15 AMP some new outlet

Old 10-06-17, 04:41 AM
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15 AMP some new outlet

Hi , we have a workshop with both three phase and single phase power source
wiring is really old , we are installing some new machinery which is recommended for 15 AMP power source ,
My question is should i wire a single cable and single circuit breaker for each machinery ??
or wire a three phase cable with 68 amp three phase circuit breaker from main panel and get 3 amps outlet single phase of each phase for each machinery ?
distance is around 20 meter from panel

Thanks for help in advance
Old 10-06-17, 10:26 AM
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Welcome to the forums from down under.

Each single phase machine should have its own line and single 15A breaker.

If you ran a three phase cable and then just branched off of each phase to a receptacle..... the receptacles would be protected at 68A each which would not be allowable.
Old 10-06-17, 01:46 PM
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There is more to 3-phase than mentioned. You need to be sure you have 120 volts and not 208 volts between the the hot you run and neutral. Your question shows lack of experience. I'd suggest you hire an electrician.
Old 10-06-17, 01:54 PM
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Good points Ray.

Power in Australia is 50Hz - Single phase 240v and 3-phase 415v.
I don't believe there is 120v in use in Australia..... just 240v to ground.

But.... three phase voltages can be much higher than 240v per leg so caution in connecting any equipment needs to be used.
Old 10-07-17, 07:47 PM
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The published or official voltage of a 3 phase circuit is the highest voltage between any two conductors (not counting an equipment grounding condudtor), which would be the voltage between the A leg and the B leg, the voltage between the B leg and the C leg, and the voltage between the C leg and the A leg, all three of which voltages should be the same give or take a volt or two.

Check each machine to be sure the voltage it needs is the same as the voltage provided by your system.

Not all 3 phase systems have a neutral (groiunded conductor) as a fourth conductor (where an equipment grounding conductor would be a fifth conductor).. A "wye" or "star" system has such a neutral where the voltage between any of the three phase lines and the neutral is the same.

The aforementioned 415 volt 3 phase system has 415 volts phase to phase e.g. A to B and 240 volts phase to neutral.

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