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Glass Tube Fuse Identification

Tim Griffin

Oct 27, 2015
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Oct 27, 2015
Messages
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Hi all;

I have a glass tube fuse with the markings 250V 3/3 1A on it.

Could someone enlighten me as to what the "3/3" designation means?

Many thanks,
Tim
 

shrtrnd

Jan 15, 2010
3,876
Joined
Jan 15, 2010
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3,876
I don't have the information at my fingertips, but it will designate the physical size of the fuse.
There are a lot of different physical packages for fuses, and that is supposed to identify the type you have.
 

Tim Griffin

Oct 27, 2015
2
Joined
Oct 27, 2015
Messages
2
Ah, okay. Is there a way I know whether the fuse is a fast-blow or slow-blow fuse?

Tim
 

shrtrnd

Jan 15, 2010
3,876
Joined
Jan 15, 2010
Messages
3,876
Have you got a manufacturer logo on the fuse? The Littelfuse or Bussmann logo, or whomever made it?
That'll tell you exactly were to look for what the '3/3' denotes.
In simple terms, (that may not always hold true?):
A fast blow fuse is a single element, one, fine-wire element ( in a 1 amp fuse).
A slo-blo fuse will be a wire wrapped around a ceramic element (to take the heat, allowing time for a slower blow), or could be a spring-loaded element with many different appearances, depending on mfgr; or a variety of
other appearances depending on who made it.
 
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