Using 3 phase for single phase power...?

[Jagermini]

Folks, just a quick question wondering how I can use 3 phase supply for normal single phase use. As in, say I need to put in a double socket. Do I put in two single single phase sockets and use a phase for each one? Then leave one phase unused and have them both on the same neutral? Is this how it's done?
Basically, it's for a Bain Marie for a deli, and it's running up to 12kW, so I don't want to run it on single phase. How does this setup work at all?
Any recommendations are appreciated!

 

[bernardgreen]

Folks, just a quick question wondering how I can use 3 phase supply for normal single phase use. As in, say I need to put in a double socket. Do I put in two single single phase sockets and use a phase for each one? Then leave one phase unused and have them both on the same neutral? Is this how it's done?
Basically, it's for a Bain Marie for a deli, and it's running up to 12kW, so I don't want to run it on single phase. How does this setup work at all?
Any recommendations are appreciated!

STOP NOW AND GET AN ELECTRICIAN BEFORE YOU DO SOMETHING THAT KILLS, MAIMS OR BURNS THE BUILDING DOWN

DIY work in a commercial establishment can cost the DIYer a great deal of money in fines and compensation ( even prison ) when it goes wrong

 

[riveralt]

What do the manufacturers instructions say?

Is it a single phase motor on the machine or three phase?

12kw pulls over 52Amps

 

[Jagermini]

Folks, just a quick question wondering how I can use 3 phase supply for normal single phase use. As in, say I need to put in a double socket. Do I put in two single single phase sockets and use a phase for each one? Then leave one phase unused and have them both on the same neutral? Is this how it's done?
Basically, it's for a Bain Marie for a deli, and it's running up to 12kW, so I don't want to run it on single phase. How does this setup work at all?
Any recommendations are appreciated!

STOP NOW AND GET AN ELECTRICIAN BEFORE YOU DO SOMETHING THAT KILLS, MAIMS OR BURNS THE BUILDING DOWN


DIY work in a commercial establishment can cost the DIYer a great deal of money in fines and compensation ( even prison ) when it goes wrong

Cheers for your concern, but I'm a qualified electrician, been at it for 9 years. I'm good at what I do, I've just not done this particular thing before so I need someone to tell me once, then I know it and that's that. I've worked on 3 phase a lot, I've just not had to use it for this purpose yet, I'm more used to industrial. Anyway, river, it's a single phase motor in the Bain Marie.

 

[bernardgreen]

but I'm a qualified electrician, been at it for 9 years. I'm good at what I do,.

I am not a qualified "electrician" but even I know that having two sockets in close proximity and fed by separate phases can create a very serious hazard.

 

[ericmark]

There are many considerations between single and three phase. Although one can draw a single phase supply from a three phase one if there is a neutral present this will produce an out of balance load and with the load you are talking about it is not just a case of connecting correct cables.

Many commercial units come with both single and three phase options and even a domestic hob often has a split phase option for French market.

To talk anyone through all options is not realistic and to comply with HSE requirements I strongly suggest getting an Electrician to do the work.

 

[ban-all-sheds]

Folks, just a quick question wondering how I can use 3 phase supply for normal single phase use....I don't want to run it on single phase.

¿Que?

Cheers for your concern, but I'm a qualified electrician, been at it for 9 years.

But still not au fait with single- and 3-phase...

I'm good at what I do

Then have the good sense and professional responsibility to stick at what you are good at and to not take money from people to do things you don't know about.

 

[Jagermini]

Ah sure cheers for the help anyway folks!

 

[ban-all-sheds]

Is it a single phase motor on the machine or three phase?

Why would a bain marie have a motor?

 

[holmslaw]

..

 

[Jagermini]

Grand, just one question so, do most Bain Maries come with both a single and a 3 phase option?

 

[ericmark]

I read now that you are an electrician. Well it is normal although no law or rule that sockets on different phases are far enough apart so they can't be both touched at the same time. In an office environment one would not have two phases in same room but in industrial premises this can't always be done.

In any event most cases will have the number of the MCB marked on a disc of coloured stick on to show phase used and MCB feed from.

I am assuming it is a collection of items not one? And what you want is an array of sockets that each item can be plugged into? Using a phase for each although not best idea is sometimes only option.

However if it is a single machine designed for French market with a split phase supply then I would always use a single plug. I theory we can use the three phase plug and not connect to one phase. However in the past I have been caught out and found there was no neutral to the three phase socket. So often it is safer to use a unique socket not used else where in the building to ensure it's not plugged into any socket without a neutral.

If you are going to use a 5 pin three phase socket like others in the building do check other sockets and see if the guy wiring them has connected a neutral. I had a three phase plug with three single phase in line sockets in my test lead box and I would use the ELI tester on each sockets to ensure neutral was present and well connected.

You can't draw 12Kw from a pair of 13A sockets anyway it would need a pair of 32A sockets so using a single three phase 32A socket would seem the way to go.

 

[ericmark]

Grand, just one question so, do most Bain Maries come with both a single and a 3 phase option?

The ones I have worked on could be configured in a number of ways and in some cases could be fitted with 380 volt elements (Was not in UK). One of the problems was where elements had be configured in delta or star according to voltage. And some one fitted new 220 v elements where it was in delta.

Where the elements are connected in star then loss of neutral is not so important. When 400 volt elements are connected in delta then no need for neutral.

 

[Jagermini]

Ok folks, crisis is averted. It has the options of single and 3 phase. The guy fitting it told me at first it was single phase but he wanted a 3 phase supply to it. What can I say it just confused me. Anyway, it's a straight-forward 3 phase supply, which I have no problem with installing. It was just a brain fart on my part for a short while. Cheers for the input.
It's a 9kW BM, so I work out the design current to be 13A. So I'm gonna go for a 20A MCB, sound about right?
Sorry about the questions. I think I'm pretty good at what I do, never had a complaint for shoddy work from a boss, top marks in my exams and all that, but I'm just used to being told what to do and where, this is just a job for a mate. Apologies if I'm sounding green...

 

[bernardgreen]

this is just a job for a mate. Apologies if I'm sounding green...

"Just a job" Lets hope your mate's public liability insurers will accept your work. It will be OKish if nothing goes wrong but if an insurance claim is made for harm or injury to someone and the insurance company refuse to pay then I hope you mate is a very good and generous and forgiving mate.