3 Phase Help

[Delaney]

Hi all,

I need to put 3 phase sockets into my new workshop. I should have this done by electricians but I cannot currently afford to do so, as I’ve had to pay out a lot of money.
What I’m going to try and do is install the board, sockets/isolators and cable myself, which should cut a two day job (for the electricians) down to a 1 day job.

Having a look around, it’s of course more complicated than I thought it would be, so need some help identifying the right parts and any deals that anyone might know of, that can help me save more money.

I have 5 machines that need 3 phase:

1 x Bandsaw 5kw (8amps)
1 x Planer 5 kw (8amps)
1 x Wide belt sander 10 kw (28 amps)
1 x Panel Saw 4kw (8 amps)
1 x Dust Extractor 4 kw (8amps) The extractor already has cable and isolators going into a controller so is not part of this equation.

All of the machines have cable and sockets on and are ready to be plugged in to a wall socket/isolator.
I’m going to go with 32 amp wall sockets/isolators (unless suggested otherwise)
What I’m struggling to identify is the start up amperage of each machine, which will dictate the thickness of cable and breaker, unless that is already given in the overall rating?

2.5mm core cable rated at 31 amps will be fine for the 8amp machines and potentially the 28 amp wide belt sander; unless start up amperage exceeds that?
4mm core cabal running into the board from the main board (3 phase inlet into the workshop) rated at 42 amps will give me enough power to have 2 machines running, (extractor + machine).
I could though bump this up to 6mm core and get 53 amps, in case I want to run 2 machines plus extractor?

I need breakers but not sure which ones. I know for example, the wrong breaker was fitted on the wide belt sander before, and the electrician changed it to one that although rated slgithly lower than the amperage, it was a ‘c’ cat one (or something), so it could deal with the load.

Components: (This is a list so far)

1 x 8 way board 125 amp TP+N Type B (not sure what TP + N and type B means) https://www.cef.co.uk/catalogue/products/4887747

4 x 32A 4 Pin 415V Wall Mounted Interlocking Socket https://quickbit.co.uk/32a-4-pin-415v-wall-mounted-interlocking-socket/

15 x mtr 2.5mm 4 core armoured cable https://quickbit.co.uk/swa-cable-4-core-2-5mm-per-metre/

15 x mtr 6mm core armoured cable https://quickbit.co.uk/swa-cable-4-core-6mm-per-metre/

Any help would be much appreciated.

 

[ChaiLatte]

Liaise with the electrician who you will use to do the one day's work and follow their recommendations. Even if you have to pay them £100 for a shopping list of items, it is money well spent.

In order to assist them in this, find documentation on the machines or take good, clear photos of the motor data plates and send as a package to the specifying electrician, as well as a rough layout which includes the incoming supply from the electricity company (so they know approximate cable lengths - if they calculate on the basis of 25m and you need 250m, voltage drop needs to be taken into account).

If you do the stuff off your own back and the first the electrician ever sees is you presenting it as a fait accompli, any legitimate one will run away. Bring them in early, explain that you will do the grunt work in the middle and that you want to pay them for the expertise up front and at the end.

TP&N is three phase and neutral, to accomodate five pin outlets. You may not need that if none of the machines use a neutral.

See:

https://www.tlc-direct.co.uk/Technical/DataSheets/Hager/Hager_Guide.pdf

for Type A/B disambiguation.

You probably know that SWA has a minimum bend radius, so factor that in, and any support needed for a bend (e.g. horizontal run on an internal corner) when planning cable routing.

Do you have the skills to terminate the wires of the SWA cable correctly?

 

[Delaney]

Liaise with the electrician who you will use to do the one day's work and follow their recommendations. Even if you have to pay them £100 for a shopping list of items, it is money well spent.

In order to assist them in this, find documentation on the machines or take good, clear photos of the motor data plates and send as a package to the specifying electrician, as well as a rough layout which includes the incoming supply from the electricity company (so they know approximate cable lengths - if they calculate on the basis of 25m and you need 250m, voltage drop needs to be taken into account).

If you do the stuff off your own back and the first the electrician ever sees is you presenting it as a fait accompli, any legitimate one will run away. Bring them in early, explain that you will do the grunt work in the middle and that you want to pay them for the expertise up front and at the end.

TP&N is three phase and neutral, to accomodate five pin outlets. You may not need that if none of the machines use a neutral.

See:

https://www.tlc-direct.co.uk/Technical/DataSheets/Hager/Hager_Guide.pdf

for Type A/B disambiguation.

You probably know that SWA has a minimum bend radius, so factor that in, and any support needed for a bend (e.g. horizontal run on an internal corner) when planning cable routing.

Do you have the skills to terminate the wires of the SWA cable correctly?

Thanks Chai, good advice re: electrcicians. I find though that many want to do all or nothing. If they’re busy, they wont entertain something that seems otherwise. Often they respond to someone asking them to certify something, as that's straight forward work and likely more pleasant on average than doing the grunt work.

I can terminate that type of 3 phase cable. I wired up my motors on the extractor and the isolators. I’ve not wired a breaker or board yet but seems straight forward.
All of my stuff was previously installed professionally, so I copied what was done when I need to add or make any changes. Was not aware of min cable direction but thanks for letting me know.

I can pull the plug shields on the existing machines to determine the cable type.

The thing I’m most interested in is the breakers and board and wiring that.

I’ll add the motor plate details here and the plan, although not sure where the machine will go yet. Kind of important but not more important than me discovering if I can work out the breakers and wiring the board (whilst not connected). Adding the switches/isolators is the part I feel confident in doing. Getting the right board and breakers is my number one priority at the mo.

 

[Spectric]

I need to put 3 phase sockets into my new workshop.

The starting point is the type of supply to your workshop, also you need a proper electrician involved to do the design work so you use the correct components, get this wrong and you will be wasting your money on stuff that is incorrect. Also remember that 400 volts will electrocute you much easier than 230 volts so needs to be done by the right person and not a domestic installer.

I’m going to go with 32 amp wall sockets/isolators (unless suggested otherwise)
What I’m struggling to identify is the start up amperage of each machine, which will dictate the thickness of cable and breaker, unless that is already given in the overall rating?

Each socket will be on it's own protective device in the main board which will protect the cable and the 32 amp socket, what you connect has no bearing providing it is within the rating of the socket and supply. Ie you do not want a 16 amp rated device fitted with a 32 amp plug and connected to a 32 amp supply because the cable between the plug and machine will not be able to handle the fault current needed for the 32 amp circuit. You always need a protective device where there is a change in cable CSA unless you derate the protective device.

There is as you have said a lot more in this than you thought so get the design right so every passes the final testing without issues.