pfc question

[j.capes]

Hi all,

Do you need to test PFC at a sub board if the PFC reading for the main board which is supplying it is ok?

 

[JPA]

Hi j.capes

will the PFC at a sub board be higher or lower than that at an upstream board?

clue, bear in mind the resistance of the submain

Jon

 

[apprentice87]

Hi All,

I would say yes, as the sub board might even have its own separate earthing system, [or, more likely, parallel paths] which might well give a higher figure for PEFC even though, due to the longer conductor length, you might well expect it to be lower. For example, the first board might be bolted to a brick pillar, but the second board, only a few feet away on the other side of a wall perhaps, might be bolted to, and bonded to, a steel framed shed.

john...

 

[JPA]

Good point apprentice87,

was going to add (after op had answered) that it would be a good idea to check PFC while doing the submain Zs or boards Zdb

Jon

 

[Ash]

new schedule of tests requires Ipf of DB

 

[Technician]

I understood that there was a reg that required the

establishing of a fault current value at every point

in an installation.

 

[Andy™]

Hi All,I would say yes, as the sub board might even have its own separate earthing system, [or, more likely, parallel paths] which might well give a higher figure for PEFC even though, due to the longer conductor length, you might well expect it to be lower. For example, the first board might be bolted to a brick pillar, but the second board, only a few feet away on the other side of a wall perhaps, might be bolted to, and bonded to, a steel framed shed.

john...

i very much doubt the 2nd or any other boards would have a higher PFC than the 1st