable of tripping off instantaneous short circuit currents

Based on above facts I derive that it can be used as an extra protection device to cut off the power supply of the main accessory supply line to prevent an electrical fire

One more question.

As per your experience; what is the reason for majority of the automobile fires due to electrical system faults? Is it due to sustaining overloads or instantaneous over current?

Thanks in advance

'Gona'

It is a very good question you have requested to reply.

About your question of tripping off instantaneous short circuit currents. I will do a practical test and inform to the forum about the result. Give me little time for that. Only have had the experience of over amperage tripping. When ever I do a DC wiring as for my earlier post I do amperage test and leave a small margin for safety operation.

About last Question.

1. Normally electrical fires start due to short circuits. This means wire insulation failure can touch to any body part of the vehicle which do not have a fusing arrangement mostly on power leads to main wiring harness. At that point the wire get like arc welded. Next is wire insulation failure to over load of amperes if the wire line is not protected by a fuse get overheated and catch fire when the temperature reaches the insulation flashing point. Before that smell and then followed by fire.

I have noticed most all new vehicles have large fuses on power leads.

2. Fires not due to electrical problems are mainly the fuel lines wherever they have rubber connectors perishing and due to pump pressure fuel get flashed on to heated exhaust system where flashing point of that fuel is sufficient then will get ignited.

3. Most vehicle fires starts on the vehicle on driving other than above. During a accident which fuel tanks can catch fire due to the impact.

Above is my opinion.

Sylvi Wijesinghe.

[Gona]

Are there any DC protection devices (other than fuses) to cut off the circuit in case of a short circuit condition? (similar to RCCB in AC circuits)

[Sylvi]

Members,

There are few posts criticizing my posts on the previous thread I do not care for them I will write my practical experiences in future too.

In mostly electrical systems of AC AND DC Voltage questions come up on the forum. Within my knowledge.

Sylvi Wijesinghe.

[Sylvi]

  On 9/25/2012 at 10:44 AM, Gona said:

Are there any DC protection devices (other than fuses) to cut off the circuit in case of a short circuit condition? (similar to RCCB in AC circuits)

'Gona',

Please refer to this web page under.

http://bluesea.com/viewresource/98

Sylvi Wijesinghe.

[Watchman]

Gona,

In the name of being factual (and warning future readers of this thread) let me point out WHY you shouldnt be doing something like this. I mentioned this in the other thread but i think post got misplaced in the migration to the new thread (maybe a mod can look into it if its not too much trouble).

Imagine the PVC pipe that brings water from your overhead tank to your house. In the middle there's going to be joints and taps etc right? Now think about all the places that water leaks from, in this system. Its normally always from the joints and taps. If it's a tap you NEED then you have to live with it. But you dont cut a perfectly fine pipe and put a joint in the middle for no reason right?

Likewise you shouldnt be cutting and chopping a vehicle's wiring unless its absolutely necessary. Every time you expose a live wire you're creating a potential risk of water seeping into it and shorting out, or the insulation you used getting undone and shorting out or even the switch/device you use failing and creating a fire. And this sylvi-switch is like closing the stable-gate after the horse has escaped. It won't prevent an electrical fire. Car manufacturers who have more experience than sylvi have designed fuses and relays to minimize leaks, to minimize the current that flows in wires and and to blow a fuse in case there IS a leak..

Sylvi's hobby is to experiment with his vehicles till they are destroyed. If you dont believe me ask him what happened to the brand new van he bought a few years ago..In the end he replaced so many parts that were burnt out or broke down. Sylvi always brags that his father left him a lot of wealth to do all sorts fo crazy stuff with. So we're ok with it because its his money... But if you follow his bad advice and fail, he wont replace your vehicle if it burns to the ground or worse replace a loved one who died in a electrical fire caused by you trying out sylvi's experiments.

So leave the electrical system alone and dont try to modify it on your own. If there's a repair needed goto a qualified and knowledgeable electrician. And remember a mature knowledgeable person wont brag or boast about his experience or knowledge.

[Gona]

  On 9/25/2012 at 2:29 PM, Watchman said:

Gona,

In the name of being factual (and warning future readers of this thread) let me point out WHY you shouldnt be doing something like this. I mentioned this in the other thread but i think post got misplaced in the migration to the new thread (maybe a mod can look into it if its not too much trouble).

Imagine the PVC pipe that brings water from your overhead tank to your house. In the middle there's going to be joints and taps etc right? Now think about all the places that water leaks from, in this system. Its normally always from the joints and taps. If it's a tap you NEED then you have to live with it. But you dont cut a perfectly fine pipe and put a joint in the middle for no reason right?

Likewise you shouldnt be cutting and chopping a vehicle's wiring unless its absolutely necessary. Every time you expose a live wire you're creating a potential risk of water seeping into it and shorting out, or the insulation you used getting undone and shorting out or even the switch/device you use failing and creating a fire. And this sylvi-switch is like closing the stable-gate after the horse has escaped. It won't prevent an electrical fire. Car manufacturers who have more experience than sylvi have designed fuses and relays to minimize leaks, to minimize the current that flows in wires and and to blow a fuse in case there IS a leak..

Sylvi's hobby is to experiment with his vehicles till they are destroyed. If you dont believe me ask him what happened to the brand new van he bought a few years ago..In the end he replaced so many parts that were burnt out or broke down. Sylvi always brags that his father left him a lot of wealth to do all sorts fo crazy stuff with. So we're ok with it because its his money... But if you follow his bad advice and fail, he wont replace your vehicle if it burns to the ground or worse replace a loved one who died in a electrical fire caused by you trying out sylvi's experiments.

So leave the electrical system alone and dont try to modify it on your own. If there's a repair needed goto a qualified and knowledgeable electrician. And remember a mature knowledgeable person wont brag or boast about his experience or knowledge.

I honour your view on the matter

I am bit concerned about the safety side on following grounds.

I'm Using a car (Japanese) which is about 15 years old. You may aware that for domestic and industrial cabling the manufacturers advice to look for aging defect after 25 years of operation. In Automobiles the ambient conditions are different and the decaying may start at a lesser period of time.

Therefore thought that it is good to have an extra protection for the system with minimum modifications to improve the safety.

You know that high ways are coming in and, some times I may have to travel on those with my loved ones in this vehicle. So in addtion to make sure the vehicle is mechanically fit, I want to be satisfied with it's electrical condition also.

After all if the general idea of the members is; it is not worth while, I am not going to take a risk in experimenting

[XBeat]

  On 9/25/2012 at 5:12 PM, Gona said:

I honour your view on the matter

I am bit concerned about the safety side on following grounds.

I'm Using a car (Japanese) which is about 15 years old. You may aware that for domestic and industrial cabling the manufacturers advice to look for aging defect after 25 years of operation. In Automobiles the ambient conditions are different and the decaying may start at a lesser period of time.

Therefore thought that it is good to have an extra protection for the system with minimum modifications to improve the safety.

You know that high ways are coming in and, some times I may have to travel on those with my loved ones in this vehicle. So in addtion to make sure the vehicle is mechanically fit, I want to be satisfied with it's electrical condition also.

After all if the general idea of the members is; it is not worth while, I am not going to take a risk in experimenting

The extend of safety you are concerned is not necessary for regular automobiles. It might required for special purpose vehicles such as those operate in explosive atmospheres, Ships, Submarines or perhaps in space shuttles. As "Watchman" pointed out Automobile Engineers must have evaluate that risk in the design phase it self and omitted it considering the near Zero Probability of occurrence of such a fault.

The Best thing you can do is to; maintain your fuse box with the specified ratings without going for shortcuts such as replacing them with copper wires; and do what ever repairing through a good auto-electrician.

[Sylvi]

Gona,

This type of criticizing for my posts is a common thing in this forum.

This the reason I gave you few web links the unit what you was interested, which are used in the developed world for you to read.

I said in one of my posts short circuit failure on a circuit breaker let me check and come bake to the forum. I have tested the over amperage.

I gave the experience and my knowledge on to your request not to force you or any member who reads this forum to miss lead.

Only with my good intentions. Because which I done to others have have had been successful.

There are few members of the forum had come to meet me and got my personal advice,

At the moment I do a project to improve one unit of a automobile, which some members had posted negative replies.

Please note during the industrial revolution the early years, in the world the world Reputed scientists found plenty of patents by experimenting.

I was in a research and development laboratory and certified for my experience even they do experiment to materials and practices to further development for new industrial units and medical drugs for future world. After clinical trails only they putout any drugs for approved.

Like wise I do a experiment with my money and my time knowledge what I have gained over the years may be on vehicles or any other industrial units.

All modifications I have done to industry were very successful some others had followed them.

If original part is not available no owner of a vehicle or on a industrial unit will not want to throw prematurely failed said ones.

Go in for a entirely new Vehicle or a Industrial unit which they have spend lot of money so they try to do some modification for same.

So others should not get any animosity for explaining them to the forum if they like take same or leave it.

Sylvi Wijesinghe.

[Watchman]

  On 9/25/2012 at 5:12 PM, Gona said:

I'm Using a car (Japanese) which is about 15 years old. You may aware that for domestic and industrial cabling the manufacturers advice to look for aging defect after 25 years of operation. In Automobiles the ambient conditions are different and the decaying may start at a lesser period of time.

Therefore thought that it is good to have an extra protection for the system with minimum modifications to improve the safety.

You know that high ways are coming in and, some times I may have to travel on those with my loved ones in this vehicle. So in addtion to make sure the vehicle is mechanically fit, I want to be satisfied with it's electrical condition also.

Point 1:

I agree wires (at least the plastic covering on the wires) do decay with time. The only way to get around is to replace all the wiring. But that's a lot of unnecessary hassle/cost. If you see that the plastic coating on some wire has started to decay replace that entire wire. Dont cut out just the decayed part and try to restore that part.. And adding a master switch wont help at all! That's because you cant run the vehicle with the electrical system turned off, and turning it off as soon as the vehicle catches fire also wont put out the fire. And if there's a electrical current leak the first thing that will happen is that the fuse will blow and cut off the electricity to that component.

Part2:

In my opinion the highway shouldnt be any different from any other road if you drive within the vehicle's capabilities.

In summary, just make sure your vehicle is well maintained. Whatever problems that you foresee will turn up in your maintenance checks and you can fix it before its too late.

[Watchman]

  On 9/26/2012 at 2:25 AM, Sylvi said:

Gona,

[Point 1]This type of criticizing for my posts is a common thing in this forum.

This the reason I gave you few web links the unit what you was interested, which are used in the developed world for you to read.

I said in one of my posts short circuit failure on a circuit breaker let me check and come bake to the forum. I have tested the over amperage.

[Point 2]I gave the experience and my knowledge on to your request not to force you or any member who reads this forum to miss lead.

Only with my good intentions. Because which I done to others have have had been successful.

There are few members of the forum had come to meet me and got my personal advice,

[Point 3]At the moment I do a project to improve one unit of a automobile, which some members had posted negative replies.

[Point 4]Please note during the industrial revolution the early years, in the world the world Reputed scientists found plenty of patents by experimenting.

[Point 5]I was in a research and development laboratory and certified for my experience even they do experiment to materials and practices to further development for new industrial units and medical drugs for future world. After clinical trails only they putout any drugs for approved.

Like wise I do a experiment with my money and my time knowledge what I have gained over the years may be on vehicles or any other industrial units.

All modifications I have done to industry were very successful some others had followed them.

[Point 6]If original part is not available no owner of a vehicle or on a industrial unit will not want to throw prematurely failed said ones.

Go in for a entirely new Vehicle or a Industrial unit which they have spend lot of money so they try to do some modification for same.

So others should not get any animosity for explaining them to the forum if they like take same or leave it.

Sylvi Wijesinghe.

Point1: If so many people criticize you dont you think there MIGHT be something wrong with you and your advice?

Point 2: We dont deny that you have 50 years of windscreen-washing experience. But we challenge your knowledge of modern automotive technology. And frankly I would think that someone with with the knowledge gained through 50 years of experience in ANY field would rise to become a prominent figure in his field. But you havent.. Which goes to say how incompetent you are to begin with. So don't go around trying to deceive and cheat people by giving advice just because you have 50 years.

Point 3: Again, the reason you get negative responses is because your projects themselves are negative.

Point 4: So how many patents have YOUR experiments in your 50 years of experience gotten YOU?

Point 5: <<my comment on what drug companies used sylvi's body for has been removed upon moderator request>>

Point 6: You make no sense at all..

Edited September 26, 2012 by Watchman

[Scooter]

You go for it, Sylvi. I admire you for being prepared to think about something automotive and being prepared to get your hands dirty. Projects mightn't always be successful but I reckon you get a bit of fun and enjoyment out of it all. Next time I'm in Colombo we'll have an arrack and a bit of a natter about the good days of motoring, that's a definite.

[Sylvi]

Scooter,

Thank you for your reply post.

Welcome to my residence. Glad to have you for a discussion. Not only Arrack a meal too. Please inform early.

Sylvi Wijesinghe.

Edited September 26, 2012 by Sylvi