Old incomer connected to four 3 phase cutouts help

UKPN:

 An industrial unit from the 1960s, hence the TPN 150 amp service .It then seems in later years this became a collection of offices hence the multi cut outs. 

Are the (12) meters still installed? 

If there are to be that number of "units" and depending on the maximum power requirement, the ideal and cost effective solution may be to upgrade the existing cut outs and most likely upgrade the incomer, (which would be a minimum of 200 amp) I note the tails are insulated and sheathed, so modern.

It appears there is a satisfactory Ze. 

The space heating seems to be a general installation so likely to be part of a landlords supply.


This project depends on as always, the maximum power reqd. This will be declared to the DNO and they will take it from there. 

If the required load exceeds the available capacity, as a starter a new cable will be need to be laid. Depending on condition, they may require a Ryefield. The consumers switchgear may need to be renewed. 

Earthing and bonding will almost certainly need upgrading to (TNS) new standards. 


Pretty straight forward really. Good luck with that.

Regards, UKPN

 

Thank you, again invaluable information.

I may have more questions, forgive me.


Regards

Simon

AJJewsbury:

But could the incomer in question be a fused neutral?

I doubt they ever put a fused N on a 3-phase system - too much risk of frying loads with 415V L-N. AFAIK even in the old days N was only fused after the transition to '2-wire' circuits.


   - Andy.

AFAIK, fused neutrals were primarily used on DC systems, and sometimes retained on AC systems that had formerly been supplied with DC.

There are still existing fused neutrals on AC systems but I suspect that these were once DC.


A far less common reason would be a system that whilst AC originaly, once had BOTH poles of the supply live. For example a 220 volt circuit derived from a 3 phase 4 wire system at 127/220 volts. That would REQUIRE a fuse in each pole of the supply, and this might have been retained when the installation was later connected between one phase and the neutral of a 3 phase 4wire system  at 240/415 volts.

Simon M:

Thank you for the replies very useful.


The property is a listed 200 year old foundry converted to offices in the 60s/70s.


The intended use is education, arts spaces, maker spaces, small studios etc. So no dwellings.


Originally heated by storage heaters which have now been removed, we are at the strip out stage but plan to have panel heaters in the rooms (number to be decided).


As the storage heaters were huge old things I am presuming they would have used a lot more juice than a modern panel heater. Albeit on economy 7. 


I just have to do the calcs.


Many thanks as this puts my mind a bit more at rest regarding the power we have available.

I do have the DNO coming out in an attempt to try and get them to upgrade the incomer but I'm not holding my breath.


Regards

Simon.

Change the usage to a gym, then they will not need any heating.


Z.