tuesdays 2391 20 question

[gamblor6]

a 6mm copper conductor, 70 degrees, protected by a 45a 1361 fuse, with a fault current of 240a, will the fuse trip in time to protect the cable?

 

[Sparky Ninja]

Are you asking the question? or giving us the question?

 

[gamblor6]

both lol. iaswered. wanna see what happen on here.

 

[Sparky Ninja]

I get a duration time of 8.3 seconds, with a disconnection time of 5.

So my answer would be yes.

 

[gamblor6]

i got 12 sec with the disconnection time (sic)6 sec. so yes. just thought id put it out there.

 

[gamblor6]

lol i also used your duration value analagee for the earthing question. i hope your right lol.

 

[Sparky Ninja]

What was the earthing question?

 

[gamblor6]

cant really remember, state the diff between main bonding and supp i think, the brain gets sketchy after 4 days an some beers lol

 

[pushrod]

i got 12 sec with the disconnection time (sic)6 sec. so yes. just thought id put it out there.

S=6mm
K=115
I=240A
duration time t = (S² * k²)/I²
=8.3s

My money is on widdler

 

[gamblor6]

i made k as 148 other than that im the same

 

[Sparky Ninja]

i made k as 148 other than that im the same

where from?

 

[pushrod]

where from?

Must admit i wondered that as the value of 148 isn't even an option in the brb table i looked at.

 

[gamblor6]

143 sorry. didnt have my book to hand earlier. table 54.2

 

[Sparky Ninja]

Would have been better to use Table 43.1

 

[gamblor6]

the question didnt state that the conductor was bunched. i thought it best to assume not or it would have said.