3Ph to Single Phase

[TPES]

Big factory, huge 3ph supply, been split into smaller individual units.

I will be taking out one of the extreamly old 3ph panels and replacing it with a split load single phase board. Isolating the other 2 phases. Running single phase only. The reason being there is only a 20a radial and 2 ligthing circuits off this huge panel.

As this is clased as industrial premises can someone tell me exactly what HAS to have RCD protection.

I plan on putting the radial circuit and toilet lighting circuits on RCD side and office lighting on main switch side. Is this ok to do??
Is there a reg that states lighting in offices has to be RCD protected?

 

[ian.settle1]

Big factory, huge 3ph supply, been split into smaller individual units.

I will be taking out one of the extreamly old 3ph panels and replacing it with a split load single phase board. Isolating the other 2 phases. Running single phase only. The reason being there is only a 20a radial and 2 ligthing circuits off this huge panel.

As this is clased as industrial premises can someone tell me exactly what HAS to have RCD protection.

I plan on putting the radial circuit and toilet lighting circuits on RCD side and office lighting on main switch side. Is this ok to do??
Is there a reg that states lighting in offices has to be RCD protected?

Check with your local DNO as if you isolate 2 phases and use only one they may not be to happy due to the loading on the one phase, also check how the factory is metered it could a KVAr meter depending upon what it was used for before.

If cables are sunk into wall and less than 50mm without earthed mechanical protetion then yes the lighting circuits have to be RCD protected.

 

[TPES]

Ok, cheers ian, Obviously if its in the regs it applies to any sector of wiring, Domestic or industrial or commercial.

There is 3 seperate meters for different areas of the building, Only one is being used as only one area of the building is being rented. The cables are cliped direct or in trunking straight from the board to the accessorie.

Ill attach a couple of photos..

If RCD Protected circuits to toilets then No supp Bonding right?

 

[montybaber]

In industrial commercial I believe RCD protection can be side-stepped on certain circuits etc due to the installation being used by skilled or instructed persons.

If a circuit is supplying socket outlets used without the supervision of skilled or instructed persons then an RCD must be used.

ps id use a three phase dis board and split your circuits over different phases to keep the load balanced as possible

 

[ian.settle1]

Why 2 meters and watch what you do around the main incomer it's one of horrible bitumin filled joint boxes.

 

[TPES]

Why 2 meters and watch what you do around the main incomer it's one of horrible bitumin filled joint boxes.

Theres actually 3 meters, and 3 isolators, Going of to 3 different panles around the building, as the building has been split into seperate rented areas by different companies.

I think ive said this on a previous thread but am i correct in saying the bonding condutor size is dependant on the size of the incoming neutral? As the incoming phases and neutral are over 50mm am i right in saying the bonding needs to be 35mm?

What about the earth to the CU, this wants to be half of the phase conductor, correct? meaning i need around 35mm again for earth?

 

[Darkwood]

When designing an installation you need to allow for future expansion and take into account the nature of the premises so in your situe i would recommend a 3ph 4 or 6way dist board the cost isnt vastly different, if customer limits this due to funding then write it on completion cert', if you do end up doing only single then reccomend telling customer to contact supplier and derate to single phase supply as they will still get standing charge for three phase, they will just remove redundant fuses, or if other premises are using 3ph supplies then they will just do a meter change.