Using two legs off a Delta Three Phase 230 volt Panel

[powerplay]

It’s not like ground fault protection in a receptacle or switchgear. It is a ground detection if one phase goes to ground. It does not use CT’s.

It’s not like ground fault protection in a receptacle or switchgear. It is a ground detection if one phase goes to ground. It does not use CT’s.

I was referring to the Ground Fault Indicator Lights for the system, but with the factory plug having a “bond” pin to connect non current carrying metal together from a grounded system, looking like a transformer & ground to create a wye will be needed.

 

[powerplay]

You keep saying 3 phase 230. Is it a 3-wire or 4-wire supply? If 4-wire how do you know if it Delta or Wye? Have you tested the voltages between all phases and all phased to ground?

BTW. You need to updated your profile to included your location and profession.

I will have access to test what is available in a suite not using the power, but with only three phase 230 volt labelled on manacled do assume it has only one voltage and a delta 3 wire that I had seen in the older areas a few times.

I tried to update but wasn’t able to alter the data.

 

[powerplay]

You keep saying 3 phase 230. Is it a 3-wire or 4-wire supply? If 4-wire how do you know if it Delta or Wye? Have you tested the voltages between all phases and all phased to ground?

BTW. You need to updated your profile to included your location and profession.

I believe a 4 wire system would have a second out of phase voltage, where the 230 volt ungrounded delta is only one voltage.

 

[powerplay]

What existing single phase? I thought you said you had a utility provided ungrounded delta 240V source?

240/120V 3phase 4wire center tapped system can be provided by both closed delta and open delta transformer configurations. A lot of industry slang seems to indicate 120/240V center tapped systems are always open delta and straight 240V are closed delta, but this is not the case.

As long as you keep your single phase loading on the 120/240V lines (i.e. the A and C phases), you should not have any severe voltage imbalance assuming the utility has sized their transformer correctly.

Thank you very much for your constructive feedback !

It helps narrow options to investigate to find the solution !

 

[powerplay]

If you have ground indicating lights, you have an ungrounded system (grounded systems use other schemes for ground fault detection).
An ungrounded system will give L-G voltages readings that vary based on loading and coupling capacitance. Do not trust any L-G readings on ungrounded systems.

thank you for the constructive feedback !

I had discovered floating voltages on a delta 230 volt before and see what you mean… is there a way to detect one fsult if no indicator lights ?

 

[jim dungar]

… is there a way to detect one fsult if no indicator lights ?

There would be 0V L-G on one phase and 230V L-G on the other two.

If this is a single phase machine you can use a single phase 230V to 120/240V transformer. The 30A load should not cause an imbalance if the utility service is relatively small.

 

[jim dungar]

I tried to update but wasn’t able to alter the data.

Use the link to a Helpful Hints page where you can find a link to update your profile.

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[Little Bill]

Use the link to a Helpful Hints page where you can find a link to update your profile.

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It's been updated.

 

[powerplay]

There would be 0V L-G on one phase and 230V L-G on the other two.

If this is a single phase machine you can use a single phase 230V to 120/240V transformer. The 30A load should not cause an imbalance if the utility service is

Thank you !

I was concerned putting a delta to wye transformer grounded on secondaries might pose additional danger to ground faults on ungrounded system if transformer had issues ?

 

[Jraef]

To provide power for a Three Phase DIshwasher and Three Phase Oven, we are planning to bring a combination Subpanel into the Suite with only 120/240 volts Single Phase.

Huh? How are you going to power 3 phase machines with a single phase sub panel? Are you leaving something like a phase converter out of your description?

 

[powerplay]

There would be 0V L-G on one phase and 230V L-G on the other two.

If this is a single phase machine you can use a single phase 230V to 120/240V transformer. The 30A load should not cause an imbalance if the utility service is

Thank you !

I was concerned putting a delta to wye transformer grounded on secondaries might pose additional danger to ground faults on ungrounded if transformer had issues ?

Huh? How are you going to power 3 phase machines with a single phase sub panel? Are you leaving something like a phase converter out of your description?

I must have been half asleep posting…

The Suite has an existing single phase 120/240 volt Panel.

The goal is to provide power from a separate SE Source close by in another suite for 208-240 volt three phase 12.7 kw dishwasher, 12.5 kw three phase oven, and a single phase 240 volt 30 amp Expresso Machine from a three phase 230 volt system I presume is ungrounded, but confirming later today.

 

[Joethemechanic]

I may be reading this wrong, but if you want to supply those kitchen appliances from a 3 phase ungrounded, or corner grounded source, you are going to need an isolation transformer to create a SDS for that kitchen subpanel feeder

 

[jim dungar]

I was concerned putting a delta to wye transformer grounded on secondaries might pose additional danger to ground faults on ungrounded system if transformer had issues ?

Transformers almost never have problems, unless they are severally abused. This would not normally be something I would consider.

 

[tortuga]

In my old copy of the Canadian Electrical Code (CEC) [not to be confused with the California Electrical code]
Section 8-100 Current calculations
"When calculating currents that will result from loads, expressed in watts or volt amperes, to be supplied
by a low-voltage ac system, the voltage divisors to be used shall be 120, 208, 240, 277, 347, 416, 480, or
600 as applicable", so the correct term for the system is 240V.

The CEC section 8-102 permits up to a 5% voltage drop from the supply side of the consumer’s service (or equivalent) to the point of utilization, so equipment would likely have a 230V nameplate and be fed from a 240V service, much like our ANSI standards here.

Regarding BC Hydro’s 3-wire delta service, the delta is always corner grounded B-phase.
Any 240V load can be supplied from a 240V service, single phase 240 such as lighting or the espresso machine or three phase 240, you do always want to try to balance the load so having someone with expertise in that might be in order.

 

[powerplay]

In my old copy of the Canadian Electrical Code (CEC) [not to be confused with the California Electrical code]
Section 8-100 Current calculations
"When calculating currents that will result from loads, expressed in watts or volt amperes, to be supplied
by a low-voltage ac system, the voltage divisors to be used shall be 120, 208, 240, 277, 347, 416, 480, or
600 as applicable", so the correct term for the system is 240V.

The CEC section 8-102 permits up to a 5% voltage drop from the supply side of the consumer’s service (or equivalent) to the point of utilization, so equipment would likely have a 230V nameplate and be fed from a 240V service, much like our ANSI standards here.

Regarding BC Hydro’s 3-wire delta service, the delta is always corner grounded B-phase.
Any 240V load can be supplied from a 240V service, single phase 240 such as lighting or the espresso machine or three phase 240, you do always want to try to balance the load so having someone with expertise in that might be in order.

Interesting… you have done some designing in Canada ?

I will check today, but presume if corner grounded that I will find the “0” volt reading from Ground to “B” Phase ?

I had tried metering a different building’s three phase 240 volt (230) voltage but had readings not able to be trusted as mentioned by Jim Dunbar above as they were ungrounded for machinery to run until scheduled maintenance to repair when one ground fault was detected, as one line grounded didn’t blow a fuse or breaker until the second phase had a fault I was told.

 

[powerplay]

Interesting… you have done some designing in Canada ?

I will check today, but presume if corner grounded that I will find the “0” volt reading from Ground to “B” Phase ?

I had tried metering a different building’s three phase 240 volt (230) voltage but had readings not able to be trusted as mentioned by Jim Dunbar above as they were ungrounded for machinery to run until scheduled maintenance to repair when one ground fault was detected, as one line grounded didn’t blow a fuse or breaker until the second phase had a fault I was told.

Oops.. my apologies for the reference error.. Jim Dungar

 

[Little Bill]

Oops.. my apologies for the reference error.. Jim Dungar

That's ok, Jim Dunbar doesn't mind!