3 Phase supply

[sparkyste1]

Hi all,
Have been asked to price up job and a little unsure on the following.

Currently the property is 1 big unit with a 100amp per phase, 3 phase supply coming in.
The owner wants to split the unit in to 3 different units, but without having new supplies added.
Can I, install the current 3 phase supply in to a distribution board, come out of a 63amp 3 phase MCB and feed each unit this way?
Units are currently empty, so not sure what load will be use in each individual unit.
If so or if not, any additional help or advice would be really appreciated.

Any questions please ask.

 

[spark 68]

More information is required, do you need a single phase supply in each unit or do you need three phase in each unit for a start.

 

[sparkyste1]

Sorry
3 phase supply in each unit.

 

[R G]

For what you are planning you would need to find out the Maximum loading into each of these 3 units and what sort of supply they need ..

 

[spud1]

You will need to consider the likely maximum demands of the units and their likely use to determine suitable sized supplies. Also consideration for sub metering sounds like it may be needed?

 

[Sintra]

What about metering?

 

[davesparks]

You'll want to consider discrimination too

 

[Bobster]

Maybe hire someone with more experience to help, so you can learn hands on what is needed?

 

[ImpededLoop]

Sounds fine. The main intake may need to be enclosed in a landlords area to prevent the tenants tinkering. You may also want to install a check meter for each unit so the landlord can split the electricity bills appropriately.

If bonding is required in each unit, you'll need to consider the size of your earthing conductors in your submains or run separate bonding back to the MET.

 

[spud1]

What about metering?

Just sounds like the 3No. 'units' might be rentals. Different tenants = metering probably required

 

[Charlie_]

The existing supply that you mention, is this a metered supply from the DNO?..
if so then the best way forward would to get them involved, change the head to a multi way service head with local separate metering, supplying a TPN isolator and then onto each unit

 

[7029 dave]

3phase on each unit, I would suggest supply meter on each unit= new supplies on each unit.

 

[sparkyste1]

Got the experience to carry out the installation but wasn't sure about whether a 63amp supply would be deemed as sufficient or even allowed. Sorry rob but the whole idea of a forum is so when we get stuck on something we have help to turn to.
As to every one else, yes I understand we would need t know what load is expected to be pulled. Again sorry but yes we have mentioned about each unit having there own meter.

 

[davesparks]

How the hell are we going to know if 63A is sufficient when you are the only person here who knows the maximum demand you have calculated for each unit?

 

[ImpededLoop]

... wasn't sure about whether a 63amp supply would be deemed as sufficient or even allowed.

It's impossible to say without knowing what the units are to be used for.

 

[Bobster]

You may have the experience to install it, to design it questionable.

Your not going to get anyone willing to hold your hand on a forum, just point you in the right direction.

So my advice still stands, get someone hands on that will help.

 

[7029 dave]

IMO 100amp cut out (3phase) is no where big enough for 3 units, 400amp maybe 200amp at an push (multi way route), on that note better to have new supplies installed to each unit, may work out cheaper.

 

[sparkyste1]

going to inspect the job for first time tomorrow, info I have passed to you is all from 2nd hand info I have been given so far.
Know what questions I need to ask now and potentially what answers I need to give so thanks to all for your advice.
Again Rob, I do not want someone to hold my hand, do the work for me or anything else you might want to comment. I was asking for advise. All you seem to want to do is criticise and put people down. So please stop posting, alternatively you maybe better suited for a job with Jeremy Kyle.

 

[spark 68]

Again Rob, I do not want someone to hold my hand, do the work for me or anything else you might want to comment. I was asking for advise. All you seem to want to do is criticise and put people down. So please stop posting, alternatively you maybe better suited for a job with Jeremy Kyle.

A bit harsh there, I think you will find Rob is one of the more helpful posters on here, his advice is sound as by asking the original question it sounds as though you are unsure yourself.

 

[sparkyste1]

A bit harsh there, I think you will find Rob is one of the more helpful posters on here, his advice is sound as by asking the original question it sounds as though you are unsure yourself.

You may be right but I only asked the question as we all have to start somewhere, I've got installs down to a tee. If going to price a job it would be great to know questions to ask, things to look for etc. of all robs replies, it just seemed like he was implying I shouldn't be quoting this at all. Reverting back to what I've just said, if I don't learn how will I know for future reference.

 

[Anthony S]

You may be right but I only asked the question as we all have to start somewhere, I've got installs down to a tee. If going to price a job it would be great to know questions to ask, things to look for etc. of all robs replies, it just seemed like he was implying I shouldn't be quoting this at all. Reverting back to what I've just said, if I don't learn how will I know for future reference.

Nothing to do with the quoting, anyone can put a price on a job, its the designing of it that needs some thought.

Your mean't to be Qualified and designing is part of your training when doing your Qualifications.

ie use of buildings, demand, wiring systems and so forth. Your asking basic questions imo

 

[spark 68]

Well one way to learn is by shadowing someone who already knows how to do something.

To be fair if you are not really sure how to design this properly for it's intended purpose then you could end up right in the s*it, this is why Rob was suggesting you seeking some hands on help.
As he said, installing it will likely be easy enough for you, designing it is something else completely different.

You are right we all have to start somewhere, usually we learned by assisting others who already knew what they were doing,and by learning why things are done certain ways, asking daft questions and the like , nobody suggested you are a substandard spark in any way shape or form, sometimes it is better to know enough to know that we don't know enough if you catch my drift, there is no disgrace from asking someone to help you out, particularly if you are unsure.

Learning on the job and making mistakes with a 3 phase supply and distribution is not really the best way of learning though, it could seriously backfire and as I say land you in the s*it.

 

[sparkyste1]

Nothing to do with the quoting, anyone can put a price on a job, its the designing of it that needs some thought.

Your mean't to be Qualified and designing is part of your training when doing your Qualifications.

ie use of buildings, demand, wiring systems and so forth. Your asking basic questions imo

Mot maybe basic but after a long day we can all have blank moments.
I was given info before seeing the job.
i want to install a distribution board, and feed each until from a 3phase Mcb. Each unit will have its own 3phase supply. Ok I forgot to mention the individual meter for each unit.
is this allowed? That was my main question. I then left for people to comment on any other advise I might find helpful. So forgive me if I'm moaning at other people who seem to be putting me down.

 

[Anthony S]

Mot maybe basic but after a long day we can all have blank moments.
I was given info before seeing the job.
i want to install a distribution board, and feed each until from a 3phase Mcb. Each unit will have its own 3phase supply. Ok I forgot to mention the individual meter for each unit.
is this allowed? That was my main question. I then left for people to comment on any other advise I might find helpful. So forgive me if I'm moaning at other people who seem to be putting me down.

Go and look at the job make notes and ask what the units are going to be used for etc

Then clear your head and draw up a plan and go from there, don't let customers badger you into committing on something you need to put some thought into because they want a price within hours.

 

[ipf]

You may be right but I only asked the question as we all have to start somewhere, I've got installs down to a tee. If going to price a job it would be great to know questions to ask, things to look for etc. of all robs replies, it just seemed like he was implying I shouldn't be quoting this at all. Reverting back to what I've just said, if I don't learn how will I know for future reference.

I think the indication is that you may get stung. Going in above your head can bite back badly. Anyone can quote for a job....it's understanding what they're quoting for. No spec for the job so, basically, you're doing it. A bit more thought before the criticism would be a help.

 

[netblindpaul]

IMO 100amp cut out (3phase) is no where big enough for 3 units, 400amp maybe 200amp at an push (multi way route), on that note better to have new supplies installed to each unit, may work out cheaper.

I have a small unit in an old factory which is split into 30 units.
The incoming DNO fuses for the whole building are 200A.
I have seen inside the head, after one blew following a fire in one of the units melting a sub main.

Dai Varsity is a wonderful player!

 

[davesparks]

IMO 100amp cut out (3phase) is no where big enough for 3 units, 400amp maybe 200amp at an push (multi way route), on that note better to have new supplies installed to each unit, may work out cheaper.

How can you possibly say that without knowing the maximum demand etc of each unit? they could easily be 3 storage warehouses which only need lighting and a roller door

 

[7029 dave]

How can you possibly say that without knowing the maximum demand etc of each unit? they could easily be 3 storage warehouses which only need lighting and a roller door

Well he did say that he needed an 3phase supply for each unit, that speaks for its self.

 

[telectrix]

3 phase roller shutter door?

 

[ipf]

Well he did say that he needed an 3phase supply for each unit, that speaks for its self.

Yeah, can't say I've come across any decent size units with single phase supplies. Have to be a bit of a teeny weeny one IMO.

 

[davesparks]

Well he did say that he needed an 3phase supply for each unit, that speaks for its self.

3phase does not necessarily equal high current demand. It could just be the roller door that needs it.

 

[atm84]

Not read all the posts but apply to the DNO for a Ryefield cut out and then each tenant can apply for their own meter. If I was renting a unit, then I wouldn't want the landlord or other tent ants dictating who I buy my electricity from.

 

[atm84]

Is the landlord renting these out under a formal contract?

 

[7029 dave]

Not read all the posts but apply to the DNO for a Ryefield cut out and then each tenant can apply for their own meter. If I was renting a unit, then I wouldn't want the landlord or other tent ants dictating who I buy my electricity from.

The op has only got an 100amp 3phase supply, the dno will not fit an multi way on that, unless the supply cable is big enough for upgrade.

 

[davesparks]

Not read all the posts but apply to the DNO for a Ryefield cut out and then each tenant can apply for their own meter. If I was renting a unit, then I wouldn't want the landlord or other tent ants dictating who I buy my electricity from.

You'll be screwed on a lot of small industrial estates then! Lots of them have a single supply and sub-metering in each unit.