Hi PFC!

[dazza69]

Hi guys just wondered what your thoughts are on this. Been out to a city center post office today it used to be a bank but has been recently converted. One of the contractors involved was fitting new chiller units for the shop side but refused to connect into the board because the PFC was higher than the rated MCB's. On investigation there is a local transformer on the other side of the wall to the incoming supply and board and after testing have got the same results as the chiller guy. Ze of 0.01 ohms and a PFC on any single phase (L1,L2&L3) of >24KA that then being doubled to >48KA. The MCB's that are installed now are 6KA! My question is, is the only route now to install a new panel board with 50KA MCCB's in it? and do i have to feed a seperate CU off this to supply the socket circuits and add earth leakage protection that way as i don't think i can get MCCB's that do both. Any thoughts would be appreciated.

 

[Spudnik]

Recent debate here:

http://www.electriciansforums.net/e...ies-electrical-regulations/5142-high-pfc.html

Also have a read of Reg 434.5.1.

 

[dazza69]

Does that mean that if the main switch is rated to 50KA then the MCB's can be rated lower?

 

[Spudnik]

Yes but a main switch is not a protective device.

BS88 would do the trick.

 

[dazza69]

If the three phase supplies each have there own BS88 from the distributer wouldn't that already cover it?