2 blue sea breakers pop in one day (1 Viewer)

[RFB]

Ive had two seprate 80amp breakers under the hood for 4 years. One for redarc and one for Magnum Compressor. Superhot yeterday and the red arc popped didnt want to reset, Then today again very hot out Compressor kept tripping while airing up. is this a thing? Swapped in new redarc breaker on side of road aall is well Swapping in new Breaker for Compressor and expecting same. But Does the heat or age finally KO these things??

 

[smritte]

The way breakers work is like this, two different pieces of metal made into a strip. When current starts to reach max for the size of the metal, it gets hot. Once this happens the two different metals expand at different rates and the bar bends at one end. This breaks contact. The auto reset ones bend back when they cool and the manual reset have to be "clicked" back.
So...they operate with heat and can get weaker if they have been tripped a bunch. I guess its possible the extra heat could have effected it but I think that's reaching a bit. I do know electrical items can get weaker with age.
Add those together and a definite maybe.
Remember, never say cant happen.

 

[smritte]

Forgot, the heat will make your compressor draw more. Also motors will draw more with age. This is probably more of a factor.
My work with auto air conditioning blower motors was, the average new one draws around 12 amps. Years later that same motor can be drawing 20 amps. It runs the same and you see nothing wrong but it burns out controllers and melts terminals.

 

[RFB]

great info, thanks. What I did discover was the old redarc was a 25 and I had a 30amp break on it. the new one is 50 and i did not swap in a larger breaker ( i have now)

 

[Comet]

Check your connections. Heat will also build up with age due to corrosion.

 

[RFB]

Check your connections. Heat will also build up with age due to corrosion.

Oh im on it, changed all wring out already.

 

[Azca]

The way breakers work is like this, two different pieces of metal made into a strip. When current starts to reach max for the size of the metal, it gets hot. Once this happens the two different metals expand at different rates and the bar bends at one end. This breaks contact. The auto reset ones bend back when they cool and the manual reset have to be "clicked" back.
So...they operate with heat and can get weaker if they have been tripped a bunch. I guess its possible the extra heat could have effected it but I think that's reaching a bit. I do know electrical items can get weaker with age.
Add those together and a definite maybe.
Remember, never say cant happen.

Absolutely correct. These, if they are the blue sea system CBs are inverse time and incorporate two different trip mechanisms. The first, as indicated above, are probably bi-metallic strips (could be a solder pot). The second works with "high magnitude" shorts or faults. Inverse time means: The larger the current flow, the quicker the unit opens. Inverse time CBs allow motors to start and will not trip under "temporary" overloads.

When tripping due to an overload, the metal has to cool so it can harden or return to its original position. When a breaker gets heat soaked, it can take some time for this to happen. It will not reset (relatch may be a better way to look at it) until it has returned or hardened to the point it can support the load offered by the spring used to keep tension on it.

Manufacturers publish temperature curves for their breakers that show how temperatures "de-rate" the current carrying capability. Generally, the larger the breaker, the more this impacts the unit. One example is shown below for a Square D, QO style breaker. Breakers used in the building industry are generally rated for use at 40C, hence the heavy line. (Sorry for the cut off, I used this as an example in some of my seminars). You would have to consult with the manufacturer to verify what their curves look like.

You may want to bump up your breaker size, cautiously. If your wire is still protected by the larger breaker and you have properly protected all the loads after you split them at the terminal box, you should be okay. Again, be cautious, I am not an expert by any stretch of the imagination, of DC vehicle systems so, please verify before doing so.

One final point. The role of the OL device is to protect the wire insulation and downstream equipment it protects, against overheating which would damage the insulation. Short or infrequent overloads will not be an issue for this. The temperature of the wire would not heat enough to cause prolonged damage. It is long duration exposure to heat, both ambient and circuit load, which are the issue (think of our wire loom at the EGR pipe).

Wire has a life expectancy. In the building industry, that is generally considered to be 30 years provided you maintain the wire in such a way as it does not exceed the conductor's insulation rating. The load and ambient heat contribute to this. You must de-rate the wire (current carrying capacity) when used in higher ambients. As an example, if you heat the conductor's insulation by 10C over its rating, you cut the life expectancy of the wire by half. This is exponentially true, if you heat it by another 10C, you decrease it by half again. I have no Idea of how conductor insulation in the automotive world is rated or what its design life expectancy is however, suffice it to say, going larger will increase the life expectancy of the conductor.

Okay, one final-final note. The wire at the circuit breaker will act like a heat sink and remove heat from the breaker changing the characteristics of the breaker. Larger wire, larger heat sink. Too small a wire will cause a breaker to open prematurely due to the heat of the conductor and the smaller heat sink. You also want to be careful of where your breaker (or fuse) is located in relation to the load it supplies. A device located in a cooler environment that supplies a load in a hot environment should be adjusted in size to compensate for the change in temperature to properly protect the wire and equipment.

 

[Azca]

Absolutely correct. These, if they are the blue sea system CBs are inverse time and incorporate two different trip mechanisms. The first, as indicated above, are probably bi-metallic strips (could be a solder pot). The second works with "high magnitude" shorts or faults. Inverse time means: The larger the current flow, the quicker the unit opens. Inverse time CBs allow motors to start and will not trip under "temporary" overloads.

When tripping due to an overload, the metal has to cool so it can harden or return to its original position. When a breaker gets heat soaked, it can take some time for this to happen. It will not reset (relatch may be a better way to look at it) until it has returned or hardened to the point it can support the load offered by the spring used to keep tension on it.

Manufacturers publish temperature curves for their breakers that show how temperatures "de-rate" the current carrying capability. Generally, the larger the breaker, the more this impacts the unit. One example is shown below for a Square D, QO style breaker. Breakers used in the building industry are generally rated for use at 40C, hence the heavy line. (Sorry for the cut off, I used this as an example in some of my seminars). You would have to consult with the manufacturer to verify what their curves look like.

You may want to bump up your breaker size, cautiously. If your wire is still protected by the larger breaker and you have properly protected all the loads after you split them at the terminal box, you should be okay. Again, be cautious, I am not an expert by any stretch of the imagination, of DC vehicle systems so, please verify before doing so.

One final point. The role of the OL device is to protect the wire insulation and downstream equipment it protects, against overheating which would damage the insulation. Short or infrequent overloads will not be an issue for this. The temperature of the wire would not heat enough to cause prolonged damage. It is long duration exposure to heat, both ambient and circuit load, which are the issue (think of our wire loom at the EGR pipe).

Wire has a life expectancy. In the building industry, that is generally considered to be 30 years provided you maintain the wire in such a way as it does not exceed the conductor's insulation rating. The load and ambient heat contribute to this. You must de-rate the wire (current carrying capacity) when used in higher ambients. As an example, if you heat the conductor's insulation by 10C over its rating, you cut the life expectancy of the wire by half. This is exponentially true, if you heat it by another 10C, you decrease it by half again. I have no Idea of how conductor insulation in the automotive world is rated or what its design life expectancy is however, suffice it to say, going larger will increase the life expectancy of the conductor.

Okay, one final-final note. The wire at the circuit breaker will act like a heat sink and remove heat from the breaker changing the characteristics of the breaker. Larger wire, larger heat sink. Too small a wire will cause a breaker to open prematurely due to the heat of the conductor and the smaller heat sink. You also want to be careful of where your breaker (or fuse) is located in relation to the load it supplies. A device located in a cooler environment that supplies a load in a hot environment should be adjusted in size to compensate for the change in temperature to properly protect the wire and equipment.

View attachment 2716082

Here is a quick screen grab of the 80A BS TCC. Sorry, didn't grab the model#. I also note that it is made by Cooper/Bussmann (Eaton). Very good manufacturer.

 

[RFB]

Absolutely correct. These, if they are the blue sea system CBs are inverse time and incorporate two different trip mechanisms. The first, as indicated above, are probably bi-metallic strips (could be a solder pot). The second works with "high magnitude" shorts or faults. Inverse time means: The larger the current flow, the quicker the unit opens. Inverse time CBs allow motors to start and will not trip under "temporary" overloads.

When tripping due to an overload, the metal has to cool so it can harden or return to its original position. When a breaker gets heat soaked, it can take some time for this to happen. It will not reset (relatch may be a better way to look at it) until it has returned or hardened to the point it can support the load offered by the spring used to keep tension on it.

Manufacturers publish temperature curves for their breakers that show how temperatures "de-rate" the current carrying capability. Generally, the larger the breaker, the more this impacts the unit. One example is shown below for a Square D, QO style breaker. Breakers used in the building industry are generally rated for use at 40C, hence the heavy line. (Sorry for the cut off, I used this as an example in some of my seminars). You would have to consult with the manufacturer to verify what their curves look like.

You may want to bump up your breaker size, cautiously. If your wire is still protected by the larger breaker and you have properly protected all the loads after you split them at the terminal box, you should be okay. Again, be cautious, I am not an expert by any stretch of the imagination, of DC vehicle systems so, please verify before doing so.

One final point. The role of the OL device is to protect the wire insulation and downstream equipment it protects, against overheating which would damage the insulation. Short or infrequent overloads will not be an issue for this. The temperature of the wire would not heat enough to cause prolonged damage. It is long duration exposure to heat, both ambient and circuit load, which are the issue (think of our wire loom at the EGR pipe).

Wire has a life expectancy. In the building industry, that is generally considered to be 30 years provided you maintain the wire in such a way as it does not exceed the conductor's insulation rating. The load and ambient heat contribute to this. You must de-rate the wire (current carrying capacity) when used in higher ambients. As an example, if you heat the conductor's insulation by 10C over its rating, you cut the life expectancy of the wire by half. This is exponentially true, if you heat it by another 10C, you decrease it by half again. I have no Idea of how conductor insulation in the automotive world is rated or what its design life expectancy is however, suffice it to say, going larger will increase the life expectancy of the conductor.

Okay, one final-final note. The wire at the circuit breaker will act like a heat sink and remove heat from the breaker changing the characteristics of the breaker. Larger wire, larger heat sink. Too small a wire will cause a breaker to open prematurely due to the heat of the conductor and the smaller heat sink. You also want to be careful of where your breaker (or fuse) is located in relation to the load it supplies. A device located in a cooler environment that supplies a load in a hot environment should be adjusted in size to compensate for the change in temperature to properly protect the wire and equipment.

View attachment 2716082

You just broke my brain, but thank you. I installed the redarc 50AMP and didnt realize I only had a blue sea 30amp breaker under hood, Because of the location its impossible to see. I think that played a part.