3P and 1P in Commercial Premises

[sleepyfolk]

hi folks, just after some opinions as we’ve had some differing advice so far.

We’ve just bought a small ind unit which has an ancient 3P and 1P panel with rewireable fuses.

We need to upgrade as we want 3 ringmains, one for the office, one for the rear workshop area and one for the front workshop area. We have 2 wash machines and tumble dryers that we’re going to be split across the 2 workshop rings. Ground floor area is 74sqm.
You can see the boxes in the right hand corner of the photo, it is a bit cleaner and whiter now in there!

We only have one item that requires 3 phase, a 2 post Bradbury garage ramp that will be used occasionally.

One person I had in says he’d just change the single phase consumer unit, the other says put a new 3P board in and use the spare ways to supply the single phase circuits spreading the load across the phases.

Not quite sure which is the best/safest way to proceed, don’t really want to spend money then find out it should have been done a different way!

I do have some understanding/experience of electrical systems from ships but not so much from land based systems so hopefully your answers will make sense.

 

[mhar]

To balance the load you would need to use the 3 phase distribution board. Using the single phase board would put all the loads (exc the occasional light ramp load ) on one phase.
How often are the wash machines and dryer going to be running? 13A plug machines?

 

[Deleted member 26818]

Use the 3 phase board and try to balance the loads.

 

[The Ghost]

What exists currently, is there any need to do the work you propose and why? Have you got an EICR for the installation, have you thought of getting one prior to starting what may be unnecessary work? The differing opinions are just a reflection of the many solutions that may be possible for the work in question. In summary use the three phase supply. Is the single phase a sub main from the three phase?

 

[LankyWill]

Get rid of the single phase board and fit one TP+N board, just balance the loads and you will be future proof for further 3 phase loads. I like Memesheild 3 or Hager TP+N boards as there widely available with breakers to suit. There’s probably asbestos in your current switch fused disconnecter so I’d get a new one fitted when you change your dis board change.

 

[sleepyfolk]

There is a 3 phase supply via a 63a isolator, the single phase board is tapped off the blue phase (in old money!) , the chap that said he could just change the board for us I think was more used to houses hence coming on here to ask. He is a friend of a friend type thing,.
The 2 washing machines and tumble dryers are normal domestic types with 13a plugs and run pretty much all day. There is also a 3kw water heater. There are no other large items just computers, screens, printers etc.
We have decided to upgrade it as there aren’t enough circuits on the old 1P board and I also thought it would be a bad idea to have everything in the unit hanging off one phase.

From my limited experience it seemed logical to use a 3P board and split the other circuits across the phases which is what the proper spark said but just thought I’d check with some unbiased opinions that weren’t charging me money.

 

[Pete999]

There is a 3 phase supply via a 63a isolator, the single phase board is tapped off the blue phase (in old money!) , the chap that said he could just change the board for us I think was more used to houses hence coming on here to ask. He is a friend of a friend type thing,.
The 2 washing machines and tumble dryers are normal domestic types with 13a plugs and run pretty much all day. There is also a 3kw water heater. There are no other large items just computers, screens, printers etc.
We have decided to upgrade it as there aren’t enough circuits on the old 1P board and I also thought it would be a bad idea to have everything in the unit hanging off one phase.

From my limited experience it seemed logical to use a 3P board and split the other circuits across the phases which is what the proper spark said but just thought I’d check with some unbiased opinions that weren’t charging me money.

What exactly do you mean by "proper spark"? you will need to employ an Electrician with a suitable skill set, in 3 phase circuitry, definitely not something you should try and do by yourself.

 

[sleepyfolk]

I’m not sure the friend of my brother in laws is suitably qualified, that’s why I’m asking if his proposal to just change out the single phase board is ok, seems that everyone’s advice is to change the 3P and run everything off that so we’ll go down that road, thanks for everyone’s help

 

[GMES]

As already suggested by others, I would go for a 3 phase DB and balance all the circuits in that, My personal preference would be Merlin/Schneider.

 

[Pete999]

As already suggested by others, I would go for a 3 phase DB and balance all the circuits in that, My personal preference would be Merlin/Schneider.

Blimey I thought you were talking about the "Spitfire" probably only people of a certain age will understand. Or maybe WW2 aircraft enthusiast.

 

[plugsandsparks]

|No brainer, loose the Sp board, put in a new TP board and run all ccts from it. Much safer as you can loose the fusewire and have proper breakers and even an RCD or two and of course you can manage the balance better, if needed.

 

[Toneyz]

New 3 phase board enough spare ways for future.

 

[sleepyfolk]

Many thanks folks