3 phase to single, and back again...

[blueboar]

Hello. I'm a bit confused with the electrics on an industrial unit I'm leasing.

Ideally I'm after 3 phase - there is 3 phase coming into the building (with a 3 phase fuse box), but the previous owners wanted single phase and created a single phase set up from one of the 3 phases.

Here's a pic of what's going on:

View attachment 20307

Before I get an electrician out... how easy it would be to revert back to three phase?

(..And now thinking about it... would be possible to have 3 single phase circuits from the three phase, so keeping the original set up and adding two more single phase circuits? (Only if it were cheaper mind!)

I'm starting a little brewery on a tight budget, so any info would be much appreciated! Cheers :icon10:

 

[chrish_1977]

Best thing is get an electrician in, this is not a DIY Saturday job, a lot depends on what equipment you will be installing etc

 

[telectrix]

first, your attachment comes up as invalid. second, get a spark in there to advise. a few forum members down there that are qualified to work on 3 phase. as crish said. it's not a DIY job. single phase bites yer bum. 3 phase eats it.

 

[blueboar]

Didn't make clear but wasn't going to do myself! Just wanted a bit of background before getting someone in... always nice having a bit of knowledge. Will scout for forum members in my area. Cheers.

 

[telectrix]

good call. it's perfectly feasible to use the 3 phase DB to supply both 3 phase and single phase circuits. done properly, the loads should be taken into account and balanced, as well as possible, over the 3 phases. if you look on the " electricians in your area" forum, you'l find 1 or 2.

 

[gnuuser]

good call. it's perfectly feasible to use the 3 phase DB to supply both 3 phase and single phase circuits. done properly, the loads should be taken into account and balanced, as well as possible, over the 3 phases. if you look on the " electricians in your area" forum, you'l find 1 or 2.

i second that statement as well!
balancing the load is very important
this task is one that should be done by a commercial spark (well versed in 3 phase) or by a good industrial spark.

 

[DNS1]

i second that statement as well!
balancing the load is very important

Just out of curiosity, why is balancing the load so important?

Only ever touched 3 phase systems on sound stages when we needed to keep PA systems isolated from noisy stuff like dimmers...

 

[Tiny Spark]

Several reasons why you should balance loads.

But the main 2 being that in the case of a imbalance you get the imbalanced current flowing down the neutral.
This can cause the cable to burn up if its not up to the task and do damage further down the line to generators etc.
Also you stand the chance of overloading one of the phases.

 

[davethsparky]

Just out of curiosity, why is balancing the load so important?

Only ever touched 3 phase systems on sound stages when we needed to keep PA systems isolated from noisy stuff like dimmers...

If you're running from a generator on an outdoor stage you'll destroy the voltage regulator if its too far out of balance and the generator will start hunting (ramping engine speed up and down) and producing wildly varying voltages.

PA system isolated from dimmers? If its on the same generator or mains supply it's not going to be isolated from the dimmers.
I guess you're referring to the various hums and buzzes that dimmers get blamed for? If the audio system is grounded properly and earthing is up to scratch then there will be no problem.
It's as bad as the sound guys who demand single phase supplies because of some old wives tale about hums and electric shocks caused by using different phases.

An important thing to remember when supplying power for the sound system is that the PA won't use anywhere near the power the sound man thinks it will. A 20KW PA is unlikely to use much more than 5KW unless its really sub-heavy