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question about this breaker

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sdowney717

Well-known member
Joined
Mar 17, 2010
Messages
964
Thanks, I thought it would:thumbup:
They got some good prices.
I plan to get some 15's, 20's and a 40 amp.
 
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mrb

Well-known member
Joined
Dec 31, 2008
Messages
3,734
its a 40 amp breaker. Circuit breakers will have different voltage ratings for AC and DC. It is very important to not use a breaker above its dc rating, or use one on dc that does not have a dc rating. it could fail to trip, or it could burn up when trying to interrupt a load. the one you selected is fine for 12vdc use.
 

ddawg16

Well-known member
Joined
Jul 11, 2008
Messages
21,005
Location
S. California
MRB is VERY correct.

This is a thermal breaker vs the typical magnectic breaker.....

Thermal breakers open up when the current going through it is enough to heat up a resitive element to cause it to trip....this type is very common in aircraft....hence, the 32V max.....they pretty much work the same for both AC and DC loads....

The magnetic breaker you have at your house is AC ONLY.
 

mrb

Well-known member
Joined
Dec 31, 2008
Messages
3,734
MRB is VERY correct.

This is a thermal breaker vs the typical magnectic breaker.....

Thermal breakers open up when the current going through it is enough to heat up a resitive element to cause it to trip....this type is very common in aircraft....hence, the 32V max.....they pretty much work the same for both AC and DC loads....

The magnetic breaker you have at your house is AC ONLY.

thermal only breakers are not as accurate as anything magnetic and they cannot clear a fault as fast as a magnetic breaker.

house breakers are thermal - magnetic. These use the magnetic portion for the instant trip (short circuit or huge overload) and the thermal portion for time delay (to allow motors to start, inrush from appliances, things like that)

magnetic only breakers are instant trip with no time delay and are used only in special applications.

there are hydraulic magnetic breakers. these are great as they are very precise (they use a small magnetically driven hydraulic piston to provide time delay) and unlike anything with a thermal element are unaffected by ambient temperature.

the issue with DC is the arc when the contact opens is not self extinguishing like AC is. a larger contact gap is required as well as some other tricks such as using magnetic field to pull the arc sideways to increase its length are used.

bottom line, is whatever electrical equipment you are using -make sure its rated for your intended use.
 
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