Connecting a 50A Single Phase System to 3 Phase

**Sean_66** · 12-Oct-23, 06:17 PM

Hi guys

I have a small craft brewery that has just started up. My brewing system is a 50A single phase system, running two 5500w elements at a time. Control panel is wired for single phase.

The brewery is based in a small village shopping centre running on 3 phase and the shopping centre electrician made quite a significant stuff up. I requested an 80A single phase power supply to my brewery so the guy set up my DB board accordingly with the correct breakers etc. except the main power supply cable coming in is rated at 40A, essentially two 4mm wires for the live and neutral. which is connected to a 40A 3 phase DB board further down the line. I have no idea how he did not realise this but he went ahead anyway and apparently did not realise it himself. The cable looked suspiciously thin to me but I trusted him and after a number of successful tests with no issue, the 40A 3 phase breaker began to trip. I'm pretty certain the electrician isn't qualified.

My question is the following... If I can bring a 40A 3 phase power supply into the brewery and make my DB board 3 phase. Would I be able to hook up my single phase 50A control panel for the brewing system to it and be okay? As far as I am aware 3 phase uses less current in relation to wattage versus single phase but as the brewing system panel and wiring to elements is single phase I don't know if it'll make a difference and will still use the 50A, ultimately tripping the 40A 3 phase breaker anyway.

Also keep in mind that this DB also has to run lights, plugs and two compressors pulling 900w each. No geyser. The brewing system doesn't run all day every day of course but there will likely be points when everything may run at the same time.

Appreciate any advice given on the matter

**Dylboy** · 12-Oct-23, 06:35 PM

Yeah sherbet bud, you need to upgrade the supply cable to get 80Amps, even though it's 3 phase you are correct in that your machine / boiler is single so there is no current splitting and all that.

Not sure how far you are to the main DB supply. There may be some issues of them tripping the main breaker if you are shared with other rentals.

There are wiser guys on here who I. Hoping will chime in. There is a lot about 3 phase balancing etc..but for large premises of what I picture I don't have experience as never been exposed to it unfortunately.

Second thing is where you based ? Keen to try a local brewed beer haha

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**Sean_66** · 12-Oct-23, 07:01 PM

Originally Posted by Dylboy

Yeah sherbet bud, you need to upgrade the supply cable to get 80Amps, even though it's 3 phase you are correct in that your machine / boiler is single so there is no current splitting and all that.

Not sure how far you are to the main DB supply. There may be some issues of them tripping the main breaker if you are shared with other rentals.

There are wiser guys on here who I. Hoping will chime in. There is a lot about 3 phase balancing etc..but for large premises of what I picture I don't have experience as never been exposed to it unfortunately.

Second thing is where you based ? Keen to try a local brewed beer haha

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Thanks for your reply. Yip I'm fuming here. I've been in the premises for a year now. Licensing took 9 months to get. Before taking the place, I asked the centre owner if I'll be able to get 80A single phase in there and he made it seem like no issue at all. Did a number of test brews over a few months with no issue but murphy's law the 3 phase 40A breaker further down the line is tripping now when I run the brewing system at full tilt. Fortunately no fires!!!

There is quite a network of DB boards jotted around the center. After talking with the "electrician" today he says there are no capable DB boards nearby so it looks like we may be running a really long 16mm cable from somewhere and that won't be cheap. He said he needs to investigate and will let me know tomorrow.

The brewery is based in White River, Mpumalanga. Definitely pop in if you're in the area. Genesis Brewing Company

**Dylboy** · 12-Oct-23, 07:27 PM

Ah I am so sorry to hear !!

I hope it's not far the big main distribution board otherwise may need an even bigger cable for volt drop.

Is your machine with the 2x 5500 watt elements able to be supplied through 2 different phases? Reason I ask is then for load management of the centre you can run one element on phase and the other on blue phase, that way it should not then trip the main DB with one overloaded phase.

So basically bring in 3 phase and perhaps use 1 phase for boiler element 1 and the second for element 2 and the 3rd for the rest, that way a bit better balanced and less chance of tripping due to overload on one phase with the rest of the buildings.

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**Dylboy** · 12-Oct-23, 07:28 PM

And that is great ! We may be heading that route to Kruger in a month's times, not sure which route we taking yet but if we in the areas will pop through if we can

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**Isetech** · 13-Oct-23, 04:28 AM

What about converting the system to a multi phase system (5500 watts is only 24 amp and 900 watt is on 4 amps) 40amps x 3 = 120 amp. balancing across the phases.

I would be looking at the cost involved in upgrading the power to 60 per phase (16 mm x 4 cable) to 80 amps single phase (25 mm x 2 core) and all the components.

Compared to splitting the load on the equipment, you need an electrician ( one who has a real qualification, experience and the skill to understand basic electricity, I wish you luck with that) and a new control box, it might be easier to just upgrade.