polyswitch bd280 resettable fuse

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Forum Name: General Discussion
Forum Discription: General Mobile Electronics Questions and Answers
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=107179
Printed Date: May 14, 2025 at 11:27 AM

Topic: polyswitch bd280 resettable fuse

Posted By: livehho
Subject: polyswitch bd280 resettable fuse
Date Posted: September 02, 2008 at 3:29 PM

I need a 30A resettable fuse that resets automatically so I don't have to open the hood each time the fuse latches.

I was thinking of the PolySwitch BD280 resettable fuse but in the tech document is says:

"The device remains in its latched (high resistance) state until the fault
is cleared and power to the circuit is cycled â€“ restoring the
PolySwitch device to a low resistance state in the circuit and the
affected equipment to normal operating conditions."

source: https://www.tycoelectronics.com/about...ws.asp?ID=1359

So I would have to cycle the power (turn off power completely) to the circuit in order to the fuse to reset itself?

If so, then this wouldn't be a fully automatic resettable fuse? right?

Any suggestions?

Replies:

Posted By: Hornshockey
Date Posted: September 02, 2008 at 4:07 PM

An auto-resetting circuit breaker is usually not a good idea. If the circuit is pulling more than the wire can safely carry and the breaker is opening and resetting continually, it won't provide any real protection and will eventually either melt the wire or the switch itself. That product requires the current to be turned off so you can check the system to make sure that whatever caused the fault has been fixed.

If you're constantly blowing 30A fuses you should think about upgrading the wiring in whatever project you're working on to a larger wire that can handle the current demands you're putting on it and then putting a larger fuse or breaker on it.

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Life moves pretty fast; if you don't stop and look around once in a while; you could miss it.

Posted By: livehho
Date Posted: September 02, 2008 at 5:36 PM

thx Shockey

i can't go over 30Amps because of the specifications of the device. so i guess i would have to stay with a manual resettable fuse.

Posted By: megaman
Date Posted: September 02, 2008 at 9:35 PM

If the device is rated to run on a 30A supply and you are blowing fuses, It would be a logical conclusion that your device is not working properly.

Posted By: livehho
Date Posted: September 03, 2008 at 12:26 PM

This for an alternative energy application that I am fabricating which should not draw more than 30A from the 12V car battery since all my car devices draw approximately 70A and my alternator provides 100A.

So I wanted to limit the current draw by the generator. This can be done several ways.. using a auto-resettable fuse being one of them.

guess I would have to go with the other options

thanks for your help