Zs on 2391

[jonnyspeed]

Hi, when doing periodic on 2391 do I calculate zs for motor circuit and MIMS radial?( if not then how? )

With the ring circuit I can test zs with socket tester and lights on db from ceiling rose? Is this correct as there are a just a few things I'm not sure of?

jonny

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[Brian 157]

You'll be expected to measure Zs at the sockets but calculating is acceptable for other circuits. It's probably safer to calculate the motor circuit where you should have three R1+R2 values. Add Ze to the values & record the highest as Zs for the motor circuit.

 

[jonnyspeed]

One more thing. When re-energising after continuity and IR tests are completed on 3phase board and db,.. to find the PFC of the db will I need to safely isolate it first/before with lock+key or will the cover be already left off with main switch off and PFC performed along with zdb(ze) test? Sorry about this, this is my last question on this I promise ;0)

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[Brian 157]

The point of isolation is usually seperate to the TP DB, if not leave the DB main switch locked off & test on the incoming side of the main switch where the incoming tails will be live.

 

[jonnyspeed]

Thankyou. I think I just needed confirmation that I would be working safely as it's a fail if not. Especially on safe isloation!

So when I re-energise the TP DB I will leave the cover off the other Db and lock off. Then test ze, PFC. Replace the cover then re-energise to do zs tests, rcd test and functional?

Just a thought.. I Should test phase rotation with TP DB cover off before re-energising right?

Actually, can I just replace the covers after re-energising?

I think I've confused myself ;0(

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[jonnyspeed]

I know I promised but I'd rather understand it all before I get there. ;0)

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