[Mike Betts]

Originally Posted by jgw

Al:

Where does circuit protection factor into this? Individual Jags are protected by breakers at 40A max. How can 133A continue "over an extended amount of time" without something tripping?

Similarly, the main breaker on the bot is rated at 120A. Two or 4 jags in this situation should equal 266 or more amps. Why no tripping there?

JW

JW,

If you look at the spec sheet for the MX5-A40, you can pull 133A through the circuit breaker for about 3 seconds before it trips. This can be a long time for a resistor to gain heat depending on the thermal resistance of the resistor.

Add to this that the MX5-A40 is an auto-resetting CB meaning that the heating can be cumulative as it repeatedly trips and resets.

Likewise, the 120A can pull much more than 266A for quite a long time...

Regards,

Mike

Edit: I had to back a couple of years to get a spec sheet on the 120A CB but you can see that it can pull 266A for over 20 seconds...