Need help with clean dB on retail unit

[Damian Petsas]

Hi all , We are carrying out a refit on a retail unit and the client wants us to provide a clean dB for the till power and the data cab. Can anyone clarify best practise for configuring this in the install .
The site currently has a 3 phase incomer with 60a fuses at the distributors side.
We are intending to install a schneider acti 9 TPN 8 way board with a 125A 4pole switch isolator to feed the general lighting and power. .
The intention was to go Into Henley blocks from the meter and then split to the TPN and off to a single phase board for the clean power . Is this correct ?

Many concerns are
1. If I install like this will the phases not be unbalanced ?
2 am I better off supplying the clean dB from a MCB in the TPN board?
3 can anyone give me general advice on best practice for balancing 3 phase DBS.

i know this is a large topic .

Any advice and help would be grateful . Many thanks in Advance

 

[Pete999]

Clean power not sure what you mean by clean power.

 

[Plonker 3]

Do you mean didcated supply for the till and data, or high integrity earth on the sockets?

 

[Damian Petsas]

well a dedicated supply and mcbs to provide power to kit like the pdq machine and the data cab . So in the event that the general power is interrupted it doesn't cause issues with the tills .i.e a mcb powering the ring . It's fairly common is supermarkets

 

[Damian Petsas]

Yea DillByou got it lol

 

[Pete999]

So, are you talking a supply with a UPS backup?

 

[Pete999]

Yea DillByou got it lol

Well which one dedicated supply or clean earth?

 

[Plonker 3]

To balance the loading simply adjust it accordingly on the TP DBs if you only fit a single pahse board.

 

[Damian Petsas]

Dedicated supply .

 

[Damian Petsas]

Ok du using Henley blocks is common practice then? No need to take supply from a mcb on the TPN board . ?

 

[Plonker 3]

Well you still need a single point of isolation for the whole installation.

 

[Flanders]

I would recommend coming of your main distribution board to supply your Dedicated supply DB as Dilld says you could spred the load by the way you configure the main DB or you could fit a small 3 phase 4 way DB it depends how many circuits you need if its just a till socket and a coms cab just run 2 separate circuits from your main DB and not bother with the separate board ,Unless they want a last man out switch then that changes everything

 

[Damian Petsas]

They do want a last man out but I'm installing contractors for just the lighting for the last man out. Ok so the two options are feed db2(single phase clean dB) from mcb in TPN (db1) or to fit Henley blocks then From there feed db1 and db2 . Is that correct?

 

[Plonker 3]

Re-read post #11

 

[Flanders]

You need a main switch before the henly blocks in my opinion henly blocks look is a bit ruff so feed off You main DB As Dillb says see post 11

 

[Damian Petsas]

I've re read post 11 .dont mean to sound dumb but surely if iinstall with Helena blocks and feed both dbs . Each dB has a switch isolator therefore isolating the supply ? Or am I missing something here?

 

[Damian Petsas]

Right so feed from the meter end to a eton men TPN Isolator then off

 

[Pete999]

I've re read post 11 .dont mean to sound dumb but surely if iinstall with Helena blocks and feed both dbs . Each dB has a switch isolator therefore isolating the supply ? Or am I missing something here?

Whats Helena got to do with the job?

 

[Plonker 3]

Right so feed from the meter end to a eton men TPN Isolator then off

So you may aswell just feed it from your main DB, no point over complicating it.

 

[Damian Petsas]

Thanks for all your help guys I will be feeding from Main dB .thabks for your wise advise