low Ze high pscc ????????

[tes11]

hi all testing new install warehouse units 2 of first unit Ze 0.09 PSCC 2.45 KA second unit Ze 0.01 pscc off the scale of 20 KA am i too close to sub station help lol

 

[tes11]

Help plz

HOW close is too close to a sub station ?????pscc reading off scale 20KA Ze 0.01 help ????

 

[tes11]

Re: Help plz

any help would b grateful lol

 

[Jay Sparks]

Re: Help plz

Hi Mate.

If its a tn-c-s system, ohms law, 230v over 0.09 = 2.5ka, the first unit you tested seems to be ok as long as your mcbs/fuses are rated above 2.45ka. As for the 2nd unit, the ohms law again works out right with your results but that is a high pscc! As I normally only test domestics, I'm not sure how close to a sub station you can be. Although I had a simular problem on a house, the pfc was 9ka and the rcbo's where only 6ka. I rang my boss and he said I must be close to sub station and as long as the main cut out fuse was greater than 9ka then it was ok. The cut out was a bs 1361 type 1 rated at 16.5ka. Not sure if this was ok but the boss says yeah!

Hope this helps abit, although I think I'm just pointing out the obvious.

Cheers

Jay

 

[johnboy6083]

im pretty sure that you can buy bs88 fuse with a breaking capacity of 50ka, so youshould be able to protect your installation with those.

 

[SimpleSimon]

If not 1361 type II are rated at 33Ka. Should be ok with that.

 

[IQ Electrical]

The exemption only applies with a SUPPLY fuse of type BS1361 II 100 Amps max on single phase supply where distribution boards comply with BS60439-3.

In all other scenario's normal rules for device breaking capacities apply.

 

[SimpleSimon]

The exemption only applies with a SUPPLY fuse of type BS1361 II 100 Amps max on single phase supply where distribution boards comply with BS60439-3.

In all other scenario's normal rules for device breaking capacities apply.

What would that be for BS 1362 II?

 

[IQ Electrical]

What would that be for BS 1362 II?

Do you mean a BS1361 type I ?

The annex is specific in that it only covers installations protected by a suppliers BS1361 type II fuse.

View attachment BS60439 UK Annex ZA.pdf

 

[SimpleSimon]

The exemption only applies with a SUPPLY fuse of type BS1361 II 100 Amps max on single phase supply where distribution boards comply with BS60439-3.

In all other scenario's normal rules for device breaking capacities apply.

I'm asking in other scenarios (like this one) when normal rules apply if a BS1361 type II does not have a breaking capacity of 33Ka, like you state what is it rated at?

 

[tes11]

main section board feeding db s has 50 ka rated 3 phase rcd breakers
hopefully this covers all recorded readings on submitted test sheets pointed out to office and approved
thanks all for comments

 

[pushrod]

hi all testing new install warehouse units 2 of first unit Ze 0.09 PSCC 2.45 KA second unit Ze 0.01 pscc off the scale of 20 KA am i too close to sub station help lol

Just a small point, if these are on a 3 phase board you should be recording these figures for your max PFC as either doubled (rule of thumb) or X 1.732

Still within your 50kA max mind