A DIYer's question about Industrial wiring

[Deleted member 102649]

First, apologies for the lengthy explanation that follows. What's more, I'm not sure that my questions fit into here, or the DIY bracket. Bump if necessary.
More important, I'm NOT doing the work myself, a professional will be. However, I'm after a bit of advice, so I'll try and set the scene.

I have a house that's supplied with 3 phase. The central heating is 3 phase, the rest of the installation, recently upgraded by the same company that will do the work, is fed and balanced over the phases.
I have an agreement with them that I provide all the materials and they do the work on a as-and-when and a fill-the-gaps basis, when things are quiet for them. It works very well for both of us.
Right, here goes.
In my Utility Room is a very nice, new Schneider Acti9 36 way 3 phase DB.
Everything goes through it, all except the heating fed from individual RCBOs and the incomers are just below it along with the Economy 7 switchgear.
In my garage/workshop, through the wall behind it, is a recently acquired lathe, soon to be followed by a milling machine.
The lathe has a 5 HP, 3 phase motor, the mill will probably be similar.
The lathe has a DOL starter (it says) and was fed with 3 phase wires plus an earth - before the seller chopped them off! No neutral shown in the instruction book diagram, nor evident on the machine's connection isolator. The motor is run up and stays running, spindle brought into life by a clutch.
Questions:
1. Taking into account the Mill might well require 3 phase and neutral, (the one I'm negotiating for has a 3 phase main motor and single phase feed/coolant motors) what is the best means of running the power from my DB to the garage (about 11 metres max)?
2. Would I put RCBO protection in a DB in the garage, or on the main board?
I can supply photos of the existing DB, if needed.
If you wonder why I don't just leave them to it, like I said, I supply, they (electricians) arrive, do job, go. If I get them to come and look/specify, that means more visits, more cost. I'm a pensioner!
That said, they will surely tell me if I've got it wrong. I know the boss. I went to school with him - and I don't know why he's still working, other than he just can't quit, bless him.
Will

 

[MDJ]

I am amazed to be honest you are asking us here, you have sparks lined up (apparently) and your asking us questions they can answer for you as your supplying the materials, I think-------------and I may be wrong, you are doing the work and your here for free advice, heres mine= get a spark in.

 

[Strima]

Again I would be asking your spark to design the installation as they’ll be installing and testing it.

 

[Wilko]

The designer will specify what's needed - I wouldn't try to guess what's needed from afar. Many Electricians will do a free quote.

 

[davesparks]

For a workshop I’d say steel conduit is the most sensible wiring system.

 

[paleosparky13]

You need to advise the Distribution Network about motors you're gonna be using in your installation... (2 x > 3.5kw) motors could cause imbalances across phases especially on start up. A good spark will be able to handle the correspondance between you (laymen) and them.

 

[ipf]

You need to advise the Distribution Network about motors you're gonna be using in your installation... (2 x > 3.5kw) motors could cause imbalances across phases especially on start up. A good spark will be able to handle the correspondance between you (laymen) and them.

You've got me there. Explanation please.

 

[MDJ]

You've got me there. Explanation please.

and everyone else looking at this thread.

 

[Deleted member 26818]

I would run two armoured cables 3 core for the lathe and 4/5 core for the mill, to two rotary isolators.
From the rotary isolators, I would run some 4 core HO7 cable to the lathe and some 5 core HO7 cable to the mill.
Sizing of the cable and the breakers would depend on the load each machine would be expected to draw.

 

[paleosparky13]

Apologies conflating a problem I had with phases being unbalanced at generator/transformer.. probably not a phase issue although if the domestic premesis is on a 3 phase wye distribution system it could create imbalances in that network probably not related to this issue. Being a domestic/mixed use premises using motors on start up increase demand on network loads. By many orders. They will need to know and make sure they can cope. (Sorry for the confusion. I went to the gym for the first time a million years today and I'm only single phase this evening.)

 

[Deleted member 102649]

I had expected to get a negative response along the way, maybe more than one - but I didn't expect it to be the very first one I received. Neither did I expect it to pretty much accuse me of lying, or assume I was doing the job myself.
I will be getting the professionals in but having lost well over £1,000 rectifying the mess left by a previous professional, I'm trying to recoup some of it and save money sourcing materials and prepping the job. If I wait until my Sparks has a free afternoon, always short notice, I'm up against it and end up having to go to the likes of City Electrical and pay through the nose for materials.
What's the use of a forum if you daren't ask a question?
A bit sad really but in the months and months I've read posts on here, it does seem to be a common theme in the responses quite a lot of folk get to questions on this site. It's from a small percentage of the people who use it but I have NEVER seen a forum as bad as this.
From a layman's point of view it seems a surprisingly high percentage of Sparks have a deep seated negativity, or a desperate need to down their fellow man, especially if they're not a professional - and I know I'm not the only one disappointed by the attitude of a minority.
In addition, I'm not bl**dy stupid enough to poke my fingers in a 415 volt board to DIY it, so please don't assume I am and treat me like an idiot. Not all non-professionals are incompetents - in any walk of life. Some of us actually have actively acquired enough knowledge and have enough sense to be able to avoid danger or injury quite effectively.

That apart, my thanks to those who have made the effort to give a bit of positive information. It's appreciated. I begin to get an idea of what's likely to be involved, ie, more Sparks time, more money. Hey, ho. I will get my lathe up and running one day.
Will

 

[Pete999]

and everyone else looking at this thread.

And Me

 

[Octopus]

If I wait until my Sparks has a free afternoon, always short notice, I'm up against it and end up having to go to the likes of City Electrical and pay through the nose for materials.

Hum .............. this is probably where your own approach is costing you. Why are you faffing around on the day going to get parts ? That doesn't make sense either.

This maybe not what you want to hear!

Get quotes, pick the one that suits you best, probably allow the spark to get all the kit - then agree a date and then it will be done.

You are asking for trouble "waiting" until the last minute, as and when a spark is free ....

 

[Pete999]

Hum .............. this is probably where your own approach is costing you. Why are you faffing around on the day going to get parts ? That doesn't make sense either.

This maybe not what you want to hear!

Get quotes, pick the one that suits you best, probably allow the spark to get all the kit - then agree a date and then it will be done.

You are asking for trouble "waiting" until the last minute, as and when a spark is free ....

I agree with the above, I hope I'm wrong but it sounds as though the work is being done by your goodself, and waiting intimates to me that the waiting, occurs when you find yourself in trouble and need to find out what to do next.
Providing the materials and equipment yourself, is if I am being honest is a false economy, you sound by your post that you have some theoretical knowledge, Do yourself a favour get a spark in to cast and do the work, leave it to the pros.

 

[Deleted member 102649]

Hum .............. this is probably where your own approach is costing you. Why are you faffing around on the day going to get parts ? That doesn't make sense either.

This maybe not what you want to hear!

Get quotes, pick the one that suits you best, probably allow the spark to get all the kit - then agree a date and then it will be done.

You are asking for trouble "waiting" until the last minute, as and when a spark is free ....

I quite take your point, Murdoch and yes, there's always that danger.
My reasoning for the approach I've used is that I now have a Sparks I can trust and if I do it right he doesn't have to run around sourcing bits and I get a good job done at a good price.
Like I said, I'm retired, I have the time and if an electrics job gets done this week, or next month, generally it doesn't matter. I have plenty to do renovating and building the rest of the house.
Without any shadow of doubt, I've found that shopping around - and having the time to do it - saves a LOT on materials. The Sparks can't afford to spend half an hour on the internet looking for the best deal but I can. He has to go to either the nearest supplier, or his regular supplier and accept what they offer. An instance of this was the sourcing of the RCBOs for the DB. I got most of them, all new, ranging in price from £18 to £24. The ones I didn't have, or that weren't in stock from my usual supplier, had to come from a local supplier (the exact same one the Sparks uses) at £45+ each. He ordered them, I collected them - and it was painful. From experience I've found that once a supplier has your sole attention, the prices tend to drift upwards. It certainly applies to Builder's Merchants as well.

Pete999: Your hopes are fulfilled and I'm afraid you are mistaken - and I'm not in trouble. Yes, I'm pretty confident I could do it safely and properly and I have in the past. I built dozens of phase converters for individual motors and connected up lots of machines but things have changed, especially the rules and the consequences of it going wrong.
I'm most certainly not doing the work this time, unless you call aiming to make a few holes in walls, screwing on a box, or two or running a length of conduit 'doing the work your good self'. Maybe it was the way I wrote it but the whole point is I'm not waiting to the last minute to source bits. I'm trying to get ahead of the drag curve.
Unfortunately I seem to be a lone voice trying a slightly different approach. I'm spending more time reading and answering reasons why I should not take the approach, rather than reading about what I should be looking for.
Will