Cartridge fuse question

[theoldwizard1]

What is the difference between a NON and a NOS cartridge fuse ?

 

[kenfath]

Catalog Symbol: NON (250V); NOS (600V)
For general purpose application
Ampere Rating: ⁄Ω• to 600A
Voltage Rating: NON: 250Vac, 125Vdc (0-100A);
NOS: 600Vac
Non-Current-Limiting
Interrupting Rating: 50,000A RMS Sym. (0-60A),
10,000A RMS Sym. (65-600A), 50,000A @ 125Vdc (NON 0-60),
10,000A @ 125Vdc (NON 65-100A)
Agency Information:
UL Listed - 250V: Class K5 (0-60A), Std. 248-9
Class H (65-600A), Std. 248-6
(125Vdc: NON 0-100)
600V: Class K5 (0-60A), Std. 248-9
Class H (70-600A), Std. 248-6
UL Guide JDDZ, File E4274
CSA Certified, Class 1421-01, File 53787 (0-12 & 65-600A)† 250V
(0-600A) 600V

 

[theoldwizard1]

Okay, in "laymans terms", PLEASE !

I don't understand how a fuse can be "Non-Current-Limiting". I mean, isn't that the point of a fuse, to interrupt the current flow if it exceeds the rating (plus safety factor) for the specified amount of time ?

 

[sparky36000]

Current limiting has to do with the high short circuit currents that happen in the first few cycles that a fault occurs. Fault currents can reach thousands of amps in the few cycles before an overcurrent device opens. A current limiting fuse will open within the first half cycle, thus lowering the short circuit current during a fault. In laymans terms, a current limiting fuse opens faster than a non-current limiting. They will both work the same in an overload condition.

 

[theoldwizard1]

Current limiting has to do with the high short circuit currents that happen in the first few cycles that a fault occurs. Fault currents can reach thousands of amps in the few cycles before an overcurrent device opens. A current limiting fuse will open within the first half cycle, thus lowering the short circuit current during a fault. In laymans terms, a current limiting fuse opens faster than a non-current limiting. They will both work the same in an overload condition.

I always knew there were "fast blow" fuse and "slow blow" fuses, just never heard of the 3 letter terminology.

 

[sparky36000]

And NON is a 250vac fuse and NOS is a 600vac rated fuse

 

[sparky36000]

I always knew there were "fast blow" fuse and "slow blow" fuses, just never heard of the 3 letter terminology.

Time delay or "slow blow" fuses are a whole different animal . You can have time delay current limiting fuses.