Fuse Total I2t as per IEC 60269-2 1

[healyx]

Hi All,

I don't have access to IEC 60269-2. Can anyone tell me if the standard provides total I^2t energy maximum values for the various fuse types. I have IEC 60269-1 but it only specifies minimum pre-arcing energies, I need the total energies.

Cheers,

Healyx

 

[7anoter4]

At first it seems to me total I^2t energy maximum values= maximum operating I^2*t values are shown here[in IEC 60269-2-1].
However, according to IEC 60269-1 ch2.3.11 :
"operating time=sum of the pre-arcing time and the arcing time"[total time].
ch. 2.3.12 I^2*t (Joule integral):
"NOTE 1 -The pre-arcing I^2* t is the I^2* t integral extended over the pre-arcing time of the fuse.
NOTE 2 -The operating I^2* t is the I^2* t integral extended over the operating time of the fuse."
From IEC 60269-2-1 ch. 7.7 I^2* t characteristics.:
"For the fuse-links covered by this section the maximum pre-arcing I^2*t values given in Table VI(6) of IEC 60269-1 apply for the maximum operating I^2*t values."
[IEC 60269-1 Table 6 – "Pre-arcing í2t values at 0,01 s for "gG" and "gM" fuse-links"- column no.3 I^2*tmax].
"Values for rated currents lower than 16 A are given below in Table VI[from IEC 60269-2-1]."

 

[healyx]

Thanks 7antoer4.

Ch 7.7 in 60269-2 is repeated in each section isn't it? So is that note ("For the fuse-links covered by this section the maximum pre-arcing I^2*t values given in Table VI(6) of IEC 60269-1 apply for the maximum operating I^2*t values.") repeated for each section (fuse type).

I have found at least one NH fuse type where the operating I^2t is higher than those values shown in table 6.

E.g. a SIBA NH Size 1 100A gG fuse has 88.6 x 10^3 at 440v and 97 x 10^3 at 500V for total I^2t let-through, both of which are higher than the 86 x 10^3 limit in table 6. The fuse complies with the standard. How can this be?

 

[7anoter4]

In IEC 60269-2-1 it is presented:
Section I Table VI for "gG" fuses[up to 16 A].
Section V Table VI for "gD" and "gN" fuses [from 10 to 6000 A].
Section VI Table MM for "gU" fuses[from 100 to 630 A].
Since IEC 60269-1 ch.7.7 states:
"The operating I2t values verified according to 8.7 shall be less than, or equal to, the characteristics stated by the manufacturer in accordance with 5.8.2 or specified in subsequent parts.", then I think the value shown in Table 6 as I^2tmax could be less than
manufacturer specified.