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Subject - 240 volt Delta
David Hyatt A 3 phase 225amp 240 volt panel is being installed. All that is hooked to it is 3 phase 240 volt motors. This is a Delta service, main breaker panel, will the panel only have three phase lugs and a ground bar, or does it come with a neutral bar that we just don't use???
Also the meter can does it just have three phase and a ground lug or does it lok like a regular can??????
odie Hi

I am new here. Sure would like to hear the answer to this. Thanks
JimmyDee
quote:
110.15 High-Leg Marking.
On a 4-wire, delta-connected system where the midpoint of one phase winding is grounded to supply lighting and similar loads, the conductor or busbar having the higher phase voltage to ground shall be durably and permanently marked by an outer finish that is orange in color or by other effective means. Such identification shall be placed at each point on the system where a connection is made if the grounded conductor is also present.

With this said, if the power company doesn't bring the neutral to the service and you don't bring it in, you neither want nor need a neutral bar. I'm not sure if they come without a neutral bar or not but you will not need it. If the power company runs no ground tap to the center of one of the transformers, there will be no high leg. It will be the same as any other delta system, basically no established voltage to ground. If they decide to ground the center tap of one of the transformers, you still will not need to mark the phase that is the high voltage to ground because it will not be in the presents of the neutral.
Meter can has 3 phase lugs (3 line 3 load) and will probably have a neutral lug as well and you just will not use it for a neutral.
Jim
David Hyatt You will use the neutral lug in the meter as ground. Right?
It must not be common to use a center tap neutral on a delta system around here with a high leg. The engineer didn't even give us that option. We are going with straight 240 volt for new equipment in this old building. The existing service is single phase we are just adding a new service.
I also learned today with this new service it cannot have a neutral. Something about not having 2 services in one building with two neutrals. He said only one service can contain a neutral. Is this code?? Only one service with neutral entering a building???
lctrc789 David, Unless your utility is different then the NEC guidelines all services must have a grounded conductor. Whether Delta or not.
Article 250-24 5(b) All a/c systems operating at less then 1000 volts is grounded at any point the grounded conductor(s) shall be bonded to each disconnecting means.
I have had a few of my guys install Delta services we MUST run a Neutral in the service always, if we don't we don't get power here.
Also as you probably know HIGH leg marking has to meet the utility marking or usually B phase Article 384-3 3 (e-f)
Depending on what type of meter bases they use it may be grounded or may not.
Please let me know what you find out because BY the NEC here we have to have neutral in all services Delta.
JimmyDee
quote:
250.24(D) Ungrounded System Grounding Connections. A premises wiring system that is supplied by an ac service that is ungrounded shall have, at each service, a grounding electrode conductor connected to the grounding electrode(s) required by Part III of this article. The grounding electrode conductor shall be connected to a metal enclosure of the service conductors at any accessible point from the load end of the service drop or service lateral to the service disconnecting means.

I'm not following you on this. It says that if there is a grounded conductor is shall be bonded. Where does it say you need a neutral or grounded conductor for an ungrounded system like a delta 3 phase. 480, 3 phase delta is the same delta configuration as the 240 setup and it never has a grounded conductor. You can feed the delta with 2 transformers (open delta) or 3 transformers (closed delta) and neither the 240 or 480 would require a grounded conductor for a strictly 3 phase only setup.
Jim
lctrc789 You Cannot have two seperate neutral at one point in a service to a building, it simply would not work at all.
But if you have existing service and are installing a new delta service you still have to run a neutral to the new panel where it is all equipment or not.
Or at least I will say here we have to.
JimmyDee
quote:
Originally posted by lctrc789

You Cannot have two seperate neutral at one point in a service to a building, it simply would not work at all.
But if you have existing service and are installing a new delta service you still have to run a neutral to the new panel where it is all equipment or not.
Or at least I will say here we have to.

Pat check out 250.24 (D). I would say this is the service he is going to install.
Jim
JimmyDee There is a choice with the usual open delta system 240 volt system to have it a grounded system that combines the lighting service with it and for that one you are 100% correct. Or a ungrounded system with no lighting and that one you are incorrect, at least in the rest of the country. The power company doesn't run a neutral in for a power only ungrounded system.
Jim
renosteinke There will be a note on the panel, or its' cover, detailing its' listings. This will typically state that for a delta service it is NOT to be used as an appliance panel.
The panel will come with the usual neutral bar, with provisions to bond it to the case. As with any other panel, you may have to add a separate ground bar.
IF you do need to run single phase circuits, I believe that code requires (or the listing limitations imply) that you use this panel to feed a separate sub-panel for the single phase loads.

I just had a job where the DIY guy didn'y appreciate this, and had some 208V receptacles as a result of tieing onto the "stinger" leg.