3 Phase PSCC testing.

**Derlyn** · 24-Feb-25, 07:41 PM

Hi All

Not often I work on 3 phase installations but I'm busy testing a 12 DB, 3 phase installation presently.

Is this a silly question ?

I've carried out the PSCC test on the main board from each phase.
The results are all within spec, however, the results from each phase are not the same. They differ.
The test report asks for and has place for only one reading.
Which one is entered on the test report ?

**AndyD** · 25-Feb-25, 06:39 PM

Just use the highest reading out of the three.

**Derlyn** · 25-Feb-25, 08:00 PM

Originally Posted by AndyD

Just use the highest reading out of the three.

Thank you, brother. I thought that would be the way to go. Always lekker to get confirmation.

**Derlyn** · 25-Feb-25, 08:07 PM

Another quick question, brothers.

There's a 25Kva generator feeding the whole main DB through a change over switch.

All the sub DB's are fed directly from the main DB.

My question is ........ Do the sub DB's have an alternate power supply connection or is it only the main DB ?

**GCE** · 28-Feb-25, 10:46 AM

Originally Posted by Derlyn

Another quick question, brothers.

There's a 25Kva generator feeding the whole main DB through a change over switch.

All the sub DB's are fed directly from the main DB.

My question is ........ Do the sub DB's have an alternate power supply connection or is it only the main DB ?

Been pondering on the question
Not sure on the correct answer but was tossing around with the point of control being the decision as to whether it does need or not.

My tendency is to say the sub DB's do not need a 2nd test report just main DB which goes along with do I need indication at those sub DB's for generator power or utility power and I use point of control/isolation as the measure.

If I turn the sub DB isolator off and the complete board is off even if gen is running then , No 2nd report .
I back that decision up with a shopping Centre scenario - There are 100 shops , the complete Centre is run from generator or utility and I am doing the little pie shop of 10sqm - Do I need to request Centre management to do a mains fail so I can take 2 different readings ?
It would not be practical and at the end of the day I only have one supply cable from the "supplier" ( supplier by definition being Centre Management)