Dual supplied new installation (PIR Form)

[JimmyDaWolf]

Hi

We have recently supplied a new installation for a customer of ours in an extended industrial unit. It was gutted and installed from scratch.

There is a transformer in the main sub room that feeds some really old switch-gear with a main incoming switch with 4 outgoing cubicles. We have used two of these outgoing cubicles to supply the another unit separate from this one., 1 supplies the existing half of the unit with a 90mm swa and the other supplies the new extension side of the unit with a 240mm swa. These both run into the same sub mains room and have into 2 separate main incomers. a 200A Switch and a 530A switch. although these units are bolted together via the Earth bar they are both separate. the 200A Has 2 ways, one of which feeds a DB in the old part of the unit used for storage only. The 530A feeds a board in the new half of the unit and also feed the machinery in that half.


Transformer ------Main incomer-Way 1--------530A Incomer----3 ways out to Unit 1
Way 2--------200A Incomer----2 ways out to unit 2

So out of these what would i record as the Primary supply OPD, Main Switch Or Circuit Breaker?
Main OPD for each Sub mains? Main OPD for the DB's in the units.

Im struggling on how to put all this into PIR Form. I have all the qualifications i just really struggle with these forms some times. any form for that matter.It doesn't seem like i get all this information onto the forms.

Any help would be appreciated.

 

[HandySparks]

Welcome to the forums.

I'm not familiar with industrial, but I do use PIRform. I often find myself recording, say, a switchfuse or a stand-alone RCD as a one way DB.

I agree, the standard forms don't really cover many of the situations found in practice. I frequently have circuits where the overcurrent protection is a BS 1362 fuse, but the relevant RCD is somewhere way upstream, several devices away.

 

[Engineer54]

To be honest i'm having dificulties trying to make out what your saying/describing in your OP. Pretty sure you are getting your incomer and outgoing confused along the line... lol!!

 

[JimmyDaWolf]

Maybe I haven't explained it the best. Basically there is the transformer located in the corner of unit 1 that supplies some big old switchgear. 2 of those ways are routed out of unit 1 and under a road over to unit 2. Unit 2 is then of 2 halves. A reinstated unit (unit 2a) and a new extension (unit 2b) both these supplies come into the same sub mains and onto some new switchgear that is bolted together by the earth only. A 240mm cable supplies a 500A switch that then branches off into unit 2b. A 90mm cable supplies the other half Unit 2a. At the moment the only way I can see of doing it is two separate installation certificates. One for each supply. Reason being I only have one page available to input the supply characteristics and earthing. Hope this makes more sense.

 

[Sintra]

From what I can make of this you have 2 sub mains coming from a single source. That single source is your supply ie the big old switchgear that you refer to.

 

[JimmyDaWolf]

The transformer feeds a big 600A switch that has 6 outgoing cubicles. 2 of which feed units 2a and 2b seperately.

 

[Engineer54]

If only you could post some photo's, all would then become clear!! ...lol!!

But to save time and confusion, conduct and issue 2 EIRC's (or whatever they are called now). The Primary supplies are the 2 cubicles feeding the units 2a and 2b, Take the Ze value for both outgoing supply cubicles (if possible) at the incoming of the main 600A S/Fuse... ...I hope you're MFT or Loop tester has a good enough resolution, capable of reading very low Ze values!!! lol!!

Any further boards you test downstream, can/should be classified as Zdb, basically a board Zs test and value...