what code code for DB with Ipf of 4Ka?

[justtryingtolearn]

Hi guys I really need some help on this question. semi enclosed fuses are located in a distribution board where Ipf was measured and recorded as 4ka. What code would be given during a periodic and does and what is the associated regs number for it?

THANK YOU

 

[Rockingit]

What makes you think that a value of 4kA is a danger? Also - is that a figure derived from 1ph or 3ph nominal or actual measurement? What are the withstand values on the cpd's??

I'll grant it would be an unusually high value for a standard 230v domestic but on a 3ph supply doesn't sound unreasonable at all.

 

[justtryingtolearn]

What makes you think that a value of 4kA is a danger? Also - is that a figure derived from 1ph or 3ph nominal or actual measurement? What are the withstand values on the cpd's??

I'll grant it would be an unusually high value for a standard 230v domestic but on a 3ph supply doesn't sound unreasonable at all.

Hi, I really appreciate your reply. its a single phase and a actual measurement. It's a question that's on one of my 2391 question papers and I haven't got a clue. That's actually all the information that is given.

So on a single phase would you class this as a fi code?

What makes you think that a value of 4kA is a danger? Also - is that a figure derived from 1ph or 3ph nominal or actual measurement? What are the withstand values on the cpd's??

I'll grant it would be an unusually high value for a standard 230v domestic but on a 3ph supply doesn't sound unreasonable at all.

 

[pc1966]

Reg 434.5.1 cover this.

BS 3036 can (I think) be found in 1kA, 2kA and 4kA breaking limits so all are a problem if you have a high capacity supply, though as above I suspect a PFC or PSSC of 4kA and above is quite rare in domestic boards.

The usual BS88 supply cut-out fuse might help you if it is 63A as that limits your peak current so with 4kA PFC (symmetric RMS amps) you max is 3kA peak so would be OK for a 4kA rewirable fuse, but if the supply fuse is larger it won't help. End of circuit faults ought to be OK as your R1+R2 may limit the PFC, or your 13A fuse will do it, but not for wiring faults near the DB.

Unless you know that the particular style of fuse is as high as 4kA and the supply use is 60A/63A then I would put this as C2 code as potentially dangerous.

 

[justtryingtolearn]

Reg 434.5.1 cover this.

BS 3036 can (I think) be found in 1kA, 2kA and 4kA breaking limits so all are a problem if you have a high capacity supply, though as above I suspect a PFC or PSSC of 4kA and above is quite rare in domestic boards.

The usual BS88 supply cut-out fuse might help you if it is 63A as that limits your peak current so with 4kA PFC (symmetric RMS amps) you max is 3kA peak so would be OK for a 4kA rewirable fuse, but if the supply fuse is larger it won't help. End of circuit faults ought to be OK as your R1+R2 may limit the PFC, or your 13A fuse will do it, but not for wiring faults near the DB.

Unless you know that the particular style of fuse is as high as 4kA and the supply use is 60A/63A then I would put this as C2 code as potentially dangerous.

 

[justtryingtolearn]

You honestly don't know how much I appreciate you taking time out to answer this question for me. Thank you very much.

 

[Markdpalmer]

I have been struggling with this question also, I just read that reg and seems like it fits. Fingers crossed I got it right.

 

[Obi Jon Kenobi 89]

What makes you think that a value of 4kA is a danger? Also - is that a figure derived from 1ph or 3ph nominal or actual measurement? What are the withstand values on the cpd's??

I'll grant it would be an unusually high value for a standard 230v domestic but on a 3ph supply doesn't sound unreasonable at all.

hey dude I did my written 2391/52 yesterday and the question on the paper was single phase 230v system had a ipf 5Ka reading and then you had to code it with the regulation. And it has semi enclosed fuses but doesn’t say to what type so i found a table for S3 I think which can do 4ka I think it was so I did code this as a code 2. There wasn’t any other info and it’s the only question I’ve come away doubting myself on I’ll be honest